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
@@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!)
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 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 🙂
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.
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!
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!
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 for all your effort, no other Retro Channel comes close, your passion shines through on every video, and the production is so slick. Seeing that pic of Sir Clive brings me right back to my childhood in the 80s...happy memories...PS I *LOVE* the fact you actually have your original desk and monitor from back in the day.....and those old Boots Cassettes :D.....retro heaven :) Thank you, Thank you, Thank you :)
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.)
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.
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!
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.
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/
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...
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.
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.
Have you ever considered voiceover work?!? Seriously your voice and tone is just perfect for TV documentaries or the likes of how it's made etc. I feel like you are probably a well known narrator that I'm actually unaware of, but if not... Look into it!
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.
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.
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!
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...
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.
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!
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.
Would be interesting to compare the audio spectrum of the code from the compressed video to a recreation based on your manual re-typing of it; and maybe see if there is any hints of how to recover the missing part from artifacts in the compressed video....
I've managed to extract the data (i.e. the receiver program also printed in the magazine) from that quite badly mangled audio track. Not an entirely trivial process ... 😜
@@tiagotiagot There were dodgy pulses scattered all over that audio transmission. The printed version of the program included a few ML instructions less than the audio version. This may be at least a step in the right direction ...
I've disassembled the tuning and receiver programs for C64. Strangely, the receiver program looks incomplete. Here's how it basically works: HW: The multivibrator is used to lengthen the pulses read by the phototransistor in order to bridge the gap between TV frames. The tuning procedure tells you to adjust the timing of the circuit such that the lengthening of the pulses is *just* enough so the user port signal (PB7) never goes to LOW if a bright square is displayed under the sensor. Tuning program: It displays a bright square and then just checks if it ever reads PB7 as LOW. If so, it puts an asterisk '*' between the arrows. (You can clear the asterisk by pressing a key.) If the asterisk does no longer show up, it means PB7 is reading HIGH each time it is sampled. Receiver program: It first waits for a keypress. Then it waits for the bright square to disappear [
Wonderful feedback thanks. We actually have a thread discussing this. Would you like to glance at that then paste this info there? A couple of people have already rewritten the receive program there, but still no luck (we think due to the 50fps vs 25fps footage). But yours is perhaps the most thorough disassembly and I'm sure you could help fill some gaps in the info there. www.lemon64.com/forum/viewtopic.php?p=1027686 🙏
@@RetroRecipes Unfortunately I cannot find how to register on lemon64. I have put my notes on github. Will put the link in a separate comment because TH-cam seems to eat comments containing links. Github repo name is edwinst/c64_light_fantastic_reverse_engineering.
@@EdwinSteiner Ah they had a bad hack recently so may have temp stopped new registrations. Just guessing. Thanks again for sharing. I'll post on your behalf and see if anything interesting comes back.
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.
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!
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.
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.
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 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.
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,,,(
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.
This was cool and i sort of recall this show as well ...... yeah am getting old 🤣😂. Looking forward to the next part as i so so so want to know what it was now so until then keep up the great work. As always have a great weekend and you all take care 🙂
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! 😱😄
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.
It'll be interesting to see if sourcing the correct component will get it all to work. The thing is, going off on a tangent, with the mention of teletext, could there be an option to adapt the process used to recover teletext pages from standard VHS tapes to work with this? In effect, the flashing dot is sort of a zero dimensional barcode...
I remember this when it was broadcast in the uk. I think at the time we had no home computer, or we had just got an amstrad cpc 464. So I was disappointed that I couldn’t try it myself. Looking forward to part 2
No, channel 4 would be prosecuted for child abuse if they suggested actually soldering something instead of buying it ready made. I didn't know pcbway would assemble through-hole components though, I thought they'd only touch automated SMD assembly.
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 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 !
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.
You must’ve excelled as a typing student, Peri. I didn’t realize as I learned how to type on a Commodore late in my single-digit years (the 80s) that it is something many people resist learning to do. It was interesting trying to explain to some people about ASDF and JKL;.
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.
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.
Since you have the video file of the flashing dot, could you zoom in on that and change the brightness on the screen till it "sees" the difference between off and on.
