ℹ *EPISODE FAQ* • "Is your phototransistor the right part?" Let's just say maybe we'll _see the light_ and try some different options at the start of Part 2. Ad-free early access: patreon.com/perifractic • "The original frame rate was 50 fields per second interlaced not the 25 frames per second you have" That's true. It will serve us well to find the original tape in Thames TV's archives...
I saw you use an IR diode, you can see it because the diode is completely black, it’s actually not black but really deep red plastic, that is probably why it reacted on your phone light because that light is very bright, and some of the light passes through it. but the dark filter around that diode is to filter out normal light, It’s transparent in IR light
I'm betting it's the latter, the field rate. I have a feeling the lack of every other field might be to blame here, and was worried when I noticed a laptop was playing it to a CRT, not an original tape. Hopefully the tape can be found! I think this is very much the issue, but it's hard to know without knowing how fast that dot was supposedly flashing (if it was 50 strobes per second, or 25 strobes per second).
@@bopsop Ohh, good point! I didn't even realize it was an IR photo diode until you mentioned it being opaque. Yes, regular photo diodes do not have IR filters, and a CRT of course does not emit IR.
My father remembers this and built it, have shown him this, he said although you see a square it is actually a series of lines that transmit the data and you have used a IR diode not a photo transistor. It did work but as you show the time was totally impractical, but it was a fun and ground breaking idea at the time, he has still a number of BBCs and ZX spectrums. This has prompted him to think about looking at them again.
The golden age of home computing, where everything was new and when things did work you felt you'd actually achieved something...good to see it's still hard to achieve in the retro world so will make the completion so much sweeter !!
Wonder if anyone got that program working back in the day. hehe Imagine trying to tell the young'uns nowadays to do all techno techno-wizardry that just to grab a program off the TV... I mean TikTik. lol
Channel Four also transmitted software over audio during the morning Schools and Colleges block the day after 4 Computer Buffs went out, I remember sticking my cassette recorder next to the TV speaker and getting a demo of the Melbourne House Spectrum game "Mugsy" for my trouble.
I know you probably already have the true answer, but i'm wondering if that's actually Photo Transistor 🤔to me it looks like an IR Photo Diode due to the color of the component.
I remember on the Dutch television after closing, they sent the software via the audio channels. You had to record it on a cassette and the next morning you had a new C64 program 🙂
Peri, i can say with confidence that outside of the orignal show producers/segment you are the ONLY person to ever attempt this. And if this program plays DOOM on a C64...
@@RetroRecipesI completely understand. This current KR project of mine was my finest moment of “I can get this all wrapped up in two to three weeks” estimation errors. I’m excited to bring it to you, but it’s been tons of extra work- so I totally comprehend. (I’m looking at possibly two to three more weeks to finish up. Oh well. Quality matters!)
9:34 Phototransistors are a dime a dozen and function by changing resistance in response to light, which will then alter the base voltage of the transistor, giving an amplified square wave at the collector. They resemble miniature solar panels, and you could even use a small solar panel (from a garden variety charging garden lamp) if you can focus a light dot onto it. However, it looks like you've acquired an infrared light-emitting diode, which emits light rather than receiving it. To get the desired result, simply replace this component with a phototransistor, adjust the potentiometer, and use your oscilloscope to observe a nice square wave signal generated by the flashing light. On closer look it looks like you do have a phototransistor qsd-123ND designed to pickup infrared light. Buy one for normal white light and you should be good to go.
Not weird or surprising at all... The phototransistor you selected in an IR phototransistor... it has an opaque filter to visible light, that is why it looks black. The CRT is not an IR source so you will get nothing. You need a visible light phototransistor, or you might even be able to use an LED as an input source, perhaps a hi-eff red with a clear body. You'll need to experiment, just hook the LED to your O-scope and see if you can get it to respond.
A CRT is a great source of IR - anything which gives off heat is giving off IR. The issue however is that the IR phototransistor is not a drop in replacement for the regular (visible light) phototransistor - the thresholds between black/white will be extremely different and well beyond what can be compensated for using the schematic as shown. While it would be possible to get working with an IR phototransistor, the far better thing to do is to get a Light Dependent Resistor (LDR) which will perform the same functionality as a typical visible light phototransistor and is what are commonly used today. The schematic might still need some slight adjustments to cater for a different threshold, but it will be in a more realistic and practical range compared to an IR phototransistor and will make troubleshooting far easier - you'd be able to use a regular DMM to detect the difference between black/white from the resistor all by itself, the rest flow from there...
@@sirtra The signal is in the optical range, not IR, and the opaque optical filter was blocking out all visible light except IR, so that would have never worked even if the light was marginally triggering the sensor. I see that you responded to my comment twice and in that response I suggested a phototransistor FTP 100A that I used to make a light pen for my VIC-20 in the 1980's. It used the raster scan registers to detect the timing of the beam... I think I got the design from some magazine, but I built the pen and interfaced it to the DE9 pin Joystick/paddle connector (so long ago I can't recall how I did that.)
Yes, quite satisfying - when they actually ever worked. Most of the time, they were riddled with bugs/misprints and they never ran properly, if at all after hours of typing it all in and more hours de-bugging.
I love this stuff. My wife always shakes her head when i dump hours into getting this stuff to work (to never use it afterwards 😁). But it’s SO much fun to fiddle with it until it suddenly clicks and function, it’s just great. Many regards from Germany, as always! 👋😁
@@RetroRecipes I', 100% with you. As long as you're having fun, it's worthwile doing. My wife knows this and I think she likes seeing me tinkering, she always comes and takes a look and brings me something to drink. At least as long as I don't use the whole weekend for my projects, the kids are more important, obviously. Love your stuff, keep it up! I think your fanbase here in germany is growing with every video 😀
Haha i swear this is a fundamental difference between men and women, it even explains why many men refuse to ask for directions or where something is in a shop (much to the dismay of their partner) Sure, it might take me 10 times as long to find something the first time, but what i learn along the way will typically mean i'll know stuff i otherwise wouldn't and will be able to locate or find something entirely different far quicker in future. It all comes down to whether that future saving will offset the current penalty.. but as long as you're enjoying the ride then even the extra time invested isn't really wasted, it's a recreational activity!! 😁 If you have a baby in your arms though, getting directions is probably the better option... there are times when listening to the missus is advisable.
