+Friedrich Ganter I am at the perfect middle between you too so I will have to decide who is on the other side. Incidentally my location (26°16'47.46"N 87°53'18.84"E) is perfectly at the center on the connecting lines of you two. Greetings from India.
35:10 I agree with you 100% when comparing this "Free" to $5.00 cheap meter to a $200 Fluke. But there are a lot of new young budding electronics engineers out there that just can't afford a $200 Fluke. 37:30 If you use the meter under 50V and a max amperage of 5 Amps this meter is accurate and safe enough for electronic/arduino type experimenting. We use these cheep meters in the shop as throw away quick checks and the Flukes as precision accurate and higher voltage use. All you seem to have done is let the younger players feel that they are idiots for using a cheap meter like that when in fact it is quite usable and accurate.
I think the same and more: the ones surprized by the precision of cheap multimeters are idiot enough to don't contrast them with their 'great' multimeter's precision and it's many times the same 0.5%. Funny when they take the expensive multimeter for precision and many times its the same lol
I don't think he was deriding that multimeter or saying it is junk, yeah he was kind of negative on it but was impressed with it's accuracy and low price. But he didn't give out a flat recommendation not to buy it just pointed out that it's a bit dodgy for non hobby work
I love the free Harbor Freight multimeters. I get one every time I have a coupon. Of course they are useless for any precision measurements, but I can hook up two or three of them to various spots on a circuit to see current draws, voltages, etc. during troubleshooting.
That Rossin item is a single-beam PIR - single beam here meaning one detection zone - and PIRs are something I know about, having designed a few in the '80s. Rossin was a US firm whose speciality was ultra-low power PIRs running off a single 3V Lithium cell and I just happen to have here the cct of their W60 I traced back in '85. The chips should be a pair of CD4001Bs and the remarked one an MC14573 quad programmable op-amp. The L & C terminal are the output, drain and source respectively of the VN01 MOSFET. The cut resistor is probably the means of switching from NO to NC output - the W60 had a link. The Iq of the one I traced was 400nA so this one may still be working. The IR sensor is a funny with only two terminals, not the normal TO-5 with a silicon window three-terminal one. Unfortunately there's nothing about it on my traced cct. If Dave asks nicely I'll scan my hand-drawn cct and notes.
+Graham Langley Found I've got the product flier. It's either the R50 (wide view) or the 70W40 (long range - 21.5m). Battery life is given as 15 years.
+Graham Langley The memory has dug up that someone had a patent on using a faceted mirror in PIRs to generate multiple detection zones - this was before HDPE Fresnel (that's 'fren-ell') lenses came along. It might be that the Rossin PVDF(?) sensor has multiple elements and so only needs a simple convex mirror.
. It's an Rossin corporation R-50 THERMAL INTRUDER SENSOR Still available as surplus stock : www.radwell.co.uk/Buy/ROSSIN%20CORPORATION/R50?redirect=true .
I had an SC110 scope from new - at the time it was about the cheapest new scope you could buy. One of the transformer overwinds is for the filament - done like that for either HV isolation or low capacitance. Thandar was Sinclair's test equipment division - changed the name & split off when Sinclair went into computers. They later merged with Thurlby to form TTi. I met someone recently who worked there at the time - some of the old guys are stil there at TTi
+mikeselectricstuff One of the electronics mags around at the time did an article on the circuit design of this. Can't remember which one and my copy may have been recycled some time back. Edit: Just remembered a couple of things. The case was borrowed from something else and wasn't quite big enough internally to accommodate the flare of the tube, so the walls had to be milled out to make room. And the rechargeable cells they sold for it were AAs in a C-sized sleeve, which you only found out after you'd bought them.
Wonder if the rossin thing is a beam-break detector - that would explain the lack of facets (though may be a faceted lens insid the copper can) . Battery may be to provide pulse power due to 2-wire connection, or maybe biasing the sensor
+mikeselectricstuff Thermal Intruder Sensor? www.ebay.com/itm/Rossin-Corp-Thermal-Intruder-Sensor-6678-/131405385387 (don't mind me, commenting before finishing the video...)
Honestly though. Those cheapy multimeters are pretty reasonable for everyday use. I think in this day and age it's pretty easy to make a reasonable multimeter that would work perfectly fine for hobby level projects for pennies. That said if I had to mess with any actually high power stuff, that would not be my first tool of choice.
My father was given that Harbor Freight DMM (in yellow) as a door prize, just for walking in during a promotion. He complained that it had malfunctioned, and that sparks shot out...upon further investigation I can't really fault the meter as my dad tried to "test how many amps the kitchen circuit was" by putting it in the amps range and sticking the probes in a wall outlet!!! LoL I told him I'm glad he's still living. The failure mode was 3-fold: The fuse charred (probably still passing mains), traces on the board started to lift and blacken, and the black probe lead failed open. Miraculously, with a new fuse and leads the meter seemed to work just fine! I warned him to keep it away from outlets, and removed the traces to the amps range to help protect my pops from himself in the future.
+Stephen Tack Well, I did it with Fluke 333 on ohms range. Twice! The result: 2x burned 16A fuse (ceramic 220V/16A) + set of burned leads. The 333 is unharmed and happy. Me to.
Love this post Dave, reminds me of when my boys were young. Hope I meet you one day in Castle Hill Towers as we go there often. Would love to shake your hand...lol. My father was an Electronics Technician and was almost as good as you are introducing me to the physical universe as you are to Sagan. Thank you for your authenticity. Live long and prosper my friend...and if time seems to be passing too fast, remember 88 miles an hour can bring you back.......
Speaking of Sagan I've not seen him in a more recent video in a while it may just be that I haven't happened run across one a little bit but just thought I'd mention it have not seen too many Eevee Blog videos recently so might be part of the reason for this. Also anyone know how old saying it is at this time? And yes I remember project Seguin of course and also the other kiddo of his as well course I thought that was hilarious when he did that that was the way to go I believe especially since the type of work he does what a way to introduce the new family member to the world. Also I once knew some way that work for a company that designed toys years ago and they did something similar when they had a new kiddo in the family it was basically a fake doll type of reveal I thought of that when I saw project Seguin although the doll thing was years and years ago but I still remember seeing it on the Super 8 film when they did the reveal to the family yeah it was that long pre VHS
+Macpod HOW IS THAT A FEATURE? (caps lock, to lazy to re-type) like.... how could that be useful besides confusing your friends? here use this meter, its 100% accurate. if i let off the gas quickly in my truck it pops out of 3rd gear... thats a feature, it shifts for me!
It's a battery gauge, you connect it to precision voltage reference and depending on voltage shown by meter you know how much energy is left in the battery.
+RadRider33 yup, still have one myself, good 10 year old design. But it works! and it's better to have a multimeter than not have one (and I don't really do in electronics to have requirement of better than like 5% precision)
+RadRider33 I have a Harbor Freight about a 1/2 mile down the road .... Whenever they go on sale for $2.99 I pick a couple up. Got one in my boat, my truck, my car, next to my main desktop, the garage workbench and a couple sitting on a shelf unopened. I don't even bother changing the battery because the cheap leads will be on their last leg and break before the 2nd battery goes dead. I just pitch it and grab another off the shelf The leads used to be a lot better, larger gauge and better insulation , no way would I trust the new ones to take 10 amps, the resistance of the leads would be 10 times or more than the shunt and the measurement worthless anyway Good enough for 12V boat and auto circuits, testing batteries and continuity checking although I think they should just ditch the transistor tester and add a continuity buzzer on it's place
+RadRider33 that design was my first multimeter too. got it like for 6 dollar local currency equivalent like 10 years ago. Mine died sadly (numbers jumping for no reason, no measurements on any range), lead broke somewhere inside. Still have it as my first dead measurement instrument.
Sagan is fantastic. Great to see him getting into that MakerBeam kit. Way to go, and greetings from Seattle, Washington (specifically Kent, Washington)!
When Segan is in his teenage years or so, he'll be able to look up old footage of his early childhood on TH-cam... Kinda weird if you think about it, the first really "digital" generation post 2010's
+Osmosis I'm 25 and I even I still find this a bit scary. The oldest footage I have of my childhood is all recorded on cassette tapes and faded images.
+Osmosis i dont know if weird or disturbing how easily everyone will be able to look up all your embarrasing moments digitally at typing speed, in our age you'd have to dig up some old VHS-C tapes(if someone was even filming in the first place) -pray they're labeled properly- and essentially watch the entire thing to find out something or clumsy FFWD, maybe a photo album. Now with a camera/video in everyones pocket ready to record in seconds, failarmy and yt every blunder with haunt you forever :D
Have one of those multimeters for 10 years now and works perfectly. Nowadays I have a Fluke 179 and I like it but to be honest for my needs the cheap China multimeter would do the job perfectly. Highly recommended
the Rossin device that you showed on # 813 is a passive infrared sensor for a burglar alarm. It is intended to be wired in a normally open alarm loop. the battery actually powers the device and i think it should last for ten years . I used some of these probably 30 years ago. will look to see if I have any info on it. Love the Blog. Thanks for what you do.
