4 ms·

Title doesn't do any justice, it's an all-discrete circuit made from diodes, transistors and such. They are soldered not on a PCB but mostly free hanging in air

Title doesn't do any justice, it's an all-discrete circuit made from diodes, transistors and such. They are soldered not on a PCB but mostly free hanging in air above a copper ground plate. One wrong move and "bazoing" sparkles. The guy didn't draw a schematic beforehand either. He mostly made it up as he went. Amazing. http://www.eevblog.com/forum/projects/oscilloscope-pong-for-1-or-2-players/?action=dlattach;attach=298785;image http://www.eevblog.com/forum/projects/oscilloscope-pong-for-...

posterboy 10y ago
I just thought, if the idea isn't to reflect waves in a transmission line I'm going to be very disappointed. Now I'll have to leave the idea here: The speed of transmission in long connections is measurable. The electromagnetic pulse travels with lightspeed and the big impedance mismatch at the end of an open line will reflect the most of the pulse. The proportion of the length to the time of transmission is almost 1/c in conductors, approximately 1 meter per 3 nano seconds. Using really long lines and switches on two sides of a closed loop, a game of reaction could be created. Kilometer long coils might not seem viable, and I don't know enough about wireless transmission to paint a nice picture, but induction introduced by coils of wire would delay a wave packet proportional to a 4th of the frequency of the wave. Edit: Bonus points for attaching a buzzing speaker each to either end :)
- VLM 10y ago
  Its a XY oscope so the highest freq signal required in the schematic appears to be 1200 Hz look at his clock gen system around page 17. In the "good ole days" you'd use IC opamps instead of transistor ckts to directly generate NTSC video signals at an analog level. There are a zillion google able links here is one: http://www.electronixandmore.com/projects/pong/index.html http://www.electronixandmore.com/projects/pong/index.html Or an example of digital logic driving a scope http://www.electronixandmore.com/projects/scopepong/index.html http://www.electronixandmore.com/projects/scopepong/index.ht... In the 80s or early 90s it was a "thing" in Z80 programming class to drive two DAC with a Z80 running some assembly language you wrote yourself to display a vector cube. Then you demonstrated your ability or lack thereof WRT trig and made the cube rotate. That took about two lab periods. There were a couple alternatives for that lab and I did a sampler where I had an A/D sample a bit less than 64K of sound at 8Ksamples/sec when a button is pressed and then it output the sample repeatedly. It was kinda fun.
usernam 10y ago
Any idea on what material the thick support wires mounted on the PCB are made of?
- pjc50 10y ago
  Tinned copper like everything else is what I'd expect.
VLM 10y ago
"mostly free hanging in air above a copper ground plate" It is impressive work, both for people inside and outside the industry. I've built a lot of RF stuff that way, his technique is "normal". What impresses me about the quality of his work is there's no solder or flux splashes on the board and none of the wires have been burned by the iron and the board isn't tarnished like an old copper penny from all the handling. Also there's no visible reworking. A lot of people buy non-inductive carbon comp many meg value resistors for use as standoffs which I didn't see in the pixs I saw. Most relatively low impedance ckts laugh at being shorted to ground by 8.2 megs yet it can be physically useful to anchor connections. Another option I've done and seen others do is take a piece of PCB and chop it into squares and stick the squares on the groundplane with glue or solder. I've had unfortunate incidents with the "hacksaw a grid of isolated squares" where the hacksaw didn't isolate the squares so I haven't done that since the 80s, but others have better luck. I've had extremely mixed results making microstripline using a shear and soldering the strips into place. You can buy pre-etched boards to support ground plane construction, including little boards when you need some SMD. I've done the "flip the chip over, super glue, and solder wire wrap wires to the leads" but its not fun. I made a complete 80M ham radio receiver back in the 80s using the ARRL Hayward "radio amateur solid state design" or something like that, the title was all generic words you can't google for, using that construction technique. The brown book with the 70s era power RF transistor on the front cover (back in the bad old days when like 100 watt device cost like half a car payment and blew up if you looked at it wrong and was made of beryllium oxide heat sink and came with a toxic waste shipment bag for when you disposed of it). Anyway it looked like a war relic by the time I was done. I think I built at least two VFOs and three mixers by the time I was done (different designs, troubleshooting to get lower drift, etc) and things gradually got trashed as I modified endlessly. I'm not sure every stage was simultaneously 100% perfect at any time, but at one time or another every stage at least momentarily worked. The truly skilled make things look easy that are actually pretty well impossible, which makes the article very impressive.
- blacksmythe 10y ago
  >> I've done the "flip the chip over, super glue, and solder wire wrap wires to the leads" but its not fun. Depends on your idea of fun, but this is a pretty standard way of breadboarding analog/RF circuits. (not used much as PC board fab has gotten so fast and cheap) I have done it many times, and I think it is fun :)

