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BigO

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Posts posted by BigO

  2. Posted

    I've made a cable, but I had an actual Kid Vid to use it on so I never had to do a deep dive into the "how does it work?" issue.

    Looking at the cable schematic, it appears to be using pin 8 Ground for one of the pins.

    That could mean several things:

    1. The Atari is switching +5V on/off with respect to ground by leaving that second pin in output mode and alternating between HI and LO.
    2. The IO pin is being switched between input and output mode. If pulled LO when in output mode, that would apply 0V to both pins, possibly looking like a closed switch. When in input mode, it would be high impedance looking like an open switch.
    3. Something else that I'm not clever enough to reason out.

    I would test the output of the Atari by measuring the IO pin against both ground (controller pin 8 ) and +5V (pin 7) when the tape is supposed to be active and inactive. If you get no voltage from the IO pin with respect to pin 8 and no voltage with respect to pin 7 then you know that the IO pin is set to input mode, thus providing a high impedance (like an open switch). Otherwise, if the IO pin is in output mode, you'll get a voltage against one of those pins and you'll know it's just switching between HI and LO output states.

     

    It seems likely that whatever scheme was employed could be adapted with a transistor or something to drive a different type of tape recorder. If you can figure out what exactly the Atari is doing, you or somebody else should be able to use those signals to ultimately drive a simple SPST dry contact relay (using appropriate flyback diode and/or other means of isolation and protection). With that achieved, you would be able to drive nearly any of these tape decks with the "remote" switch no matter what scheme it employs to detect the switch condition.

    Have you measured for voltage across an open mechanical switch that's "remote" controlling your tape recorder? Maybe it is putting out a voltage and interrupting or passing it through to control the tape motor. This would be the other half of the equation needed to understand why it's not working when driven by the Atari. Have you looked at the internals of the jack that it plugs into? Plugging something into the jack may mechanically break the connection to the motor power. Or, it may be providing ground or something to a more sophisticated circuit.

    I gave away the last tape deck I had or I'd now be compelled to pop it open and figure out exactly how the remote function worked. :)

  3. Posted

    Once I saw it, I realized it must be a way around technical constraints and the Venetian Blinds effect did come to mind but I never really understood what it meant nor did I realize it was a "back in the day" thing.

    Now I know. And, yeah, I'll never be able to un-notice either. Probably will never be able to wrap the score again due to the distraction of the score display.

  5. Posted

    I suppose it would depend on the jitter being observed. I can see how ripple that's not in sync with the sampling frequency could cause the paddle input to vary with no actual change in resistance, but I wouldn't expect it to amount to much.

     

    I haven't noticed that happening on the 2600. If you're seeing that on the 2600, I don't see much harm on trying it. I guess if there's substantial resistance between the power supply and the chip somewhere this could cause the TIA to power up too slowly, but that's a stretch.

     

    But, jitter on the 2600 is widely known to be caused by dirty or otherwise malfunctioning pots. I haven't seen anybody claim that addressing the pots didn't fix the jitter problem.

    • Like 1

  6. Posted

    With the availability these days of cheap microcontrollers, the hardware cost of circuitry to decode and translate the quadrature signals wouldn't be my biggest concern.

     

    A sub-five-dollar Arduino Nano can handle decoding and translating two quadrature signal streams with plenty of resources to spare. Though, there would be the additional one-time cost of developing the software and per-unit cost of programming the devices might be a meaningful cost factor for production.

     

    I think the mechanical portion of encoding of ball motion would be the hurdle that I couldn't affordably get over.

  7. Posted

    About the same. I wasn't a rabid gamer then and now I tend to spend more time building controllers to play games with than actually playing games with them.

    I keep telling myself when I finish my current multi-function controller project that I'll actually use it...

  9. Posted

    The graphics werent complicated, but getting the colors and pyhsics correct might be an issue. https://m.youtube.com/watch?v=aqcDFAphThY

    One of the playfield variants has about 10 blocks on the same vertical line. Each of those blocks can be an independent color, so you would have to mix using P0, P1, and background so that you could display each of the blocks as the correct color, and I am not even sure if there is enough time to change the color colors. (If there are only 3 colors, it might be possible...)http://atariage.com/forums/topic/170018-multiple-colors-per-scanline/

    The other hard part would be getting the physics correct. The game was made on a dedicated microprocessor and I dont think the source code exists.

    I'm not sure it's directly applicable, but I recall the homebrew Chunkout displaying at least 8 different colored blocks one one line.

  10. Posted · Edited by BigO

    Some of those pictures look typical of dirty cartridge and/or port contacts. I'd try cleaning them because it could be that simple.

     

    You should be able to search out a number of threads covering that subject.

     

    On the other hand, at least one doesn't quite look like I'd expect. The last one looks like it's rendering some elements correctly but not others. That could be a deeper problem.

  13. Posted · Edited by BigO

    The PAL/NTSC compatibility of a cartridge is a property of the software game program, not the cartridge hardware.