I have one of those just for continuity and reading voltages on where i don't have any idea of how much tension it is (and don't give a fck if i burn it haha)
@@TheCode-X The gadget is not what you should be concerned about. The worry is about the effects on your person of its explosive disintegration by massive overcurrent.
Speaking of a bulb with two wires I used to have that same setup for testing voltage when I first started out you're doing electrical projects it was one that was handed down to me from another family member. It was homemade but still in good shape even with the original test leads that probably had been re-soldered a few times originally one was red and one was black but one had to be replaced. From what I was told and I also had a second one that is made by the same person that had longer leads but had two bulb sockets so that it could be used anywhere from 120 volts up to 220 Ameri fact I remember hearing about in some way somehow possibly from different sources how's that the utility company when connecting up to a residence when running new wiring for overhead lines Wood Lamp out to connections at the service entrance from their wiring to the service entrance whenever first connecting using a setup very similar to that also I still have a continuity tester flashlight that was given to me years ago is still works although I did converted to an LED it still is a nice flashlight also somewhere I still have a few of the old from colored not necessarily chromed but I think one or two are metal C or D cell flashlight I think a couple r c and a couple Rd also have a few lanterns stowed away somewhere that would have used the racial big 6 and 4 volt batteries I'm thinking about converting them some way to recharge mobile maybe you're sealed lead acid and perhaps a built-in power bank? Although I do have one Lantern or two that had a quarter inch track originally on there one even had two of them perhaps one was added? So that you could use it with a headlamp in addition to your Lantern and yes the original coil cord is still in good shape believe it or not. And there was also an area like that could plug into the second Jack. There was a switch for both receptacles and also a switch on the lights themselves as well. Can't remember if that was a 6 or 12 volt Lantern but I think that one was 12 it's stashed away somewhere but not where I am right now. Also have a land foreign pride of similar except it's got a cord and 2 rounded is 1 would Connect into the front of the lantern in place of the Winds and reflector assembly and the other is essentially the head of the lantern that the bulb in reflector assembly goes into to turn it into a hand Lantern from a battery pack type Lantern again it was one that took the large alkaline or whatever it would have either been 6 or 12 volt battery you know when the big Lantern batteries they don't see much anymore. Also I do have some sealed beam 4.5 volt Lantern bulbs don't even know why I have them are where I got them possibly an old hardware store did they still sold those lights and may have closed down but don't know we're no longer sold the lights who knows just one of those random things I got over there years at places that could get stuff from cheaply where is somebody could have been used for something else and sometimes when something like that would come up I could arrange to get all of them Ford even further reduced price especially if I knew the business on her well in which law of cases I did that I was known for picking up stuff that there's only a few things left an inventory they're getting rid of Good Times those times I'd say.
@@stephenarling1667 yes I would agree I have one of those testers which is actually a modified Automotive work light modified in terms of a jack with test leads and another Jack with alligator clips for battery and our Jack with the cigarette lighter connector I Know Jack with female banana plugs And also a set of very long coiled test leads with male female banana connectors. Is that should be in everyone's test kit does extension lights same with alligator clip to Banana plug leads and just about any other type you could think of or come up with even if you make it for one specific test put it in your test kit for lighter you will thank yourself for this. Also speaking of a bulb and Automotive there's times that I did not have the proper materials or tools to do testing and what I would do would just pick up a pack of pull volt indicator lamps the ones that would be worrying that had the blue green or whatever colored plastic around them that was meant to snap into a hole in a panel and just attaching wires it works plus you had indicators for another project in the end one time I even round up using a switch with a 12-volt bulb in it because I could not get an indicator but I could guess which or it was just a viable I don't remember long time ago but I was in pain and it worked I was able to get whatever it was working it need to be to under right then and there. Also if I was working on something for somebody and did not have a proper meter or continuity tester available I would go somewhere and get a battery holder and an indicator of some sort with nibia 4 volt bulb and maybe a 4 C or D cell or double A or AAA holder and make a Jerry Reed continuity tester out of it and then of course save for parts for another project later I fixed a hair dryer doing that once all that was wrong was there was a broken piece of wire between two points in the device this was actually not the handheld dryer but a Hood Type dryer a very expensive one and the person used it all the time and wondered if I could try to fix it for them Ameri fact the wire need to be high temperature and that was salvaged from something else that I could not fix during about the same time can't remember what was it may have been either a heater or a toaster or perhaps a little mini countertop stove I had prepared several things for them previously was in about a month's time so can't remember but this was many many years ago probably in excess of 20 years but yet the mind is still sharp pretty much Seems Like Only Yesterday that I got my first electrical tester of any type. By the way was going through some stuff and found my first actual continuity tester that I had gotten from somewhere yeah sure the batteries were left in it corroded do you know where however once I get cleaned up it's going to live on although I already found a way to replace this the original spring which was corroded into two pieces which was the new spring was actually a salvage spring or something and two metal pieces I think that were a battery contacts for something recently folded over on either end of the spring and also they fit exactly without even stretching the spring or anyting so just pretty cool what you can do or salvage parts and also things that you jerry-rig even for one temporary use just to fix one thing.
I used to watch my dad work on electronic projects at his bench. When he went to the electronics store on a saturday it was like christmas! I dont do much with electronics like he did but still enjoy putzing around with things of that nature. I find myself doing more electronics than ever now that I am back into RC Planes and lighting my plastic models as well as my planes and helicopter.
It's so interesting having Sagan helping you, nothing like a child to help out, they always have interesting comments.. He's quite the geek already, just like dad...
Hi Dave, Love it. My dad 'lent' me one of the Thandar scopes in the early 80's It was branded RS Components (UK) and as I recall it cost just over 100 UK Pounds at the time. It was part of a series that included a matching frequency counter and multimeter. It finally packed up about 10 years ago, and I'm ashamed to admit that I still use the probe that came with it! I used it to trace trigger card faults on thyristor lighting dimmers and the fact it was 'ground' free was really useful. It started displaying the same issues you discovered about 10 years ago and finally died soon after.
Have been trying for years to get those modular beams from Bosch Rexroth, can't find them anywehere and Bosch doesn't even answer to consumer emails. But Sagan is the first kid I have seen putting things back were they where (winding the wire back to the spool) instead of taking everything out! Good job Dave!!!
Seeing Sagan made me nostalgic - I used to teach pre-school, which in the US is for 4-5 year-old children (kindergarten is reserved for 6 year-old). I love their curiosity about the world, which Sagan shows frequently - 'what are these?' 'what is this for?' etc. Fun teaching that age, before they've become too cool to ask questions and become bored with school.
I've got that multimeter, which is why I was particularly interested in this video. I thought you were going to say it's a death trap. I'll keep it away from the mains per your advice though. I've got another multimeter I can use for that, and I know that one's safer because I actually had to purchase a SEVEN dollar torch to get it.
I've been using that Cen Tech multimeter for several years now, still works like a charm! Mine was free with a dollar purchase of tape. The leads broke at a point, but I fixed them with some solder and hot glue. No problems with the meter itself!
I remember in High school electronics class we a like 7 or 8 of those 7 position Harbor Freight multimeters and two or three Triplett 630-PL meters and almost everyone else preferred to use the Harbor Freight meters but whenever I could I used the the Triplett. I loved those meters.
I can already imagine the teacher calls Dave and telling him "I sent him to play with the other children and after five minutes I saw him taking apart everything and all the kids shouting 'Don't turn it on! Take it apart!' "
Re: Cen-Tech multimeter. I bought one of these 6-7 years ago. $3. It has rattled around in the tool box all that time, and always works. Original battery. The transistor tester is useless, but the battery tester is not, I use it and many other features most every day. Recently, the probe wires wore out, and I elected to buy new wires rather than a new meter. For the average person, it is fine. Every value I have been able to cross check is reasonably close.
As someone who barely knows what he's doing it's good to let me know if my better Radio Shack meter is working or if I'm doing something wrong. I bought it for the transistor tester which is not great and because at $3 how can you not.
10mhz for that scope is damn good, i got myself a "old" analog scope here with only 1mhz bandwidth. probably with tubes inside havent it taken apart yet.
I have gone through at least 5 of those Cen-Tech multimeters. I have never had to change the battery. They blow up before I get to it. Wear the right gloves and it can be safe enough. The case holds in most of the pieces of the pcb and battery
Thurlby Thandar was a company that joined with Sinclair Research and indeed some of Clives calculators ended up in Thandar cases. They were both in Cambridge of course and there was a fascinating array of product made by that pairing.