Gosh, I envy you for your patience. I'd have had to go and lie down multiple times to cope with the frustration. 4 Computer Buffs was an excellent sister programme to Database on ITV. I remember people were invited to send titles for the programme made on their home computers. A wonderful Retro Recipe project. Compelling viewing as always. I hope the wallpapers I sent you will fit with the time travel theme for your own enjoyment. A fantastic job Perifractic.
@@RetroRecipes😂 Okay, I’d like to see the frustration bits now. My frustration edited bits look like Peter Capaldi smashing his fists into the TARDIS console. 💥😁😎
@@RetroRecipes Well, a good lie down can do wonders as Junifracttic demonstrates in your video. That or an extended period of shouting and swearing might help but could upset Babyfractic. So perhaps not.
Takes me back to the days when my faithful Timex Datalink would read flashing data strips from a CRT... There was something magical about those sessions!
Around this time, C4 also went through a phase of broadcasting software as an audio signal alongside the test card (test pattern for Americans) while they were off air during the day. This happened while I was at school, so I programmed my VCR to record it, then dubbed the audio to cassette and took it round to my friend's house (it was Spectrum software and I had an Atari 800). To our astonishment it actually worked, and the software turned out to be the full version of the game Pud Pud.
I don't remember seeing 4 Computer Buffs myself. I do remember that Ceefax (the BBC teletext service) broadcast programs over its pages - hidden in the "extra lines" of the TV broadcast signal. And going back even further there were games and programs transmitted by radio stations. I've been involved behind the scenes on this myself, so I'm looking forward to solving it and watching part 2...
Gen-Z : Points phone at flashing dot... downloads emulator... runs software. Interesting video though. I think my dad recorded the Basicode transmissions waaaaay back, but for some reason the interpreter never worked properly on the ZX Spectrum.
I remember the Swedish state owned radio broadcasting some kind of code for a C64 program sometime in the 80s. I recorded it but could never get it to work on my C64. Probably too poor recording quality, since I probably recorded it on a cheap boom box or something. I can imagine this stuff must've been exponentially more elusive to actually getting the program down to your computer.
This series of videos is the reason I subscribed to Retro Recipes many years ago. The level of commitment to reach the end result is off the scale. More like this please!
If you're just trying to get the program, which might be valuable for trying to see if you're actually getting your hardware to work, you could go directly to the video source and just sample the pixel color at that location on the screen as the signal, then you just need to sync when you sample the pixel and match it to the frame rate. Sample at least at Nyquist sampling rate, so 50 Hz I imagine for a BBC broadcast, then you can extract the actual signal directly, or you can use that to drive a transistor or SCR and send the signal to the C64 over the same pins as the loader program expects. Once you've got that, you can refine the original hardware receiver to get parity and match the expected output.
Nooo, a cliff hanger at the end! Hopefully part 2 will also resolve the 39 year old cliff hanger from the TV show. A cliff hanger to resolve a cliff hanger. I can't take this! 😱😄
I was going to say "I've never heard of no '4 Computer Buffs'!" ... but if it was cancelled that quickly, it's no surprise. I'm going to have to see if I can find some episodes online. From the little clips you show here, it looks absolutely fan-tastic! I love how Channel 4 really tried hard to get the word "for" into as many of their program titles as they could manage. :) Cor... with the nasty scanned and compressed copy of PCW and the (probably) VHS recorded and horribly compressed original program... this REALLY is like archaeology.
Definitely a really cool idea, and very ahead of its time. However, I can definitely see why it didn't catch on as a popular data transmission method. Also, when you first explained the concept, and how nobody knows what the program really was, my first thought was "Man if you did that today and downloaded some mystery program off the TV, you'd either get some sort of ransomware, or get Rick Rolled." How times have changed!
The "Videodat" system from the German "Computer Club" needed more expensive hardware, but it worked. The "Computer Club was very successfull, and after cancelation on WDR TV they continued as "CC2" on TH-cam. It was for over 25 years on real TV, and another 10 years online only. The software was transmitted in the beginning in "Basiccode 2", which made on compatible to almost any system. I don't remember if they still used Basicode 2 in the 1990s, as it was quite outdated then.
I laughed when I saw the guy demonstrate the various stages of the circuit being made. Reminded me of another TV show; "here's one I prepared earlier". Lost on your American viewers but loved by many back home.
Brilliant work! I'm sure I remember this show, as I avidly watched any tech content in the 80s. Such a hilariously convoluted concept, I know you'll make it work somehow! So nice to see PCW magazine there too, I was a reader then with no idea I'd actually be writing for them seven years later!
Thank you Perifractic and Puppyfractic a step back to when life seem less stressful. The excitement of getting a new program in your computer magazine and learning new skill like contacting your friends over the Bulletin Board and packet radio. Thanks you also saying hi to Ladyfractic & Babyfractic.
Anyone home? First time watching. I really love the detail you put into your work! So many references and jokes many (including me!) might not get the first time!! And still having your old TV set and stuff, I mean, nobody puts a baby in a corner, right? ;-)
4 Computer Buffs I recall being a decent computer show, I can also remember the software transmission thing but never built the gadget. Cool episode, thank you.
This is probably the finest cliff hanger TH-cam episode, lol. The inner child in me has wondered for decades what that programme was. I was super excited that I was to finally find out. But no, you shot down my excitement like evil parents cancelling Christmas... I shall hit the refresh button every 5 minutes until part 2 arrives \o/
Y'know, sampling affects video too. It could be that the video CODEC used to compress the show is causing the same issues as the audio CODEC did. Plus, you are assuming that the frame rate of the picture is not being seen by the photo diode. A one second "flash" of the spot on the TV is in fact 25 (PAL) or 29.9(NTSC) flashes per second. Worse, your monitor could be doing more frames due to its higher definition. You could in fact be getting 60 flashes per second? And then there's the issues you had converting your monitor to 60hz line frequency. The broadcast was designed for a PAL TV set with 25 frames a second at 50 Hz. In your video snippets you VOX a bit where the presenter says "and we think we have it right now". this suggests to me that it did not at first work. Can't wait for part 2!!