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 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.
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
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
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!
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 👍🕹
From a computer operator way back to 1979.. WOW.
Those were the days, you bring back great times. i watched without blinking lol
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 🙂
@@joostluyten_ON2OT In 1981 werd Basicode door de Nederlandse Omroep Stichting in het radioprogramma Hobbyscoop tot leven geroepen
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.
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 👍🕹
I just want to say that I absolutely love your video editing style. Its absolutely delicious 😋
Thank you for your kind words! Means a lot 👍🕹
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!
Peri, you put so much effort into your videos. They're absolutely wonderful and top notch. Cheery-o!
Dude you're like computer Bob Ross, I'm here for it!❤❤❤❤
It's just a happy little accident 🎨👍🕹
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!
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 for all your effort, no other Retro Channel comes close, your passion shines through on every video, and the production is so slick. Seeing that pic of Sir Clive brings me right back to my childhood in the 80s...happy memories...PS I *LOVE* the fact you actually have your original desk and monitor from back in the day.....and those old Boots Cassettes :D.....retro heaven :) Thank you, Thank you, Thank you :)
Great video hope to see more electronics projects.
I just love how much fun you are clearly having making these videos. 🥰
Channel 4 was awesome in it's heyday. Miss the blocks.
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.)
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!
4:38 "This is a dog" XD
Very nifty project!
Thank you for sharing!
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 😅😅
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.
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/
Fractastic episode, kind sir! Splentabulous!
insanely great show! love your contents
Tinker tinker tinker, I love it! Looking forward to part 2.
This is such a cool episode! Can't wait for part II to see what that program actually is 🙂
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.
Ah bugger. Look forward to seeing this working. Cheers
So obscure. Loved the shrinked down part--very retro 80s.
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.
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.
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
Have you ever considered voiceover work?!? Seriously your voice and tone is just perfect for TV documentaries or the likes of how it's made etc. I feel like you are probably a well known narrator that I'm actually unaware of, but if not... Look into it!
christiansimpson.com 😅
@@RetroRecipes well there you go haha I'm late to the party but unknowingly nailed it on the job
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.
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.
Exciting stuff! Can't wait for episode 2!
Thinking of you guys. Hope the family is happy and healthy. Puppy too.
Love these sort of experiments! Thanks for doing them for us😊
the woman at 21:04 is so 80's 💞👍👍
A Saturday morning Perifractic project video. Definitely a welcomed blast from the past.
Where is my Capt Crunch?!??!
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!
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 😉
Theres hidden scene in 0:08 Microsoft Sidewinder Gamepad what i founded it Thanks to Retro Recipes. Microsoft are best since 1998-1999!
Love your patience and dedication...
I would of given up long ago.
I would have given up long ago too! 😁
3:02 this footage feels like video game footage but also real at the same time. Very neat effect.
That's Cyberpunk 2077 :)
@@RetroRecipes
Neat! I clearly have never played it.
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.
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!
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.
That recipode was really enjoyable. Awesome 👍😎
Genuinely one of the best things you've ever done.
Thank you for your kind words! Means a lot 👍🕹
Reminds me of when I made my Amstrad CPC6128 send and receive an email. Could not put it down ……..
Great stuff RR.
Your voice is so soothing 😊
Would be interesting to compare the audio spectrum of the code from the compressed video to a recreation based on your manual re-typing of it; and maybe see if there is any hints of how to recover the missing part from artifacts in the compressed video....
I've managed to extract the data (i.e. the receiver program also printed in the magazine) from that quite badly mangled audio track. Not an entirely trivial process ... 😜
@@_nc513_ How much of it was missing/corrupted?
@@tiagotiagot There were dodgy pulses scattered all over that audio transmission. The printed version of the program included a few ML instructions less than the audio version. This may be at least a step in the right direction ...
I've disassembled the tuning and receiver programs for C64. Strangely, the receiver program looks incomplete. Here's how it basically works:
HW: The multivibrator is used to lengthen the pulses read by the phototransistor in order to bridge the gap between TV frames. The tuning procedure tells you to adjust the timing of the circuit such that the lengthening of the pulses is *just* enough so the user port signal (PB7) never goes to LOW if a bright square is displayed under the sensor.