The breathalyser is probably a generic flammable gas detector. It consists of 2 wires, one coated with a catalyst, and one not. They are wired with 2 resistors in whetstone bridge configuration. The wires are heated by a small current, but normally remain balanced. If there is alcohol on the breath, the catalyst oxidises it, and adds heat to the catalytic wire which increases in resistance unbalancing the bridge. All you need to do is measure the bridge imbalance and if it is over threshold turn on the light.
So far, I own 4 of those free Harbor Freight Tools multimeters. At first I figured they would be very inaccurate, but was surprised at the accuracy. I also figured they would be unreliable, but so far they're reliable enough for use in non-critical measurements. I keep one in each vehicle, monitoring the battery voltage, and after several years, they still do a good job. They even give good readings at 30 degrees F below freezing and 120 degrees F. I've had them read incorrectly about 2 times. I quick rotation of the switch, and they're reliable again. I only use them when I already know what reading to expect, so I can tell if they are off very far. Not to be fully trusted, but still useful.
It's PIR, I used very similar units made by Racal back in the early 80's. It had an operating life of about 5 years, and used the on board battery. After the unit detected motion, it would "sleep" for a period of time, to save battery life. That unit was clearly a single narrow beam type sensor.
The Rossin thing looks exactly like the one my friend had in his house back in the 80s, I think it had a send and receive on either side of the hall way, I remember having to slide under it when we would skip school and go to his room to play video games on the Atari lol
I've bought a nice Amprobe AM550 when I started in EE. Now some time later I needed some more multimeters and I'm on a really tight budget, so I've ordered two of those from ebay. They will do it and for the more precise jobs I'll just use the Amprobe one.
I've been wondering if you would be interested in doing some small side projects for the channel on a regular or semi-regular basis? For example, I think it would be fascinating to see you try to work up your own version of that Thandar portable oscilloscope. Perhaps these little projects could even be given away from time to time. :)
Dave used to develop and sell kits. Like the uWatch. But he wrote some time ago, that is a lot of afford and trouble. Even shipping bis uRulers was a mess and that was a plain PCB. I would love to see him continuing the uSupply, but I also understand we he is not.
IIRC the switch on the alco tester is just for the light. To measure your alcohol level, hold the push button depressed until the green led lights up, then blow gently onto the sensor.
Actually I think Sagan would be better with a fluke meter once he's old enough to be responsible using it of course I would not trust that meter with if I had a son for his own protection and would have him a decent meter for full protection for inputs than all that because people make mistakes when they measure things that's why that production is supposed to be there if he were to blow up a meter she would learn Omar send it about proper testing protocol for example blowing the HRC fuse would let him know that poops I did something I should no not to do instead of having the meter blow up in his hands and possibly mean never able to test any circuit again due to a messed up hand or worse possibly be no longer among the living because of a cheap alternator scratch that multimeter Google you know The Giver of pain and sometimes laughter and other times just frustration LOL.
They don't practically away, they do just give them away. With a mail/online coupon you just walk in no purchase necessary and show them the coupon and they give it to you free.
Those cheap multimeters are perfect for checking battery voltages, or continuity (if your model has that feature). I have dozens of these laying around. I do have a couple good meters but they don't get used unless I need precision. I used one of these recently to diagnose an electrical fault in my car, worked perfect.
Cen-Tech meters are good for solving quick and easy problems, and cheap enough to have everywhere. But I did notice one major problem. As they get older, they start to loose accuracy, especially the ohm meter. Not sure if it's battery related, but the meter is cheaper than a proper 9v battery.
I have the 92020 version of the HF which includes a gorgeous orange backlight and is surprisingly accurate. I would never put 10A through these. So what i did was use all that empty space inside to convert it to a 4-wire tester by putting a good rechargeable lithium ion battery from an old cell phone + powerbank chip + a homemade LM317 100 mA constant current circuit inside, with a 2P connector in place of the 10A jack. Everything else still works off 9V, but I get the most use out of checking USB cables with the 4-wire-on-demand feature I added in conjunction with the 200 mV setting (multiply by 10 for milliohms). I don't know if anyone makes a small portable 4-wire tester like what I now have? I know this multimeter is a joke, but not everybody needs a big knife! A really nice meter for someone who can't afford much.
I think I may have been like that as a kid judging by what I already knew by the age of five or even 4 for that matter some people say because at that time I was rewiring hundred twenty volt AC lamps yeah I was repairing lamps at 5 years old so yeah I think I got sick and Beat just Maybe Kinda sorta.
Got one of those multimeters for free from Harbor freight a few years ago, wish I had read the instructions the "do not operate tool under the influence of alcohol or drugs" part is great.
33:45 to 43:30 ... Well done on missing the whole point of those cheap multimeters. Being cheap enough to be classed as disposable it's handy to have a fairly flexible and relatively accurate device of this type in your car, bike, boat, etc where it doesn't matter much if it gets damaged. It's better than risking an expensive one in such potentially unfriendly environments.
I have maybe ten of these Harbor Freight multimeters, and I LOVE them. I use them for doing assembly work primarily, and may need to ensure that 12 volts or 24 volts, or whatever is actually present. But may go ten or 20 minutes between uses. These are the only multimeters I own which actually have an on-off switch So they get used quite a lot. I have better multimeters which I grab when I need to actually need to measure something.
found this patent about an intrusion detection device from 1974 by J Rossin www.google.com.br/patents/US3839640 note this part: "This invention using a 1% inch diameter concave mirror can easily detect a moving person 25 feet away. Larger mirrors will, of course, detect from greater distances." Dave I'd suspect that multimeter brand would send you their most accurate product from the test line just to make a scene.
By the way nice find on the patent on Google will read full thing eventually saved it to favorites. Just a quick skim over it pretty intriguing and interesting that's something quite a bit different than most motion detectors for sure and also the device that you're referring to in his video yes very different but the problem would be must have battery dies would it be able to indicate nurse an issue with the sensor? Maybe if do barristers to get low input sound of a certain parent of false detections the indicators a problem with the sensor or something of course a system designed like that would probably have a way of determining if the sensor had an issue or the battery was getting low but it may have been too early for that but if you're a lot of them I can see if there was no way to indicate if there was a brown with battery or sensor if you have a lot of those it could get confusing or say it was in an awkward to get at place just trying to figure out what was going on I could see that if it had had it replacement batteries in a battery holder both Glow Draw lithium would be better but still something like that being solar powered by a lithium battery in hard-wired into place but an advantage would be you would not need power after detector simplified wiring and hook up for the sensor but it's kind of Niche product I'd say just an odd one in general I doubt they still use things like this or somewhere like that would still be available is with all the advances and more modern systems? But may still be in service somewhere someone out doing something who knows. Also I I have seen very old motion detectors that were humongous in Old buildings and even Tone Ultra Sonic alarms are basically obsolete even the box that could be set on a shelf self-contained ultrasonic alarm probably from the 50s or 60s still working to this day. Have Salvage all types of equipment like that for parts and repurposing old alarm systems that were functionally obsolete for who knows how many decades you know the old green box up on the wall it'd be rectangular and probably have a battery in it likely number 9 drawer cell in some cases. So those were essentially a glorified exit alarm for a door some of them even had the hardware for that accept had a small relay module how do I know this I've seen the door alarm version from the same company and the alarm version from the same company most of the inside is identical. Sometimes I do work to liberate things for Salvage in others as part of the deal for something that need to be done and sometimes I got more than I bargained for like once almost a whole basement full of old equipment. Also I did actually couple times use old remote control systems that work for TVs that were ultrasonic and repurpose them for other projects. Although one of the more interesting remotes I've seen was not ultrasonic or infrared basically a glorified flashlight with a relay that would flash the bulb an each Button had a specific flash pattern and it was repeated I think twice maybe three times to avoid false triggering ingenious but it works and yes there was a push button to use the remote as a flashlight which I thought was just why not. The remote was a bit bigger than an older garage door remote I think it took 2 C batteries side by side at the bottom of it many years ago. Also I once saw a toy CD player music box crayon saying it similar to the one that Radio Shack made except it had a remote that basically work the same way which I found out that particular one deliver or not I was able to take the output of that separate circuit board and make it do my bidding can't remember how but I was able to decode it interesting it was two easy dinner face it may have been serial or parallel it seems like Pearl alderman except a few signals put out more than one pint of ones but it seems like the rest of the others would always only be active with one button there was also a word that was active for invalid signals inhibit? Although I built a CD jukebox system once I got a hold of this equipment that originally used what look like off-the-shelf mini mini disc CD changers except some different controls on a front additional things this weld are on the back more Jack's Imports than you can shake a stick at evidently if you could think of a way to control it it could do it out of the boss parallel port serial port an even individual + 5 to 12 volt triggers for each function seriously definitely some sort of product that was meant to be incorporated into something else I got a lot of these at one time don't remember why I want to fool with them but I did reuse them of course not going to take that part and scrap it when you could build your own jukebox essentially but you got it could be used Standalone and there was a separate remote for Standalone it did not operate any of the other functions or any of that as well not only that they could even be powered by other than line voltage AKA DC and the power supply even Han outputs for other voltages for external are an external connector so basically a prank it was designed to be around designed to be used with whatever application you wanted it to be used for that you might want to control CD playback but yeah mostly look like an summer gear which was strange you think that something like that would be in a rack-mount case but it wasn't but evidently that will available as well strange again. Also all the audio and everything was run out to multi pin connectors in addition to Indian kid actors and others and with the multiplan connectors they also went through audio switching as well which could be controlled by remote and or other inputs so evidently it could Multiplex or switch audio from one or more of those players to a common output so just one of the weirdest things I've seen along that line of those kind of things but just interesting nonetheless and useful even after the original application was done for I had also a lot of these are spare units as well so don't know where they were so came from where the story but car from someone else there was a hole in my trunks and fousey August he kept a few but the rest not so much also got several years to other people as well that could use them
Also as for the last part of your comment I bet you if it hasn't happened yet it will of course it usually does? Also remember to chinese-made phone charger I think it was where there was a ridiculous thing about they're hand-tuned or whatever spark gap and all that crap and no words a defective product that had been written up like that was intentional and also and it was chinese-made if I'm not mistaken and it did go by the name that's commonly referred to as Chinese junk from a certain Market can't think of the name of it at this time but it was hilarious and evidently that was actually from the factory and they sent it as a gag but still rather entertaining kind of reverse of what you'd expect but I think they wanted to have a laugh really who knows how long it took them to find one exactly like that so they could do that.