The monitor is my original 50Hz UK TV that I had since I was a kid (as mentioned in the video) and we'll see in Part 2 that it's refreshing at 50Hz. But you're on the right track to what might be the real issue re the compression of the video when it was put on TH-cam ;)
in the 70s I used to make things with LDRs even managed to send music over 6 inches with a bulb attached to a radio speaker and the LDR attached to the amp as the receiver. It was the good old days at the ripe old age of 13 lol.
FIIIINE. Take my sub. :) This is right up my alley. I was so involved with computers back in the day but cant stand programming in the traditional sense. The loops and hoops I built to short-step programming was, well, impressive for the time. Keep up the fine work!
You could buy a whole teletext demodulator for a beeb, and there were special pages on late night bbc2? which were software. I actually did it a couple of times. It never worked for me, but I was in rural Cornwall at the time and the signal wasn't great. I have no idea why dad's girlfriend of the day had a beeb teletext unit but whatever. It was fun to play with.
I miss my SX64. I mean, I miss the experiences of being able to spend endless hours writing software just for enjoyment and exploration. Now I just go to work, the work made possible by that background.
just...such a weird feeling watching you open that box and pull out a disk... I guess nostalgia covers it, but it is so much more than that. I honestly miss the excitement of learning how to program on my 64... and dialing into BBSs in the middle of the night, finding new games, etc. Thanks for doing this stuff, Christian.
@RetroRecipes well, I have been a software engineer (professionally) for 25 years. I haven't felt that kind of excitement in a long time. I love what I do, for sure...but it will never be like Jr. High again!
Remember this very well. Was presented by Tony Bastable and Jane Ashton, with the legendary Guy Kewney. Sister show was called Database and ran for more than once season (I think).
Just a thought that you likely have already thought, can't you take a picture of that program in the magazine, run that pic through google translate and get all the text, copy that into a text file and put that on a floppy to get it into the c64? Seems like it would be less hassle than typing all that, for me at least.
LGR did a video on the “Danmere Backer VHS Hard Drive Backup System” I wonder if broadcasting that signal would have allowed viewers to download data/programs. Same with Technology Connections video on Sony’s PCM-701 which did the same but with audio data.
To make a phototransistor we used to grind off a metal cap of a can-style transistor to expose a crystal of the above-mentioned transistor to the light. This is how I made my very first light-pen for an MSX computer. A de-capping so to say long before it became a mainstream.
I really enjoy these retro-tech episodes, where you revive some cool aftermarket gizmo that wowed everyone at the time (me included!) I know this was a frustrating one for you, but I'm eagerly awaiting the conclusion. Even if it doesn't work I'll look forward to the next one.
I just remembered that there was a device for the Amiga that could transfer floppies to VCR tapes. Video Backup System, I think it used less parts than this project. It seems to me that you should be able to isolate the flashing dot data straight from the video signal with the proper filter and timing. You could possibly also use a solar cell as the receiver. Apparently they can generate audio signals from light.
This was beautiful! It reminded me of a project I'd built on the Atari ST for a wefax receiver. Wefax was an old method of delivering satellite images and you could use your ST to decode these images. IIRC, it was some sort of RLE encoding and a stop/end sequence.
I would have been only 4 years old at the time this was broadcast. I did have a ZX Spectrum, but back then I didn't have the skills to build the hardware and interface it to the spectrum. If only this had been broadcast when I was a teenager - I'd have been right into it!
Reminds me of a special message Isao Tomita recorded on his 1978 Bermuda Triangle album. You had to decode it using something called Tarbel...pretty damn obscure...
Around similar time to this there was some programs transmitted as audio while BBC2 showed teletext around midnight. I recorded it, it was the game PudPud for the zx spectrum.
That was a really cool! I was born in '82 but, never got to experience the Commodore 64 (Or any of the other machines) until the late 90s. I was either using my old 386 or Tandy 1400. My friend did run a BBS so, I got to experience that and play some games which was nice. It seems like the UK had amazing computer tech shows going on, around that time! I know the US had something similar but, I doubt it had projects like what you were trying to build. Anyways, that was a great video!
Great video, but really nice touch with the many 1985 mentions and then when you are standing on a PCB you are wearing Nike Power Laces and the time stamp matched Doc Browns first experiment time and date at Lone Quick-Shot-Turbo Mall.
You use the diode dinkus. It would have been better off with a CDs You saw how the diode reacted when you didn't have any juice applied. That's how opto-isolators work. Take that output from the diode put it to a transistor to amplify and you're in business. This is actually one of my favorite pieces of spycraft. MY dad showed me this when he was working at the Defense Language Institute. Turns out people were broadcasting information via television shows but you needed to know where to pay attention
How did I only just discover this channel??? Subscribed! Great video thank you for the time travel. I also love all your simple vfx. I even love how you left a little dirty chroma green at your feet. Legit retro.
I am weirdly invested now in seeing where this goes (if anywhere)...congrats on the compelling content...story well told and great production values! (I would have run it on the Beeb Model B however, but that was my first computer,,,(
my Farther and I built one!! It was on TV as you state, I thought it was BBC1, we did our best to record what worked like a light pen to download the prog from the TV signal, 40+ years ago I seem to remember it did something, what thing I have no idea now!! Just wanted to say. I DID IT :)
Apparently BBC did a version too. If by chance you have a photo of what you built I'd love to show it in Part 2. You can upload at retrorecip.es/submit
@@RetroRecipes oh, wow, a photo? 40+ years later, sadly no. however I may just be able to find a hand drawn schematic for it. it's that or it's for a light pen.
No memory of this show, but do recall Database, an almost identical show that aired a year earlier on ITV, complete with the same hosts. Pretty much the only difference between the two, as far as I can tell, is the dot and hardware build. Database did transmit software, but only via audio. I used to video the show, and it took several hours, plus multiple blank audio tapes, before I was able to get a workable copy of a ZX81 program they'd sent.