Tuning program: It displays a bright square and then just checks if it ever reads PB7 as LOW. If so, it puts an asterisk '*' between the arrows. (You can clear the asterisk by pressing a key.) If the asterisk does no longer show up, it means PB7 is reading HIGH each time it is sampled.
Receiver program: It first waits for a keypress. Then it waits for the bright square to disappear [
Wonderful feedback thanks. We actually have a thread discussing this. Would you like to glance at that then paste this info there? A couple of people have already rewritten the receive program there, but still no luck (we think due to the 50fps vs 25fps footage). But yours is perhaps the most thorough disassembly and I'm sure you could help fill some gaps in the info there. www.lemon64.com/forum/viewtopic.php?p=1027686 🙏
@@RetroRecipes Unfortunately I cannot find how to register on lemon64. I have put my notes on github. Will put the link in a separate comment because TH-cam seems to eat comments containing links. Github repo name is edwinst/c64_light_fantastic_reverse_engineering.
The github repo is called "edwinst/c64_light_fantastic_reverse_engineering". I tried to post the link but it did not get through, it seems.
OK, last attempt to get this through the algorithm: My user name is "edwinst" and the repo is called "c64_light_fantastic_reverse_engineering".
@@EdwinSteiner Ah they had a bad hack recently so may have temp stopped new registrations. Just guessing. Thanks again for sharing. I'll post on your behalf and see if anything interesting comes back.
Computer programs from your TV was the stuff of dreams, please make it work!
I've heard of Duck Typing but this Puppy Typing thing seems interesting
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.
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!
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.
Wow, brings back some memories :)
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.
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.
Haha I remember typing in those programs from the old computer magazines! Great memories.
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
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,,,(
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.
What an innovative concept for a TV show.
Sure glad I saw part 2 video to realize I had not watched this one yet... Bigger project than any of us expected!
looks like it would have been easier to build a working flux capacitor 😅, this is pure dedication to retro, looking forward to part 2 Peri👍
With a working flux capacitor, he could just go back and ask them what the program did.
@@Robert08010 Great Scott!! 😂👍👍
This was cool and i sort of recall this show as well ...... yeah am getting old 🤣😂. Looking forward to the next part as i so so so want to know what it was now so until then keep up the great work. As always have a great weekend and you all take care 🙂
We're all getting old along with you! 🙏
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! 😱😄
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!
It'll be interesting to see if sourcing the correct component will get it all to work. The thing is, going off on a tangent, with the mention of teletext, could there be an option to adapt the process used to recover teletext pages from standard VHS tapes to work with this? In effect, the flashing dot is sort of a zero dimensional barcode...
I remember this when it was broadcast in the uk. I think at the time we had no home computer, or we had just got an amstrad cpc 464. So I was disappointed that I couldn’t try it myself. 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.
No, channel 4 would be prosecuted for child abuse if they suggested actually soldering something instead of buying it ready made. I didn't know pcbway would assemble through-hole components though, I thought they'd only touch automated SMD assembly.
Love your creativity and attention to detail! Subbed
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 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 !
I remember ITV doing this first with their show Database and the DATABLAST
Technically isn't everything sent from the past? :D
Great video!
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.
You must’ve excelled as a typing student, Peri. I didn’t realize as I learned how to type on a Commodore late in my single-digit years (the 80s) that it is something many people resist learning to do. It was interesting trying to explain to some people about ASDF and JKL;.
Something comforting about the sound of an old disc drive work.
Even today that’s a push to do but back in the 80s 😂
The pupper yawns in the beginning 🥹🥹🥹😭😭😭
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.
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.
Since you have the video file of the flashing dot, could you zoom in on that and change the brightness on the screen till it "sees" the difference between off and on.
Funny enough that's exactly what I've done here more recently. Stay tuned!
I dig your very 1985 shoes. They look like they are from the "Future." Cheers
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
I remember building & running the software from TV. I thought it was the BBC. Yes did the cefax download as well
Thank you for this flashback video! I hit the like and am following.
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.