I Do not toss out cheap DMMs, Use as a DIY>panel meter< or DIY test box, has on /off switch so U can tap your power. -as them 1$ multi-meters make for good DIY custom solo-meter test box, just fix the range for the job u need check the calibration< & add buffer /shunt ..esc. - Also - when I was 8yro I did test the wall outlet with my dad,s analogue meter as most radios at that time , had HT of 400V
It's basically the standard Mastech DT830B except all the Cen-Tech ones have the battery tester with a switch where as the other DT830 devices usually have the knob control the power and no switch. Some of the Cen-Tech multimeters even have Mastech molded into the plastic of the lead ends. If you're planning on giving it to Sagan, make sure you didn't loose the two ball bearings that are in the knob. I saw them fall out when you were rolling it around.
I got a few of those HFT mulitimeters (for free). I was thinking of taking the thing apart so I could embed the multimeter as a voltmeter in a home brew power supply. I'd have to some how wire the lcd to the board with ribbon cables and short the right lands on the range switch for the desired voltmeter range. I might even be possible to cut the main board down a bit since I might not need all of the circuitry on it, I'd have to trace the layout out and figure it out. The thing just might make a serviceable DC voltmeter for a project.
Hey Dave, did you not show us those beautiful postcards from my fellow colleague Tony / Toni from Deutschland, did you? :) Loved the mailbag video with Sagan talking!!!
I've had a Cen-Tech meter for several years and surprisingly it still works, mine looks almost identical to the one here except it has a backlight button in the upper left area by the DCV label.
Hooray for the little multimeter.. Fantastic value..fit for purpose ..budget product.. Fills its marketing niche well.. Does not deserve ridicule or scorn.. Dave ... point out the limitations ... evaluate manufacturing considerations.. but showing so much disdain for an engineering, manufacturing and marketing success only lessens your professional credibility........ I think it is nice for Sagan to come along for the ride ,but daddy is driving and needs to focus on the job at hand..
You can be an aerodynamicist, a theoretical or particle physicist, an actor, director, a painter or a musician. But, in the end, if you are not a good, dedicated parent, you are not much as a human being. My respect for you just grew massively. Im 100% sure little Sagan will grow up to be an outstanding human being :) I wish him all the best :)
I have such a cheap multimeter for years now, it had to withstand many troubles with me. Shorts ( even with line voltage ), overcurrent in current measurement and so on. The contacts for the probes are worn now and the measurement is incorrect as hell. Well, time to spend another 5 bucks, there good for my needs :)
As others have said the unknown sensor is a PIR type device. The lack of fresnel will just mean the detection area will be very narrow, could be a people counter device.
I have one of those, this is the multimeter use on construction sites, where it is very likely to get damaged or stolen. If it got stolen or kicked off a building, don't even need to bother about finding it, and its so cheap nobody would bother stealing it, and if they did I wouldn't even care.
Wow, they actually got a trimming pot inside of this one. On couple of these ICL7106 ripoff meters that I've bought in the local shopping mall because they costed less than the 9V battery inside they actually cut costs by replacing trimmer with just a regular resistor... And a bit of plastic cost by omitting the battery chamber and just randomly sticking the battery between PCB and case.
That "free" multimeter looks like one I borrowed from a friend to help me fix his friend's TV set. Fortunately it was adequate, and it was just a failed fuse with no obvious cause. I had the set working again in under an hour, including going to a shop for the part. Transistor sockets are definite frippery.
Dave, Germany isn't on the other side of the planet. Australia is.
Greetings from Germany.
Ahahahah you made my day
haha, greeting from Australia..
+Friedrich Ganter I am at the perfect middle between you too so I will have to decide who is on the other side. Incidentally my location (26°16'47.46"N 87°53'18.84"E) is perfectly at the center on the connecting lines of you two. Greetings from India.
+Friedrich Ganter The antipode of Sydney is a 1500km or so west of the Straights of Gibraltar.
Thankfully for Australia
35:10 I agree with you 100% when comparing this "Free" to $5.00 cheap meter to a $200 Fluke.
But there are a lot of new young budding electronics engineers out there that just can't afford a $200 Fluke.
37:30 If you use the meter under 50V and a max amperage of 5 Amps this meter is accurate and safe enough for electronic/arduino type experimenting. We use these cheep meters in the shop as throw away quick checks and the Flukes as precision accurate and higher voltage use.
All you seem to have done is let the younger players feel that they are idiots for using a cheap meter like that when in fact it is quite usable and accurate.
Exactly
I think the same and more: the ones surprized by the precision of cheap multimeters are idiot enough to don't contrast them with their 'great' multimeter's precision and it's many times the same 0.5%. Funny when they take the expensive multimeter for precision and many times its the same lol
yeah but it's good enough to check a double a battery
I don't think he was deriding that multimeter or saying it is junk, yeah he was kind of negative on it but was impressed with it's accuracy and low price. But he didn't give out a flat recommendation not to buy it just pointed out that it's a bit dodgy for non hobby work
Here In india, I have seen in all the repairing shops in my hometown they use this multimeter for working with both dc and ac voltages(230 Volts)😥😥
I love the free Harbor Freight multimeters. I get one every time I have a coupon. Of course they are useless for any precision measurements, but I can hook up two or three of them to various spots on a circuit to see current draws, voltages, etc. during troubleshooting.
That Rossin item is a single-beam PIR - single beam here meaning one detection zone - and PIRs are something I know about, having designed a few in the '80s.
Rossin was a US firm whose speciality was ultra-low power PIRs running off a single 3V Lithium cell and I just happen to have here the cct of their W60 I traced back in '85.
The chips should be a pair of CD4001Bs and the remarked one an MC14573 quad programmable op-amp. The L & C terminal are the output, drain and source respectively of the VN01 MOSFET. The cut resistor is probably the means of switching from NO to NC output - the W60 had a link. The Iq of the one I traced was 400nA so this one may still be working.
The IR sensor is a funny with only two terminals, not the normal TO-5 with a silicon window three-terminal one. Unfortunately there's nothing about it on my traced cct.
If Dave asks nicely I'll scan my hand-drawn cct and notes.
+Graham Langley Found I've got the product flier. It's either the R50 (wide view) or the 70W40 (long range - 21.5m). Battery life is given as 15 years.
+Graham Langley The memory has dug up that someone had a patent on using a faceted mirror in PIRs to generate multiple detection zones - this was before HDPE Fresnel (that's 'fren-ell') lenses came along.
It might be that the Rossin PVDF(?) sensor has multiple elements and so only needs a simple convex mirror.
.
It's an Rossin corporation R-50 THERMAL INTRUDER SENSOR
Still available as surplus stock :
www.radwell.co.uk/Buy/ROSSIN%20CORPORATION/R50?redirect=true
.
sign of good parenting, your kid moved their hands away from the knife
I noticed that too. Top work Dave!
I had an SC110 scope from new - at the time it was about the cheapest new scope you could buy. One of the transformer overwinds is for the filament - done like that for either HV isolation or low capacitance.