I remember this. I'm sure I tried to use my Spectrum with a light pen to download the program. My middle aged memory doesn't recall if I was successful. Great project this totally got my attention. Aaand you said you were 12, we're the same age !
Fantastic video! The whole process was absolutely mesmerizing and I loved the suspense that built up until the very end. It's a real shame that we couldn't see what was actually recorded. I’d love to try something like this and I can’t wait to see part two!
At that time, we had a very similar TV programme in Germany that also occasionally did such kind of things. The WDR Computerclub. I think the programme ran until 2002 and one of the original presenters is still active on TH-cam today.
I remember that show going out! I never tried to build the equipment but I do recall some things about it. The part nobody could find at the time was the rubber suction cup you needed to stick to your TV screen. Also I seem to recall the flashing cursor thing was transmitted over other programs on the channel because it took so long to actually broadcast anything that way. I think your problem may be that even when a CRT television is showing a black screen, the phosphor is still illuminated to some degree. Try the reader on a copy of the show playing on an OLED tv, where black is truely black and that might work. To be honest though, I never heard of anybody being successful with it back in the day. Also an interesting fact about Thames TV who made that show. I was present at their last but one recording ever made at their famous studios at Teddington Lock. It was the sitcom "Not Going Out" where lee proposes to Lucy.
Believe it or not I had the same trouble finding a suction cup. These days they're only transparent, which will let outside light in. The one in the video description is the best compromise.
@@RetroRecipes I can't remember what they suggested trying for the suction cup back in the day, but I do think they came back to the issue at some point.
That photo-diode looks like its an infra-red job, it won't work at all well with a TV screen. Visible light ones have clear lenses, infrared ones appear black to the eye, but are actually transparent to infrared light. The ones you have are probably intended to receive IR remote control signals etc.
6:42 Don't forget that PAL CRTs frame rate would have been 50fps when originally broadcast so you would be missing a few frames or the frames might be merge together in the low quality transfer you have.
True. Even if the video file is 50 fps, deinterlacing of the source plus the setup with the computer doing playback might cause issues. The best bet for it to work is playing the show in its original 576i50 straight into the monitor.
This video reminded me of one of the most coolest tech that I used to own as a kid. It was a ‘Wheel of Fortune’ game. It was just a simple blue box with a QWERTY keyboard and a multi line LCD display. The amazing part of this device is that it literally allows you to play along with real contestants on the actual gameshow when it airs at night. When you tune in to the nightly Wheel Of Fortune program and Pat Sajak has a puzzle in play, you’d point the toy at the TV screen and through the very analog scanlines in your CRT, the device would ‘download’ the puzzle, and at home, you’d be playing the exact puzzle that the contestants are playing through this device! The device wasn’t completely reliant on the TV show; it had hundreds of built in puzzles you can solve when you play with the device ‘offline’ As a kid, that absolutely astounded me.
Moving away from the actual subject for a moment. I'm quietly chuckling at the particular moment from CP2077 that you threw in. Jet set willy! Ahem.. Moving right along.
![Shareปลาวาฬ ส่งท้าย SS1 พาเปียโน ขึ้น Ferrari ก่อนไปขาย แลก Nissan l [Nickynachat]](http://i.ytimg.com/vi/KAknGkTNIvg/mqdefault.jpg)
ℹ *EPISODE FAQ*
• "Is your phototransistor the right part?" Let's just say maybe we'll _see the light_ and try some different options at the start of Part 2. Ad-free early access: patreon.com/perifractic
• "The original frame rate was 50 fields per second interlaced not the 25 frames per second you have" That's true. It will serve us well to find the original tape in Thames TV's archives...
Try a light pen?
Seen the light of the correct frequency? 🤔😄
I saw you use an IR diode, you can see it because the diode is completely black, it’s actually not black but really deep red plastic, that is probably why it reacted on your phone light because that light is very bright, and some of the light passes through it. but the dark filter around that diode is to filter out normal light, It’s transparent in IR light
I'm betting it's the latter, the field rate. I have a feeling the lack of every other field might be to blame here, and was worried when I noticed a laptop was playing it to a CRT, not an original tape. Hopefully the tape can be found! I think this is very much the issue, but it's hard to know without knowing how fast that dot was supposedly flashing (if it was 50 strobes per second, or 25 strobes per second).
@@bopsop Ohh, good point! I didn't even realize it was an IR photo diode until you mentioned it being opaque. Yes, regular photo diodes do not have IR filters, and a CRT of course does not emit IR.
My father remembers this and built it, have shown him this, he said although you see a square it is actually a series of lines that transmit the data and you have used a IR diode not a photo transistor. It did work but as you show the time was totally impractical, but it was a fun and ground breaking idea at the time, he has still a number of BBCs and ZX spectrums. This has prompted him to think about looking at them again.
The golden age of home computing, where everything was new and when things did work you felt you'd actually achieved something...good to see it's still hard to achieve in the retro world so will make the completion so much sweeter !!
Wonder if anyone got that program working back in the day. hehe Imagine trying to tell the young'uns nowadays to do all techno techno-wizardry that just to grab a program off the TV... I mean TikTik. lol
Channel Four also transmitted software over audio during the morning Schools and Colleges block the day after 4 Computer Buffs went out, I remember sticking my cassette recorder next to the TV speaker and getting a demo of the Melbourne House Spectrum game "Mugsy" for my trouble.
I’ve been released from temporal prison! Just finished 10,000 years in a hyperbolic cell. I thought the sentence was a bit harsh.
Welcome back to the real world Shtunners! Don't do it again!
I know you probably already have the true answer, but i'm wondering if that's actually Photo Transistor 🤔to me it looks like an IR Photo Diode due to the color of the component.
uxcell 20pcs Photosensitive Diode Photodiodes Light Sensitive Sensors,3mm Clear Flat Head Receiver Diode
@@RonLaws that was my guess as well.
@@meeder78 is the TV remote receiver, the parts that in the TV or DVD player etc. etc. ? not the handset remote part?
If things get really desperate he could always try a solar cell!
I agree, looks like a transmitting IR diode. You probably need a different diode or transistor.