posterboy 10y ago

I just thought, if the idea isn't to reflect waves in a transmission line I'm going to be very disappointed. Now I'll have to leave the idea here: The speed of transmission in long connections is measurable. The electromagnetic pulse travels with lightspeed and the big impedance mismatch at the end of an open line will reflect the most of the pulse. The proportion of the length to the time of transmission is almost 1/c in conductors, approximately 1 meter per 3 nano seconds. Using really long lines and switches on two sides of a closed loop, a game of reaction could be created. Kilometer long coils might not seem viable, and I don't know enough about wireless transmission to paint a nice picture, but induction introduced by coils of wire would delay a wave packet proportional to a 4th of the frequency of the wave. Edit: Bonus points for attaching a buzzing speaker each to either end :)

VLM 10y ago
Its a XY oscope so the highest freq signal required in the schematic appears to be 1200 Hz look at his clock gen system around page 17. In the "good ole days" you'd use IC opamps instead of transistor ckts to directly generate NTSC video signals at an analog level. There are a zillion google able links here is one: http://www.electronixandmore.com/projects/pong/index.html http://www.electronixandmore.com/projects/pong/index.html Or an example of digital logic driving a scope http://www.electronixandmore.com/projects/scopepong/index.html http://www.electronixandmore.com/projects/scopepong/index.ht... In the 80s or early 90s it was a "thing" in Z80 programming class to drive two DAC with a Z80 running some assembly language you wrote yourself to display a vector cube. Then you demonstrated your ability or lack thereof WRT trig and made the cube rotate. That took about two lab periods. There were a couple alternatives for that lab and I did a sampler where I had an A/D sample a bit less than 64K of sound at 8Ksamples/sec when a button is pressed and then it output the sample repeatedly. It was kinda fun.

usernam 10y ago

Any idea on what material the thick support wires mounted on the PCB are made of?

pjc50 10y ago
Tinned copper like everything else is what I'd expect.

VLM 10y ago

"mostly free hanging in air above a copper ground plate" It is impressive work, both for people inside and outside the industry. I've built a lot of RF stuff that way, his technique is "normal". What impresses me about the quality of his work is there's no solder or flux splashes on the board and none of the wires have been burned by the iron and the board isn't tarnished like an old copper penny from all the handling. Also there's no visible reworking. A lot of people buy non-inductive carbon comp many meg value resistors for use as standoffs which I didn't see in the pixs I saw. Most relatively low impedance ckts laugh at being shorted to ground by 8.2 megs yet it can be physically useful to anchor connections. Another option I've done and seen others do is take a piece of PCB and chop it into squares and stick the squares on the groundplane with glue or solder. I've had unfortunate incidents with the "hacksaw a grid of isolated squares" where the hacksaw didn't isolate the squares so I haven't done that since the 80s, but others have better luck. I've had extremely mixed results making microstripline using a shear and soldering the strips into place. You can buy pre-etched boards to support ground plane construction, including little boards when you need some SMD. I've done the "flip the chip over, super glue, and solder wire wrap wires to the leads" but its not fun. I made a complete 80M ham radio receiver back in the 80s using the ARRL Hayward "radio amateur solid state design" or something like that, the title was all generic words you can't google for, using that construction technique. The brown book with the 70s era power RF transistor on the front cover (back in the bad old days when like 100 watt device cost like half a car payment and blew up if you looked at it wrong and was made of beryllium oxide heat sink and came with a toxic waste shipment bag for when you disposed of it). Anyway it looked like a war relic by the time I was done. I think I built at least two VFOs and three mixers by the time I was done (different designs, troubleshooting to get lower drift, etc) and things gradually got trashed as I modified endlessly. I'm not sure every stage was simultaneously 100% perfect at any time, but at one time or another every stage at least momentarily worked. The truly skilled make things look easy that are actually pretty well impossible, which makes the article very impressive.

blacksmythe 10y ago
>> I've done the "flip the chip over, super glue, and solder wire wrap wires to the leads" but its not fun. Depends on your idea of fun, but this is a pretty standard way of breadboarding analog/RF circuits. (not used much as PC board fab has gotten so fast and cheap) I have done it many times, and I think it is fun :)