Thandar was Sinclair's test equipment division - changed the name & split off when Sinclair went into computers. They later merged with Thurlby to form TTi. I met someone recently who worked there at the time - some of the old guys are stil there at TTi
+mikeselectricstuff Thanks for the info Mike.
+mikeselectricstuff One of the electronics mags around at the time did an article on the circuit design of this. Can't remember which one and my copy may have been recycled some time back.
Edit: Just remembered a couple of things. The case was borrowed from something else and wasn't quite big enough internally to accommodate the flare of the tube, so the walls had to be milled out to make room. And the rechargeable cells they sold for it were AAs in a C-sized sleeve, which you only found out after you'd bought them.
Wonder if the rossin thing is a beam-break detector - that would explain the lack of facets (though may be a faceted lens insid the copper can) . Battery may be to provide pulse power due to 2-wire connection, or maybe biasing the sensor
+mikeselectricstuff Thermal Intruder Sensor? www.ebay.com/itm/Rossin-Corp-Thermal-Intruder-Sensor-6678-/131405385387
(don't mind me, commenting before finishing the video...)
+mikeselectricstuff Nope, it's a PIR.
+mikeselectricstuff i think is that or signal jammer
It looks like this: www.google.com.br/patents/US4468658
Honestly though. Those cheapy multimeters are pretty reasonable for everyday use. I think in this day and age it's pretty easy to make a reasonable multimeter that would work perfectly fine for hobby level projects for pennies.
That said if I had to mess with any actually high power stuff, that would not be my first tool of choice.
My father was given that Harbor Freight DMM (in yellow) as a door prize, just for walking in during a promotion. He complained that it had malfunctioned, and that sparks shot out...upon further investigation I can't really fault the meter as my dad tried to "test how many amps the kitchen circuit was" by putting it in the amps range and sticking the probes in a wall outlet!!! LoL I told him I'm glad he's still living.
The failure mode was 3-fold: The fuse charred (probably still passing mains), traces on the board started to lift and blacken, and the black probe lead failed open.
Miraculously, with a new fuse and leads the meter seemed to work just fine!
I warned him to keep it away from outlets, and removed the traces to the amps range to help protect my pops from himself in the future.
+Stephen Tack
Well, I did it with Fluke 333 on ohms range. Twice! The result: 2x burned 16A fuse (ceramic 220V/16A) + set of burned leads. The 333 is unharmed and happy. Me to.
zlotvorx fool me once...?
Love this post Dave, reminds me of when my boys were young. Hope I meet you one day in Castle Hill Towers as we go there often. Would love to shake your hand...lol.
My father was an Electronics Technician and was almost as good as you are introducing me to the physical universe as you are to Sagan.
Thank you for your authenticity.
Live long and prosper my friend...and if time seems to be passing too fast, remember 88 miles an hour can bring you back.......
The wife and I love the videos with Sagan. He's an awesome kid and smart like his daddy!
PS. Sagan is going to be a bit of an Einstein compared with his peers at big school.
Definitely! the way he speaks rivals many adults lmao
+mart fart He's going to go to school and tell all his friends about his 10Mhz reference oscillator!
Dave, I wouldn't bother with a pension plan. Sagan's going to be wealthy chap - who'll be able keep you in style during your old age ! ;-)
Speaking of Sagan I've not seen him in a more recent video in a while it may just be that I haven't happened run across one a little bit but just thought I'd mention it have not seen too many Eevee Blog videos recently so might be part of the reason for this. Also anyone know how old saying it is at this time? And yes I remember project Seguin of course and also the other kiddo of his as well course I thought that was hilarious when he did that that was the way to go I believe especially since the type of work he does what a way to introduce the new family member to the world. Also I once knew some way that work for a company that designed toys years ago and they did something similar when they had a new kiddo in the family it was basically a fake doll type of reveal I thought of that when I saw project Seguin although the doll thing was years and years ago but I still remember seeing it on the Super 8 film when they did the reveal to the family yeah it was that long pre VHS
Sagan's Australian accent is adorable! great video as usual Dave!
+iTsTheVoLtAgE Sounds a bit English to me. Is his Mum an Aussie or a Pom? (Cute either way.)
These cen-tech meters will report different readings based on the battery voltage. Some may consider this a fault, but I think it is a feature.
+Macpod HOW IS THAT A FEATURE? (caps lock, to lazy to re-type)
like.... how could that be useful besides confusing your friends? here use this meter, its 100% accurate.
if i let off the gas quickly in my truck it pops out of 3rd gear... thats a feature, it shifts for me!
+kain hall It's a subtle feature to let you know this meter is garbage, mate :)
It's a battery gauge, you connect it to precision voltage reference and depending on voltage shown by meter you know how much energy is left in the battery.
I have one of these. The useful thing is, even when the battery is completely dead it still measures 5.5 ounces.
When the battery dies, just go pick up another free one. :-)
I love Sagan's english accent...?..go figure Dave
+MacVision Could be Pepper Pig and Mr Maker!
+EEVblog Peppa Pig seems to be really popular nowadays.
+MacVision sounds exactly like all of my nephews, must be pepper pig
+MacVision Exactly what i was wondering about. As a non native english speaker i thought i maybe mistaken it, but obviously i´m not :D
+MacVision that will disappear when he starts school
Grew up using these cheapie meters. I've still got one lying around, except mine has *gasp* a backlight!
I've got that meter too. I'm still using cheap tools and salvaged parts. That was my first meter, and its actually my favorite.
+Alex Kantor And I paid like $10 for that meter!
+RadRider33 yup, still have one myself, good 10 year old design. But it works! and it's better to have a multimeter than not have one (and I don't really do in electronics to have requirement of better than like 5% precision)
+RadRider33
I have a Harbor Freight about a 1/2 mile down the road .... Whenever they go on sale for $2.99 I pick a couple up. Got one in my boat, my truck, my car, next to my main desktop, the garage workbench and a couple sitting on a shelf unopened. I don't even bother changing the battery because the cheap leads will be on their last leg and break before the 2nd battery goes dead. I just pitch it and grab another off the shelf The leads used to be a lot better, larger gauge and better insulation , no way would I trust the new ones to take 10 amps, the resistance of the leads would be 10 times or more than the shunt and the measurement worthless anyway
Good enough for 12V boat and auto circuits, testing batteries and continuity checking although I think they should just ditch the transistor tester and add a continuity buzzer on it's place
+RadRider33 that design was my first multimeter too. got it like for 6 dollar local currency equivalent like 10 years ago. Mine died sadly (numbers jumping for no reason, no measurements on any range), lead broke somewhere inside. Still have it as my first dead measurement instrument.
Sagan is fantastic. Great to see him getting into that MakerBeam kit. Way to go, and greetings from Seattle, Washington (specifically Kent, Washington)!
When Segan is in his teenage years or so, he'll be able to look up old footage of his early childhood on TH-cam...
Kinda weird if you think about it, the first really "digital" generation post 2010's
+Osmosis Scary. I've got practically nothing from my childhood. Just a couple of photos.
+EEVblog Your son is adorable.
+Osmosis I'm 25 and I even I still find this a bit scary. The oldest footage I have of my childhood is all recorded on cassette tapes and faded images.
+Osmosis i dont know if weird or disturbing how easily everyone will be able to look up all your embarrasing moments digitally at typing speed, in our age you'd have to dig up some old VHS-C tapes(if someone was even filming in the first place) -pray they're labeled properly- and essentially watch the entire thing to find out something or clumsy FFWD, maybe a photo album.
Now with a camera/video in everyones pocket ready to record in seconds, failarmy and yt every blunder with haunt you forever :D
+Osmosis And he'll be reading these very comments. How spooky.
I love when Sagan show up! Very nice!
They sell those multimeters here in the Philippines for 120 peso (2.5 USD). And that's in the mall! So imagine if you bought them in bulk :P
+Gadget Addict less than a dollar in china :-)
www.alibaba.com/product-detail/High-quality-professional-digital-multimeter-DT830B_921274538.html
+Gadget Addict CD-R-KING!!!!! hahahahahaha
My niece is around the same age and she also started going to school 2/3 days ago. Hopefully she's enjoying the experience.
Enjoy him! Time goes so fast. My last one graduates this year, WOW it seems like yesterday. Cheers
Have one of those multimeters for 10 years now and works perfectly. Nowadays I have a Fluke 179 and I like it but to be honest for my needs the cheap China multimeter would do the job perfectly. Highly recommended
Clearly Sagan takes after his mother; his diction is very good ;-)
+James Brown I can't be the father, getting a paternity test immediately!
+EEVblog I don't know, he seems to love your work when you bring him! should be very proud!