I remember on the Dutch television after closing, they sent the software via the audio channels. You had to record it on a cassette and the next morning you had a new C64 program 🙂
Peri, i can say with confidence that outside of the orignal show producers/segment you are the ONLY person to ever attempt this. And if this program plays DOOM on a C64...
Would you believe already at least 2 people have come forward that tried it too. Nobody succeeded though.
Old school RR episode with classic incidental music and a retro-high tech conundrum. I love this stuff!!!!! ❤
🙌 This is what happens when I get over excited about a particular project 😅
@@RetroRecipesI completely understand. This current KR project of mine was my finest moment of “I can get this all wrapped up in two to three weeks” estimation errors. I’m excited to bring it to you, but it’s been tons of extra work- so I totally comprehend. (I’m looking at possibly two to three more weeks to finish up. Oh well. Quality matters!)
Yes yes and more yes! I can’t believe how nostalgic I am about something I started watching less than 5 years ago 🥲🥲
And showing how to shut her up at 20:55 ha-ha
You've upped your editing game so much since I subscribed! you're one of the best channels on YT for old tech and related ish.
❤
Thank you for your kind words! Means a lot 👍🕹
9:34 Phototransistors are a dime a dozen and function by changing resistance in response to light, which will then alter the base voltage of the transistor, giving an amplified square wave at the collector. They resemble miniature solar panels, and you could even use a small solar panel (from a garden variety charging garden lamp) if you can focus a light dot onto it. However, it looks like you've acquired an infrared light-emitting diode, which emits light rather than receiving it. To get the desired result, simply replace this component with a phototransistor, adjust the potentiometer, and use your oscilloscope to observe a nice square wave signal generated by the flashing light. On closer look it looks like you do have a phototransistor qsd-123ND designed to pickup infrared light. Buy one for normal white light and you should be good to go.
I wondered the same about it being an IR sensor. Good call.
Not weird or surprising at all... The phototransistor you selected in an IR phototransistor... it has an opaque filter to visible light, that is why it looks black. The CRT is not an IR source so you will get nothing. You need a visible light phototransistor, or you might even be able to use an LED as an input source, perhaps a hi-eff red with a clear body. You'll need to experiment, just hook the LED to your O-scope and see if you can get it to respond.
See pinned comment
A CRT is a great source of IR - anything which gives off heat is giving off IR.
The issue however is that the IR phototransistor is not a drop in replacement for the regular (visible light) phototransistor - the thresholds between black/white will be extremely different and well beyond what can be compensated for using the schematic as shown.
While it would be possible to get working with an IR phototransistor, the far better thing to do is to get a Light Dependent Resistor (LDR) which will perform the same functionality as a typical visible light phototransistor and is what are commonly used today.
The schematic might still need some slight adjustments to cater for a different threshold, but it will be in a more realistic and practical range compared to an IR phototransistor and will make troubleshooting far easier - you'd be able to use a regular DMM to detect the difference between black/white from the resistor all by itself, the rest flow from there...
A "Cadmium sulphide (CdS) light dependent resistor cell" to be exact, searching that will bring up the component he'll need
@@sirtra The signal is in the optical range, not IR, and the opaque optical filter was blocking out all visible light except IR, so that would have never worked even if the light was marginally triggering the sensor. I see that you responded to my comment twice and in that response I suggested a phototransistor FTP 100A that I used to make a light pen for my VIC-20 in the 1980's. It used the raster scan registers to detect the timing of the beam... I think I got the design from some magazine, but I built the pen and interfaced it to the DE9 pin Joystick/paddle connector (so long ago I can't recall how I did that.)
From a computer operator way back to 1979.. WOW.
Those were the days, you bring back great times. i watched without blinking lol
I miss those days of trying programs from the magazines.
Yes, quite satisfying - when they actually ever worked. Most of the time, they were riddled with bugs/misprints and they never ran properly, if at all after hours of typing it all in and more hours de-bugging.
@@FMFGUF funny thing is, i kinda had a knack for troubleshooting code. At one time in my life I actually enjoyed it. Now days its lost knowledge.
4:38 "This is a dog" XD
I love this stuff. My wife always shakes her head when i dump hours into getting this stuff to work (to never use it afterwards 😁). But it’s SO much fun to fiddle with it until it suddenly clicks and function, it’s just great. Many regards from Germany, as always! 👋😁
If it makes you happy then it's absolutely worthwhile!
@@RetroRecipes I', 100% with you. As long as you're having fun, it's worthwile doing. My wife knows this and I think she likes seeing me tinkering, she always comes and takes a look and brings me something to drink. At least as long as I don't use the whole weekend for my projects, the kids are more important, obviously. Love your stuff, keep it up! I think your fanbase here in germany is growing with every video 😀
@@erebostd That's so sweet of her
Do what you love, do more of it, do it until there is no more time left for you, this is the meaning of life
Haha i swear this is a fundamental difference between men and women, it even explains why many men refuse to ask for directions or where something is in a shop (much to the dismay of their partner)
Sure, it might take me 10 times as long to find something the first time, but what i learn along the way will typically mean i'll know stuff i otherwise wouldn't and will be able to locate or find something entirely different far quicker in future.
It all comes down to whether that future saving will offset the current penalty.. but as long as you're enjoying the ride then even the extra time invested isn't really wasted, it's a recreational activity!! 😁
If you have a baby in your arms though, getting directions is probably the better option... there are times when listening to the missus is advisable.
Gosh, I envy you for your patience. I'd have had to go and lie down multiple times to cope with the frustration.
4 Computer Buffs was an excellent sister programme to Database on ITV. I remember people were invited to send titles for the programme made on their home computers.
A wonderful Retro Recipe project. Compelling viewing as always.
I hope the wallpapers I sent you will fit with the time travel theme for your own enjoyment.
A fantastic job Perifractic.
Thanks! I edited out the parts where I had to go and lie down 😅
@@RetroRecipes😂 Okay, I’d like to see the frustration bits now. My frustration edited bits look like Peter Capaldi smashing his fists into the TARDIS console. 💥😁😎
@@RetroRecipes Well, a good lie down can do wonders as Junifracttic demonstrates in your video.
That or an extended period of shouting and swearing might help but could upset Babyfractic. So perhaps not.