    If you have an NTSC console, you'd need an NTSC flavored ROM to be installed on that custom cartridge.

     

    Some PAL only titles have been converted to NTSC versions so you might be lucky there. I'd recommend contacting Al via e-mail if you have concerns about what you've already ordered.

    • Like 1

  16. Posted · Edited by BigO

    Is it broken? The paddles don't move now.

     

    For play testing a homebrew paddle controller, I was looking for paddle games.

    I downloaded the latest version a apong.bin to my Harmony Cart, overwriting the version I had before.

     

    To be sure it wasn't a problem on my end, I have:

    • Tested with OEM paddles and no luck there either.
    • Downloaded the original version from the first post and the paddles work fine.
    • Downloaded the latest version several times from the recent post to assure no corruption
    • Downloaded the latest version from the first post so I don't think it's a corrupt download.

    Is it just me?

  17. Posted

    For the record, I don't dispute what Stephen Moss is saying. I wasn't engineering a final solution, just addressing the need to switch only one pin of each controller and throwing out brainstorming style tidbits.

     

    It seemed like the OP solution was possibly overly complicated which was likely to affect power requirements, but I am not a professional in the field.

     

    Good luck with the project.

  18. Posted

    For reference, I'm driving an arduino, quadrature encoder, and a digital potentiometer off of an RF connected light 6'er and don't see any impact on the video even if I plug it in while the console is already powered up.

     

    I've powered a few odd things from the 2600. The only time I've seen anything weird was when I accidentally backed USB power into the console while it was powered off. That just made the static on the screen more black.

  19. Posted · Edited by BigO

    You may be correct but I would be surprised if they were floating as any noise could result an accidental fire/movement, disrupting game play.

     

    I can see why someone might think they are floating as there are no pull up resistors shown on the schematic, but I would be surprised if the relevant input pins did not have transistors pulling them high inside the RIOT & TIA to ensure an consistent and noise immune input state when the joystick direction/fire are not actuated. This can be easily tested by just measuring the voltages on the direction of the RIOT/controller port, if they read in the 4-5V range they are pulled up internally, if not they are floating.

     

    Stephen Moss, you are correct. Undoubtedly, there are pull up resistors at play inside the console/IC's. In hindsight, my phrasing was ambiguous at best.

     

    By "All of the inputs to the 2600 are just floating", I meant the controller output pins with respect to their influence on the inputs. Better phrasing might have been "the outputs from the controller where they connect to the console inputs are just floating. They exert no influence on the inputs".

     

    The significance is that two joysticks can be connected in parallel and until actuated, both would remain completely transparent to the console inputs. In order to switch between the joysticks, one would need only to break the pin 8 ground connection to one joystick to make sure it was the other joystick being read.

  21. Posted

     

    I've read elsewhere that the pots are 0-640k, with a working range of 0-500k and the center basically landing in the middle at 250k.

    All that I've looked at are 500K. And the working range is not the full range of the pot. If you look at how the pots are actuated, you'll see why. They rotate only about 180 degrees. It's been a long time since I measured and mechanically estimated the range so I don't recall the full range.

  22. Posted · Edited by BigO

    Not fully thought out (and I'm not claiming to be a hardware guru), but here's my knee-jerk, brainstorming reaction:

     

    At a first approximation, with a standard 2600 joystick setup, there's really no signal being sent to the 2600 until you actuate the joystick or fire button. All of the inputs to the 2600 are just floating. You should be able to fully connect two idle joysticks in parallel with no ill effect. It would only be necessary to connect/disconnect the ground signal to each joystick to determine which one is being read at that instant.

     

    The unconnected ground signal to the inactive joystick would have to be something that goes to Hi-Z rather than a digital 1 for the non-selected joystick. A tri-state buffer like a '244 might take care of floating that signal. Maybe an analog mux like a '4066.

     

    Presumably, the 2600 has some means of internally pulling up the input lines, so you probably wouldn't need external pull ups. Lower parts count, probably lower power draw.

  23. Posted

    Surprised nobody in our awesome AA community has taken the opportunity to try this... but I would surely pay good $ for a new custom awesome Trak-Ball controller design to play these awesome new Trak-Ball conversions.

     

    Surely there is a buyer's market for a few hundred+ new Trak-ball controllers to play these awesome games. Plus if they were marketed in the AA store along with the games, it would be a natural. Right?

     

    Are there any techno-savvy entrepreneurs around here that have thought about this? This also seems like a great opportunity for Edladdin as well (hint hint).

    Define "good money". It wouldn't require much technical wizardry to produce a controller that would work with these games. The quickest run to daylight would be to use off-the-shelf arcade parts but, as mentioned above, they're not what most of us hobbyists would call cheap.

  24. Posted

    I was too poor to have games like that back then. Add to that the fact that I have little interest in sports. I didn't play or own one of those red LED games until the last couple of years.

     

    I played the game (soccer) for a few days then put it away. Eventually, I sold it to an AtariAge member who happened to be in town on business.

     

    This whole genre of games was just a Blip on my radar.

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