By the way did you try Golf and give up username? Story behind it? Please call me at not a? But an explanation point
What a clever boy Sagan is! You must be a very proud dad dave! I'm sure he'll grow up to be as much as a legend as his old man!
the Rossin device that you showed on # 813 is a passive infrared sensor for a burglar alarm. It is intended to be wired in a normally open alarm loop. the battery actually powers the device and i think it should last for ten years . I used some of these probably 30 years ago. will look to see if I have any info on it. Love the Blog. Thanks for what you do.
that cheap multimeter... tell you what its handy for random small jobs and better than a bulb with two wires.
A bulb with two wire is often better for testing automotive circuits.
I have one of those just for continuity and reading voltages on where i don't have any idea of how much tension it is (and don't give a fck if i burn it haha)
@@TheCode-X The gadget is not what you should be concerned about. The worry is about the effects on your person of its explosive disintegration by massive overcurrent.
Speaking of a bulb with two wires I used to have that same setup for testing voltage when I first started out you're doing electrical projects it was one that was handed down to me from another family member.
It was homemade but still in good shape even with the original test leads that probably had been re-soldered a few times originally one was red and one was black but one had to be replaced.
From what I was told and I also had a second one that is made by the same person that had longer leads but had two bulb sockets so that it could be used anywhere from 120 volts up to 220 Ameri fact I remember hearing about in some way somehow possibly from different sources how's that the utility company when connecting up to a residence when running new wiring for overhead lines Wood Lamp out to connections at the service entrance from their wiring to the service entrance whenever first connecting using a setup very similar to that also I still have a continuity tester flashlight that was given to me years ago is still works although I did converted to an LED it still is a nice flashlight also somewhere I still have a few of the old from colored not necessarily chromed but I think one or two are metal C or D cell flashlight I think a couple r c and a couple Rd also have a few lanterns stowed away somewhere that would have used the racial big 6 and 4 volt batteries I'm thinking about converting them some way to recharge mobile maybe you're sealed lead acid and perhaps a built-in power bank?
Although I do have one Lantern or two that had a quarter inch track originally on there one even had two of them perhaps one was added?
So that you could use it with a headlamp in addition to your Lantern and yes the original coil cord is still in good shape believe it or not.
And there was also an area like that could plug into the second Jack.
There was a switch for both receptacles and also a switch on the lights themselves as well.
Can't remember if that was a 6 or 12 volt Lantern but I think that one was 12 it's stashed away somewhere but not where I am right now.
Also have a land foreign pride of similar except it's got a cord and 2 rounded is 1 would Connect into the front of the lantern in place of the Winds and reflector assembly and the other is essentially the head of the lantern that the bulb in reflector assembly goes into to turn it into a hand Lantern from a battery pack type Lantern again it was one that took the large alkaline or whatever it would have either been 6 or 12 volt battery you know when the big Lantern batteries they don't see much anymore.
Also I do have some sealed beam 4.5 volt Lantern bulbs don't even know why I have them are where I got them possibly an old hardware store did they still sold those lights and may have closed down but don't know we're no longer sold the lights who knows just one of those random things I got over there years at places that could get stuff from cheaply where is somebody could have been used for something else and sometimes when something like that would come up I could arrange to get all of them Ford even further reduced price especially if I knew the business on her well in which law of cases I did that I was known for picking up stuff that there's only a few things left an inventory they're getting rid of Good Times those times I'd say.
@@stephenarling1667 yes I would agree I have one of those testers which is actually a modified Automotive work light modified in terms of a jack with test leads and another Jack with alligator clips for battery and our Jack with the cigarette lighter connector I Know Jack with female banana plugs
And also a set of very long coiled test leads with male female banana connectors.
Is that should be in everyone's test kit does extension lights same with alligator clip to Banana plug leads and just about any other type you could think of or come up with even if you make it for one specific test put it in your test kit for lighter you will thank yourself for this.
Also speaking of a bulb and Automotive there's times that I did not have the proper materials or tools to do testing and what I would do would just pick up a pack of pull volt indicator lamps the ones that would be worrying that had the blue green or whatever colored plastic around them that was meant to snap into a hole in a panel and just attaching wires it works plus you had indicators for another project in the end one time I even round up using a switch with a 12-volt bulb in it because I could not get an indicator but I could guess which or it was just a viable I don't remember long time ago but I was in pain and it worked I was able to get whatever it was working it need to be to under right then and there.
Also if I was working on something for somebody and did not have a proper meter or continuity tester available I would go somewhere and get a battery holder and an indicator of some sort with nibia 4 volt bulb and maybe a 4 C or D cell or double A or AAA holder and make a Jerry Reed continuity tester out of it and then of course save for parts for another project later I fixed a hair dryer doing that once all that was wrong was there was a broken piece of wire between two points in the device this was actually not the handheld dryer but a Hood Type dryer a very expensive one and the person used it all the time and wondered if I could try to fix it for them Ameri fact the wire need to be high temperature and that was salvaged from something else that I could not fix during about the same time can't remember what was it may have been either a heater or a toaster or perhaps a little mini countertop stove I had prepared several things for them previously was in about a month's time so can't remember but this was many many years ago probably in excess of 20 years but yet the mind is still sharp pretty much Seems Like Only Yesterday that I got my first electrical tester of any type.
By the way was going through some stuff and found my first actual continuity tester that I had gotten from somewhere yeah sure the batteries were left in it corroded do you know where however once I get cleaned up it's going to live on although I already found a way to replace this the original spring which was corroded into two pieces which was the new spring was actually a salvage spring or something and two metal pieces I think that were a battery contacts for something recently folded over on either end of the spring and also they fit exactly without even stretching the spring or anyting so just pretty cool what you can do or salvage parts and also things that you jerry-rig even for one temporary use just to fix one thing.
That little boy is so awesome and cool....
I used to watch my dad work on electronic projects at his bench. When he went to the electronics store on a saturday it was like christmas! I dont do much with electronics like he did but still enjoy putzing around with things of that nature. I find myself doing more electronics than ever now that I am back into RC Planes and lighting my plastic models as well as my planes and helicopter.
Hah! I thought my mail got lost in the post! Great 2 min teardown! :-) Greetings from Ankara/Turkey.
It's so interesting having Sagan helping you, nothing like a child to help out, they always have interesting comments.. He's quite the geek already, just like dad...
Hi Dave, Love it. My dad 'lent' me one of the Thandar scopes in the early 80's It was branded RS Components (UK) and as I recall it cost just over 100 UK Pounds at the time. It was part of a series that included a matching frequency counter and multimeter. It finally packed up about 10 years ago, and I'm ashamed to admit that I still use the probe that came with it! I used it to trace trigger card faults on thyristor lighting dimmers and the fact it was 'ground' free was really useful. It started displaying the same issues you discovered about 10 years ago and finally died soon after.
Sagan should open a few parcels every week love the little fellas enthusiasm.
Very cool episode, Dave. Sagan is just precious.
Have been trying for years to get those modular beams from Bosch Rexroth, can't find them anywehere and Bosch doesn't even answer to consumer emails. But Sagan is the first kid I have seen putting things back were they where (winding the wire back to the spool) instead of taking everything out! Good job Dave!!!
Seeing Sagan made me nostalgic - I used to teach pre-school, which in the US is for 4-5 year-old children (kindergarten is reserved for 6 year-old). I love their curiosity about the world, which Sagan shows frequently - 'what are these?' 'what is this for?' etc. Fun teaching that age, before they've become too cool to ask questions and become bored with school.
aww thats is too cute... you should include him in more videos. What a good father/son moment. Awesome dave, just awesome.
I've got that multimeter, which is why I was particularly interested in this video. I thought you were going to say it's a death trap. I'll keep it away from the mains per your advice though. I've got another multimeter I can use for that, and I know that one's safer because I actually had to purchase a SEVEN dollar torch to get it.
I've been using that Cen Tech multimeter for several years now, still works like a charm! Mine was free with a dollar purchase of tape. The leads broke at a point, but I fixed them with some solder and hot glue. No problems with the meter itself!
I remember in High school electronics class we a like 7 or 8 of those 7 position Harbor Freight multimeters and two or three Triplett 630-PL meters and almost everyone else preferred to use the Harbor Freight meters but whenever I could I used the the Triplett. I loved those meters.
A white phosphorus version of that oscilloscope CRT was used in some portable TVs during that time.
I can already imagine the teacher calls Dave and telling him "I sent him to play with the other children and after five minutes I saw him taking apart everything and all the kids shouting 'Don't turn it on! Take it apart!' "
Mailbag, the best 49:49 of the week.
Drinking iced coffee and eating crispy doughnuts.
Re: Cen-Tech multimeter.
I bought one of these 6-7 years ago. $3. It has rattled around in the tool box all that time, and always works. Original battery. The transistor tester is useless, but the battery tester is not, I use it and many other features most every day. Recently, the probe wires wore out, and I elected to buy new wires rather than a new meter. For the average person, it is fine. Every value I have been able to cross check is reasonably close.