Takes me back to the days when my faithful Timex Datalink would read flashing data strips from a CRT... There was something magical about those sessions!
Dude you're like computer Bob Ross, I'm here for it!❤❤❤❤
It's just a happy little accident 🎨👍🕹
Thinking of you guys. Hope the family is happy and healthy. Puppy too.
Theres hidden scene in 0:08 Microsoft Sidewinder Gamepad what i founded it Thanks to Retro Recipes. Microsoft are best since 1998-1999!
Around this time, C4 also went through a phase of broadcasting software as an audio signal alongside the test card (test pattern for Americans) while they were off air during the day. This happened while I was at school, so I programmed my VCR to record it, then dubbed the audio to cassette and took it round to my friend's house (it was Spectrum software and I had an Atari 800). To our astonishment it actually worked, and the software turned out to be the full version of the game Pud Pud.
I don't remember seeing 4 Computer Buffs myself. I do remember that Ceefax (the BBC teletext service) broadcast programs over its pages - hidden in the "extra lines" of the TV broadcast signal. And going back even further there were games and programs transmitted by radio stations.
I've been involved behind the scenes on this myself, so I'm looking forward to solving it and watching part 2...
Thanks for your help behind the scenes 😉
Gen-Z : Points phone at flashing dot... downloads emulator... runs software.
Interesting video though. I think my dad recorded the Basicode transmissions waaaaay back, but for some reason the interpreter never worked properly on the ZX Spectrum.
I remember the Swedish state owned radio broadcasting some kind of code for a C64 program sometime in the 80s. I recorded it but could never get it to work on my C64. Probably too poor recording quality, since I probably recorded it on a cheap boom box or something. I can imagine this stuff must've been exponentially more elusive to actually getting the program down to your computer.
Computer programs from your TV was the stuff of dreams, please make it work!
Get that retro photo sensor from India and do a part 2. You have me super curious now. Don’t leave me hanging…
On it!
@@RetroRecipesuxcell 20pcs Photosensitive Diode Photodiodes Light Sensitive Sensors,3mm Clear Flat Head Receiver Diode
You can verify by pointing an IR remote at it while observing from the osiliscope.
@@turbofroggy Many thanks. Keep in mind I'm somewhat ahead of where this video leaves us 😉
That pupper is the best office manager ever.
i dont know why but iv always loved the idea of merging old and new tech. its like the more things change the more they stay the same
Well, you got my sub. Great job on this video man. I can tell you put a lot of work into them. This wasn't just a video. It's more like a TV show.
Thank you for your kind words! Means a lot 👍🕹
This series of videos is the reason I subscribed to Retro Recipes many years ago. The level of commitment to reach the end result is off the scale. More like this please!
the woman at 21:04 is so 80's 💞👍👍
I just love how much fun you are clearly having making these videos. 🥰
If you're just trying to get the program, which might be valuable for trying to see if you're actually getting your hardware to work, you could go directly to the video source and just sample the pixel color at that location on the screen as the signal, then you just need to sync when you sample the pixel and match it to the frame rate. Sample at least at Nyquist sampling rate, so 50 Hz I imagine for a BBC broadcast, then you can extract the actual signal directly, or you can use that to drive a transistor or SCR and send the signal to the C64 over the same pins as the loader program expects. Once you've got that, you can refine the original hardware receiver to get parity and match the expected output.
And having now watched the follow up, spoilers, that's basically how this was solved, but doing it directly from the raw tape video feed.
Nooo, a cliff hanger at the end! Hopefully part 2 will also resolve the 39 year old cliff hanger from the TV show. A cliff hanger to resolve a cliff hanger. I can't take this! 😱😄
Ah bugger. Look forward to seeing this working. Cheers
I was going to say "I've never heard of no '4 Computer Buffs'!" ... but if it was cancelled that quickly, it's no surprise. I'm going to have to see if I can find some episodes online. From the little clips you show here, it looks absolutely fan-tastic!
I love how Channel 4 really tried hard to get the word "for" into as many of their program titles as they could manage. :)
Cor... with the nasty scanned and compressed copy of PCW and the (probably) VHS recorded and horribly compressed original program... this REALLY is like archaeology.
Definitely a really cool idea, and very ahead of its time. However, I can definitely see why it didn't catch on as a popular data transmission method. Also, when you first explained the concept, and how nobody knows what the program really was, my first thought was "Man if you did that today and downloaded some mystery program off the TV, you'd either get some sort of ransomware, or get Rick Rolled." How times have changed!
The pupper yawns in the beginning 🥹🥹🥹😭😭😭
The "Videodat" system from the German "Computer Club" needed more expensive hardware, but it worked. The "Computer Club was very successfull, and after cancelation on WDR TV they continued as "CC2" on TH-cam. It was for over 25 years on real TV, and another 10 years online only. The software was transmitted in the beginning in "Basiccode 2", which made on compatible to almost any system. I don't remember if they still used Basicode 2 in the 1990s, as it was quite outdated then.
Peri, you put so much effort into your videos. They're absolutely wonderful and top notch. Cheery-o!
I laughed when I saw the guy demonstrate the various stages of the circuit being made. Reminded me of another TV show; "here's one I prepared earlier". Lost on your American viewers but loved by many back home.
What? Why did you think a reference to a cooking show would be lost on us Americans? LOL.
Brilliant work! I'm sure I remember this show, as I avidly watched any tech content in the 80s. Such a hilariously convoluted concept, I know you'll make it work somehow! So nice to see PCW magazine there too, I was a reader then with no idea I'd actually be writing for them seven years later!
Thank you Perifractic and Puppyfractic a step back to when life seem less stressful. The excitement of getting a new program in your computer magazine and learning new skill like contacting your friends over the Bulletin Board and packet radio. Thanks you also saying hi to Ladyfractic & Babyfractic.
Will do! A step back... to 1985!
Anyone home? First time watching. I really love the detail you put into your work! So many references and jokes many (including me!) might not get the first time!! And still having your old TV set and stuff, I mean, nobody puts a baby in a corner, right? ;-)
4 Computer Buffs I recall being a decent computer show, I can also remember the software transmission thing but never built the gadget. Cool episode, thank you.
That whole childhood desk setup gives me serious "Ready Player One" vibes. (the actual book, not the movie)
This is probably the finest cliff hanger TH-cam episode, lol. The inner child in me has wondered for decades what that programme was. I was super excited that I was to finally find out. But no, you shot down my excitement like evil parents cancelling Christmas... I shall hit the refresh button every 5 minutes until part 2 arrives \o/
Y'know, sampling affects video too. It could be that the video CODEC used to compress the show is causing the same issues as the audio CODEC did. Plus, you are assuming that the frame rate of the picture is not being seen by the photo diode. A one second "flash" of the spot on the TV is in fact 25 (PAL) or 29.9(NTSC) flashes per second. Worse, your monitor could be doing more frames due to its higher definition. You could in fact be getting 60 flashes per second? And then there's the issues you had converting your monitor to 60hz line frequency. The broadcast was designed for a PAL TV set with 25 frames a second at 50 Hz. In your video snippets you VOX a bit where the presenter says "and we think we have it right now". this suggests to me that it did not at first work. Can't wait for part 2!!
The monitor is my original 50Hz UK TV that I had since I was a kid (as mentioned in the video) and we'll see in Part 2 that it's refreshing at 50Hz. But you're on the right track to what might be the real issue re the compression of the video when it was put on TH-cam ;)
in the 70s I used to make things with LDRs even managed to send music over 6 inches with a bulb attached to a radio speaker and the LDR attached to the amp as the receiver. It was the good old days at the ripe old age of 13 lol.
Tinker tinker tinker, I love it! Looking forward to part 2.
This is such an awesome experiment. Nothing likes this would ever be possible again, too bad it wasn't actually broadcasted when they could.
FIIIINE. Take my sub. :)
This is right up my alley. I was so involved with computers back in the day but cant stand programming in the traditional sense. The loops and hoops I built to short-step programming was, well, impressive for the time.
Keep up the fine work!
I remember this ....did Ceefax do the same thing ?( Good to see Thames ID again - Miss those old ITV local stations , Loved the LWT one )
You could buy a whole teletext demodulator for a beeb, and there were special pages on late night bbc2? which were software. I actually did it a couple of times. It never worked for me, but I was in rural Cornwall at the time and the signal wasn't great. I have no idea why dad's girlfriend of the day had a beeb teletext unit but whatever. It was fun to play with.
I miss my SX64. I mean, I miss the experiences of being able to spend endless hours writing software just for enjoyment and exploration. Now I just go to work, the work made possible by that background.
4:38 “this is a dog” great observation
just...such a weird feeling watching you open that box and pull out a disk... I guess nostalgia covers it, but it is so much more than that. I honestly miss the excitement of learning how to program on my 64... and dialing into BBSs in the middle of the night, finding new games, etc. Thanks for doing this stuff, Christian.
That's really interesting and lovely feedback. What do you think it is beyond the nostalgia of seeing that action?
@RetroRecipes well, I have been a software engineer (professionally) for 25 years. I haven't felt that kind of excitement in a long time. I love what I do, for sure...but it will never be like Jr. High again!
Remember this very well. Was presented by Tony Bastable and Jane Ashton, with the legendary Guy Kewney. Sister show was called Database and ran for more than once season (I think).
Just a thought that you likely have already thought, can't you take a picture of that program in the magazine, run that pic through google translate and get all the text, copy that into a text file and put that on a floppy to get it into the c64? Seems like it would be less hassle than typing all that, for me at least.
I think he was trying to "stay in the moment" here, not in 2024.
That was my thoughts... But I am lazy... I suppose he wanted to revisit being a kid
LGR did a video on the “Danmere Backer VHS Hard Drive Backup System” I wonder if broadcasting that signal would have allowed viewers to download data/programs.
Same with Technology Connections video on Sony’s PCM-701 which did the same but with audio data.
Sure glad I saw part 2 video to realize I had not watched this one yet... Bigger project than any of us expected!
Oh man. Computing was such an adventure back in the day. Remember user groups?
To make a phototransistor we used to grind off a metal cap of a can-style transistor to expose a crystal of the above-mentioned transistor to the light. This is how I made my very first light-pen for an MSX computer. A de-capping so to say long before it became a mainstream.
I really enjoy these retro-tech episodes, where you revive some cool aftermarket gizmo that wowed everyone at the time (me included!) I know this was a frustrating one for you, but I'm eagerly awaiting the conclusion. Even if it doesn't work I'll look forward to the next one.
I recall back in the day, brightness was key. You had to mess around a lot to get it just right.
What an innovative concept for a TV show.
I just remembered that there was a device for the Amiga that could transfer floppies to VCR tapes. Video Backup System, I think it used less parts than this project. It seems to me that you should be able to isolate the flashing dot data straight from the video signal with the proper filter and timing. You could possibly also use a solar cell as the receiver. Apparently they can generate audio signals from light.
CDS cell
Love your patience and dedication...
I would of given up long ago.
I would have given up long ago too! 😁
Exciting stuff! Can't wait for episode 2!
This was beautiful! It reminded me of a project I'd built on the Atari ST for a wefax receiver. Wefax was an old method of delivering satellite images and you could use your ST to decode these images. IIRC, it was some sort of RLE encoding and a stop/end sequence.
I would have been only 4 years old at the time this was broadcast. I did have a ZX Spectrum, but back then I didn't have the skills to build the hardware and interface it to the spectrum. If only this had been broadcast when I was a teenager - I'd have been right into it!
That dog thinks you're insane standing there alone talking to "yourself"
Reminds me of a special message Isao Tomita recorded on his 1978 Bermuda Triangle album. You had to decode it using something called Tarbel...pretty damn obscure...
Yes! This is the RR I have been missing! Loved it! I'm looking forward to Part 2.
Thanks! These episodes are much more difficult to make and much more time-consuming, but they will always be on the roster
Around similar time to this there was some programs transmitted as audio while BBC2 showed teletext around midnight.
I recorded it, it was the game PudPud for the zx spectrum.