I agree. I know why he is bitching around. I don't care if it is 9,99 V or 9,998563727363738 V
I have one of these. It doesn't measure anything external, only the values of the internal components. It's useful in that respect.
Keep it away from high voltage, absolutely no protection in it. Otherwise it's great for checking batteries and ultra basic diagnostics.
As someone who barely knows what he's doing it's good to let me know if my better Radio Shack meter is working or if I'm doing something wrong. I bought it for the transistor tester which is not great and because at $3 how can you not.
Sagan is just toooooooo cute. Who was the tall guy next to him though?
+Kevy Just some ugly guy who clearly isn't his father.
+EEVblog his opening had me rolling. Excellent job Sagan!
sagans gonna be a damn good engineer growing up in your lab. that's awesome that he's already interested in it at 4
Really enjoy the mailbag episodes with you two!
Always include him in your videos , I love this kid!
10mhz for that scope is damn good, i got myself a "old" analog scope here with only 1mhz bandwidth. probably with tubes inside havent it taken apart yet.
I have gone through at least 5 of those Cen-Tech multimeters. I have never had to change the battery. They blow up before I get to it. Wear the right gloves and it can be safe enough. The case holds in most of the pieces of the pcb and battery
Thurlby Thandar was a company that joined with Sinclair Research and indeed some of Clives calculators ended up in Thandar cases. They were both in Cambridge of course and there was a fascinating array of product made by that pairing.
The breathalyser is probably a generic flammable gas detector. It consists of 2 wires, one coated with a catalyst, and one not. They are wired with 2 resistors in whetstone bridge configuration. The wires are heated by a small current, but normally remain balanced. If there is alcohol on the breath, the catalyst oxidises it, and adds heat to the catalytic wire which increases in resistance unbalancing the bridge. All you need to do is measure the bridge imbalance and if it is over threshold turn on the light.
So far, I own 4 of those free Harbor Freight Tools multimeters. At first I figured they would be very inaccurate, but was surprised at the accuracy. I also figured they would be unreliable, but so far they're reliable enough for use in non-critical measurements.
I keep one in each vehicle, monitoring the battery voltage, and after several years, they still do a good job. They even give good readings at 30 degrees F below freezing and 120 degrees F.
I've had them read incorrectly about 2 times. I quick rotation of the switch, and they're reliable again. I only use them when I already know what reading to expect, so I can tell if they are off very far.
Not to be fully trusted, but still useful.
It's PIR, I used very similar units made by Racal back in the early 80's. It had an operating life of about 5 years, and used the on board battery. After the unit detected motion, it would "sleep" for a period of time, to save battery life. That unit was clearly a single narrow beam type sensor.
Love those free meters. I have them at several at friends houses. Several here. If one blows up no problem.
The Rossin thing looks exactly like the one my friend had in his house back in the 80s, I think it had a send and receive on either side of the hall way, I remember having to slide under it when we would skip school and go to his room to play video games on the Atari lol
I've bought a nice Amprobe AM550 when I started in EE. Now some time later I needed some more multimeters and I'm on a really tight budget, so I've ordered two of those from ebay. They will do it and for the more precise jobs I'll just use the Amprobe one.
I've been wondering if you would be interested in doing some small side projects for the channel on a regular or semi-regular basis? For example, I think it would be fascinating to see you try to work up your own version of that Thandar portable oscilloscope. Perhaps these little projects could even be given away from time to time. :)
That would be amazing! +1
+James 86 I'd love to see EEVBlog builds, even if it's simple electronics.
+Prehistoric Man Me too, even in simple circuits we can see, and learn good habits that we can use for design electronics devices. :)
+James 86 dave doesn't build anything, he just tears things apart. oh wait, he did build that microcurrent thing... kind of simple though.
Dave used to develop and sell kits. Like the uWatch. But he wrote some time ago, that is a lot of afford and trouble. Even shipping bis uRulers was a mess and that was a plain PCB. I would love to see him continuing the uSupply, but I also understand we he is not.
IIRC the switch on the alco tester is just for the light. To measure your alcohol level, hold the push button depressed until the green led lights up, then blow gently onto the sensor.
"Remember to keep children away." "...bugger that, I'm giving it to Sagan." Dying.
Actually I think Sagan would be better with a fluke meter once he's old enough to be responsible using it of course I would not trust that meter with if I had a son for his own protection and would have him a decent meter for full protection for inputs than all that because people make mistakes when they measure things that's why that production is supposed to be there if he were to blow up a meter she would learn Omar send it about proper testing protocol for example blowing the HRC fuse would let him know that poops I did something I should no not to do instead of having the meter blow up in his hands and possibly mean never able to test any circuit again due to a messed up hand or worse possibly be no longer among the living because of a cheap alternator scratch that multimeter Google you know The Giver of pain and sometimes laughter and other times just frustration LOL.
Hansom young lad .. I really respect you for adopting him !!
They don't practically away, they do just give them away. With a mail/online coupon you just walk in no purchase necessary and show them the coupon and they give it to you free.
Plus 600 volts is considered as HIGH voltage in to US. the breathalizer might need alcohol to work.
great video! He can follow directly in your foot steps.
That kid is going to be among the smartest people in the entire upcoming generation. I hope you can keep showing him how useful this knowledge can be.
Sagan! What an awesome helper.
Those cheap multimeters are perfect for checking battery voltages, or continuity (if your model has that feature). I have dozens of these laying around. I do have a couple good meters but they don't get used unless I need precision. I used one of these recently to diagnose an electrical fault in my car, worked perfect.
Cen-Tech meters are good for solving quick and easy problems, and cheap enough to have everywhere. But I did notice one major problem. As they get older, they start to loose accuracy, especially the ohm meter. Not sure if it's battery related, but the meter is cheaper than a proper 9v battery.
I have the 92020 version of the HF which includes a gorgeous orange backlight and is surprisingly accurate. I would never put 10A through these. So what i did was use all that empty space inside to convert it to a 4-wire tester by putting a good rechargeable lithium ion battery from an old cell phone + powerbank chip + a homemade LM317 100 mA constant current circuit inside, with a 2P connector in place of the 10A jack. Everything else still works off 9V, but I get the most use out of checking USB cables with the 4-wire-on-demand feature I added in conjunction with the 200 mV setting (multiply by 10 for milliohms). I don't know if anyone makes a small portable 4-wire tester like what I now have? I know this multimeter is a joke, but not everybody needs a big knife! A really nice meter for someone who can't afford much.
Not even in kindergarten and he can handle the screwdriver like a pro! :D
I think I may have been like that as a kid judging by what I already knew by the age of five or even 4 for that matter some people say because at that time I was rewiring hundred twenty volt AC lamps yeah I was repairing lamps at 5 years old so yeah I think I got sick and Beat just Maybe Kinda sorta.
Love the Crocodile Dundee knife. "That's not a knife mate. THIS, is a knife."
Bright young lad youve got there! Glad to see him super interested in everything!!
Got one of those multimeters for free from Harbor freight a few years ago, wish I had read the instructions the "do not operate tool under the influence of alcohol or drugs" part is great.
33:45 to 43:30 ... Well done on missing the whole point of those cheap multimeters. Being cheap enough to be classed as disposable it's handy to have a fairly flexible and relatively accurate device of this type in your car, bike, boat, etc where it doesn't matter much if it gets damaged. It's better than risking an expensive one in such potentially unfriendly environments.
29:07 They called that a "Thermal intrusion sensor" if memory serves correctly. I picked one up at an auction in it's box...but threw it away.
Of course I couldn't figure out how to use it? Or just so odd? Please elaborate in a comment
I have maybe ten of these Harbor Freight multimeters, and I LOVE them.
I use them for doing assembly work primarily, and may need to ensure that 12 volts or 24 volts, or whatever is actually present. But may go ten or 20 minutes between uses.
These are the only multimeters I own which actually have an on-off switch So they get used quite a lot.
I have better multimeters which I grab when I need to actually need to measure something.
Better check that wrist strap and make sure that it employs the 1M resistor :D
found this patent about an intrusion detection device from 1974 by J Rossin www.google.com.br/patents/US3839640
note this part: "This invention using a 1% inch diameter concave mirror can easily detect a moving person 25 feet away. Larger mirrors will, of course, detect from greater distances."
Dave I'd suspect that multimeter brand would send you their most accurate product from the test line just to make a scene.
By the way nice find on the patent on Google will read full thing eventually saved it to favorites.