That was a really cool! I was born in '82 but, never got to experience the Commodore 64 (Or any of the other machines) until the late 90s. I was either using my old 386 or Tandy 1400. My friend did run a BBS so, I got to experience that and play some games which was nice. It seems like the UK had amazing computer tech shows going on, around that time! I know the US had something similar but, I doubt it had projects like what you were trying to build. Anyways, that was a great video!
"We download massive games in minutes"
Me: Downloading peggle for 3 hours
Great video, but really nice touch with the many 1985 mentions and then when you are standing on a PCB you are wearing Nike Power Laces and the time stamp matched Doc Browns first experiment time and date at Lone Quick-Shot-Turbo Mall.
And the hoverboard heat sink had me laughing.
Good eye!
You use the diode dinkus.
It would have been better off with a CDs
You saw how the diode reacted when you didn't have any juice applied.
That's how opto-isolators work.
Take that output from the diode put it to a transistor to amplify and you're in business.
This is actually one of my favorite pieces of spycraft.
MY dad showed me this when he was working at the Defense Language Institute.
Turns out people were broadcasting information via television shows but you needed to know where to pay attention
Reminds me of when I made my Amstrad CPC6128 send and receive an email. Could not put it down ……..
Great stuff RR.
How did I only just discover this channel??? Subscribed! Great video thank you for the time travel. I also love all your simple vfx. I even love how you left a little dirty chroma green at your feet. Legit retro.
I am weirdly invested now in seeing where this goes (if anywhere)...congrats on the compelling content...story well told and great production values! (I would have run it on the Beeb Model B however, but that was my first computer,,,(
my Farther and I built one!! It was on TV as you state, I thought it was BBC1, we did our best to record what worked like a light pen to download the prog from the TV signal, 40+ years ago I seem to remember it did something, what thing I have no idea now!! Just wanted to say. I DID IT :)
Apparently BBC did a version too. If by chance you have a photo of what you built I'd love to show it in Part 2. You can upload at retrorecip.es/submit
@@RetroRecipes oh, wow, a photo? 40+ years later, sadly no. however I may just be able to find a hand drawn schematic for it. it's that or it's for a light pen.
Love these sort of experiments! Thanks for doing them for us😊
I've heard of Duck Typing but this Puppy Typing thing seems interesting
your room looks insane and just looks 1980's. Id dream of that.
No memory of this show, but do recall Database, an almost identical show that aired a year earlier on ITV, complete with the same hosts.
Pretty much the only difference between the two, as far as I can tell, is the dot and hardware build. Database did transmit software, but only via audio.
I used to video the show, and it took several hours, plus multiple blank audio tapes, before I was able to get a workable copy of a ZX81 program they'd sent.
A Saturday morning Perifractic project video. Definitely a welcomed blast from the past.
Where is my Capt Crunch?!??!
Something comforting about the sound of an old disc drive work.
Even today that’s a push to do but back in the 80s 😂
I remember this. I'm sure I tried to use my Spectrum with a light pen to download the program. My middle aged memory doesn't recall if I was successful. Great project this totally got my attention.
Aaand you said you were 12, we're the same age !
Forget it, just load up Buggy Boy instead!
Fantastic video! The whole process was absolutely mesmerizing and I loved the suspense that built up until the very end. It's a real shame that we couldn't see what was actually recorded. I’d love to try something like this and I can’t wait to see part two!
Thanks so much! Imagine how I feel here at the helm 😅😅
At that time, we had a very similar TV programme in Germany that also occasionally did such kind of things. The WDR Computerclub. I think the programme ran until 2002 and one of the original presenters is still active on TH-cam today.
I remember that show going out! I never tried to build the equipment but I do recall some things about it. The part nobody could find at the time was the rubber suction cup you needed to stick to your TV screen. Also I seem to recall the flashing cursor thing was transmitted over other programs on the channel because it took so long to actually broadcast anything that way.
I think your problem may be that even when a CRT television is showing a black screen, the phosphor is still illuminated to some degree. Try the reader on a copy of the show playing on an OLED tv, where black is truely black and that might work. To be honest though, I never heard of anybody being successful with it back in the day.
Also an interesting fact about Thames TV who made that show. I was present at their last but one recording ever made at their famous studios at Teddington Lock. It was the sitcom "Not Going Out" where lee proposes to Lucy.
Believe it or not I had the same trouble finding a suction cup. These days they're only transparent, which will let outside light in. The one in the video description is the best compromise.
@@RetroRecipes I can't remember what they suggested trying for the suction cup back in the day, but I do think they came back to the issue at some point.
"jet set willy smaller" lmao
Very nifty project!
Thank you for sharing!
That photo-diode looks like its an infra-red job, it won't work at all well with a TV screen.
Visible light ones have clear lenses, infrared ones appear black to the eye, but are actually transparent to infrared light. The ones you have are probably intended to receive IR remote control signals etc.
6:42 Don't forget that PAL CRTs frame rate would have been 50fps when originally broadcast so you would be missing a few frames or the frames might be merge together in the low quality transfer you have.
True. Even if the video file is 50 fps, deinterlacing of the source plus the setup with the computer doing playback might cause issues. The best bet for it to work is playing the show in its original 576i50 straight into the monitor.
See pinned comment 👍🕹
This video reminded me of one of the most coolest tech that I used to own as a kid. It was a ‘Wheel of Fortune’ game. It was just a simple blue box with a QWERTY keyboard and a multi line LCD display. The amazing part of this device is that it literally allows you to play along with real contestants on the actual gameshow when it airs at night.
When you tune in to the nightly Wheel Of Fortune program and Pat Sajak has a puzzle in play, you’d point the toy at the TV screen and through the very analog scanlines in your CRT, the device would ‘download’ the puzzle, and at home, you’d be playing the exact puzzle that the contestants are playing through this device!
The device wasn’t completely reliant on the TV show; it had hundreds of built in puzzles you can solve when you play with the device ‘offline’
As a kid, that absolutely astounded me.
@@3ffrige wow....Ingenuity
Moving away from the actual subject for a moment. I'm quietly chuckling at the particular moment from CP2077 that you threw in.
Jet set willy! Ahem.. Moving right along.