Just a quick skim over it pretty intriguing and interesting that's something quite a bit different than most motion detectors for sure and also the device that you're referring to in his video yes very different but the problem would be must have battery dies would it be able to indicate nurse an issue with the sensor? Maybe if do barristers to get low input sound of a certain parent of false detections the indicators a problem with the sensor or something of course a system designed like that would probably have a way of determining if the sensor had an issue or the battery was getting low but it may have been too early for that but if you're a lot of them I can see if there was no way to indicate if there was a brown with battery or sensor if you have a lot of those it could get confusing or say it was in an awkward to get at place just trying to figure out what was going on I could see that if it had had it replacement batteries in a battery holder both Glow Draw lithium would be better but still something like that being solar powered by a lithium battery in hard-wired into place but an advantage would be you would not need power after detector simplified wiring and hook up for the sensor but it's kind of Niche product I'd say just an odd one in general I doubt they still use things like this or somewhere like that would still be available is with all the advances and more modern systems? But may still be in service somewhere someone out doing something who knows.
Also I I have seen very old motion detectors that were humongous in Old buildings and even Tone Ultra Sonic alarms are basically obsolete even the box that could be set on a shelf self-contained ultrasonic alarm probably from the 50s or 60s still working to this day.
Have Salvage all types of equipment like that for parts and repurposing old alarm systems that were functionally obsolete for who knows how many decades you know the old green box up on the wall it'd be rectangular and probably have a battery in it likely number 9 drawer cell in some cases.
So those were essentially a glorified exit alarm for a door some of them even had the hardware for that accept had a small relay module how do I know this I've seen the door alarm version from the same company and the alarm version from the same company most of the inside is identical.
Sometimes I do work to liberate things for Salvage in others as part of the deal for something that need to be done and sometimes I got more than I bargained for like once almost a whole basement full of old equipment.
Also I did actually couple times use old remote control systems that work for TVs that were ultrasonic and repurpose them for other projects.
Although one of the more interesting remotes I've seen was not ultrasonic or infrared basically a glorified flashlight with a relay that would flash the bulb an each Button had a specific flash pattern and it was repeated I think twice maybe three times to avoid false triggering ingenious but it works and yes there was a push button to use the remote as a flashlight which I thought was just why not.
The remote was a bit bigger than an older garage door remote I think it took 2 C batteries side by side at the bottom of it many years ago.
Also I once saw a toy CD player music box crayon saying it similar to the one that Radio Shack made except it had a remote that basically work the same way which I found out that particular one deliver or not I was able to take the output of that separate circuit board and make it do my bidding can't remember how but I was able to decode it interesting it was two easy dinner face it may have been serial or parallel it seems like Pearl alderman except a few signals put out more than one pint of ones but it seems like the rest of the others would always only be active with one button there was also a word that was active for invalid signals inhibit?
Although I built a CD jukebox system once I got a hold of this equipment that originally used what look like off-the-shelf mini mini disc CD changers except some different controls on a front additional things this weld are on the back more Jack's Imports than you can shake a stick at evidently if you could think of a way to control it it could do it out of the boss parallel port serial port an even individual + 5 to 12 volt triggers for each function seriously definitely some sort of product that was meant to be incorporated into something else I got a lot of these at one time don't remember why I want to fool with them but I did reuse them of course not going to take that part and scrap it when you could build your own jukebox essentially but you got it could be used Standalone and there was a separate remote for Standalone it did not operate any of the other functions or any of that as well not only that they could even be powered by other than line voltage AKA DC and the power supply even Han outputs for other voltages for external are an external connector so basically a prank it was designed to be around designed to be used with whatever application you wanted it to be used for that you might want to control CD playback but yeah mostly look like an summer gear which was strange you think that something like that would be in a rack-mount case but it wasn't but evidently that will available as well strange again.
Also all the audio and everything was run out to multi pin connectors in addition to Indian kid actors and others and with the multiplan connectors they also went through audio switching as well which could be controlled by remote and or other inputs so evidently it could Multiplex or switch audio from one or more of those players to a common output so just one of the weirdest things I've seen along that line of those kind of things but just interesting nonetheless and useful even after the original application was done for I had also a lot of these are spare units as well so don't know where they were so came from where the story but car from someone else there was a hole in my trunks and fousey August he kept a few but the rest not so much also got several years to other people as well that could use them
Also as for the last part of your comment I bet you if it hasn't happened yet it will of course it usually does?
Also remember to chinese-made phone charger I think it was where there was a ridiculous thing about they're hand-tuned or whatever spark gap and all that crap and no words a defective product that had been written up like that was intentional and also and it was chinese-made if I'm not mistaken and it did go by the name that's commonly referred to as Chinese junk from a certain Market can't think of the name of it at this time but it was hilarious and evidently that was actually from the factory and they sent it as a gag but still rather entertaining kind of reverse of what you'd expect but I think they wanted to have a laugh really who knows how long it took them to find one exactly like that so they could do that.
sagans segment intro really made me smile! Good kid!
I Do not toss out cheap DMMs, Use as a DIY>panel meter< or DIY test box, has on /off switch so U can tap your power. -as them 1$ multi-meters make for good DIY custom solo-meter test box, just fix the range for the job u need check the calibration< & add buffer /shunt ..esc. - Also - when I was 8yro I did test the wall outlet with my dad,s analogue meter as most radios at that time , had HT of 400V
We need more EEVBlog assistance from Sagan!
It's basically the standard Mastech DT830B except all the Cen-Tech ones have the battery tester with a switch where as the other DT830 devices usually have the knob control the power and no switch. Some of the Cen-Tech multimeters even have Mastech molded into the plastic of the lead ends. If you're planning on giving it to Sagan, make sure you didn't loose the two ball bearings that are in the knob. I saw them fall out when you were rolling it around.
I got a few of those HFT mulitimeters (for free). I was thinking of taking the thing apart so I could embed the multimeter as a voltmeter in a home brew power supply. I'd have to some how wire the lcd to the board with ribbon cables and short the right lands on the range switch for the desired voltmeter range. I might even be possible to cut the main board down a bit since I might not need all of the circuitry on it, I'd have to trace the layout out and figure it out. The thing just might make a serviceable DC voltmeter for a project.
Dave the super dad! Fun to see how quick your son is progressing,... Within a short time he really needs his one workstation, along Dave2
Hey Dave, did you not show us those beautiful postcards from my fellow colleague Tony / Toni from Deutschland, did you? :)
Loved the mailbag video with Sagan talking!!!
That Rossin device is a "thermal intruder detector'. Basically an early PIR sensor.
Yep
I've had a Cen-Tech meter for several years and surprisingly it still works, mine looks almost identical to the one here except it has a backlight button in the upper left area by the DCV label.
Hooray for the little multimeter.. Fantastic value..fit for purpose ..budget product.. Fills its marketing niche well.. Does not deserve ridicule or scorn.. Dave ... point out the limitations ... evaluate manufacturing considerations.. but showing so much disdain for an engineering, manufacturing and marketing success only lessens your professional credibility........
I think it is nice for Sagan to come along for the ride ,but daddy is driving and needs to focus on the job at hand..
Build a wire spool holder with a mere €100 worth of extruded aluminium profiles.
Hehe, I can just imagine Dave thinking, "okay Sagan is gone, time to get out the knife!"
This is not a knife this is a knife
Those Harbor Freight meters get put to another use: A Field Strength Meter! Conversion article on page 71 of the February 2015 issue of QST Magazine.
You can be an aerodynamicist, a theoretical or particle physicist, an actor, director, a painter or a musician. But, in the end, if you are not a good, dedicated parent, you are not much as a human being.
My respect for you just grew massively. Im 100% sure little Sagan will grow up to be an outstanding human being :) I wish him all the best :)
+vacomments Bollocks.
I like how he takes time to appreciate all the mail when he doesn't really have to, he could easily glance over it and not give a crap
I have such a cheap multimeter for years now, it had to withstand many troubles with me. Shorts ( even with line voltage ), overcurrent in current measurement and so on. The contacts for the probes are worn now and the measurement is incorrect as hell. Well, time to spend another 5 bucks, there good for my needs :)
As others have said the unknown sensor is a PIR type device. The lack of fresnel will just mean the detection area will be very narrow, could be a people counter device.
Those meters are actually fairly good for just having a meter laying around. If you want assurance, don't use it.
I have one of those, this is the multimeter use on construction sites, where it is very likely to get damaged or stolen. If it got stolen or kicked off a building, don't even need to bother about finding it, and its so cheap nobody would bother stealing it, and if they did I wouldn't even care.
Wow, they actually got a trimming pot inside of this one. On couple of these ICL7106 ripoff meters that I've bought in the local shopping mall because they costed less than the 9V battery inside they actually cut costs by replacing trimmer with just a regular resistor... And a bit of plastic cost by omitting the battery chamber and just randomly sticking the battery between PCB and case.
that CTT box don't never gets old, here from Portugal
That "free" multimeter looks like one I borrowed from a friend to help me fix his friend's TV set. Fortunately it was adequate, and it was just a failed fuse with no obvious cause. I had the set working again in under an hour, including going to a shop for the part. Transistor sockets are definite frippery.