Great Hierophant Posted May 14, 2016 Share Posted May 14, 2016 Has anyone ever made a digital joystick for an Apple II? Apple II joysticks work on the same principle as IBM PC joysticks except they use 150KOhm linear potentiometers instead of 100KOhm linear potiometers. A Gravis Gamepad for the PC converts the directionals of a Gamepad into resistance values at the low, midpoint and high end of the resistance range. I would suggest you could get a Gravis to work in an Apple II by changing the resistor packs from 47KOhm to 75KOhm and wiring in a 9-pin cable. While not perfect for every game, there is a huge number of games for the Apple II that rely on simple "stick pushed/stick not pushed" controls. Has anyone ever tried doing something like this? Quote Link to comment Share on other sites More sharing options...
cybernesto Posted May 14, 2016 Share Posted May 14, 2016 I have. I built an adapter to use Atari style joysticks with the Apple II and it works great. Even though I have read this story about the 150k ohm necessary to cover the whole range, my Apple //c and other Apple IIe I tested required only 100k to reach 255. https://123d.circuits.io/circuits/438737-apple-ii-digital-joystick-adapter There are some other projects around with the same purpose but you won't find any as simple and with as few components as mine. The diagram only shows how to connect one button, which is what Atari joysticks have. But you could easily add a second one to use a Gravis or a Master System game pad. 2 Quote Link to comment Share on other sites More sharing options...
cybernesto Posted May 14, 2016 Share Posted May 14, 2016 Check this other project out to compare the complexity http://www.atariarchives.org/ccc/chapter9.php 1 Quote Link to comment Share on other sites More sharing options...
cybernesto Posted May 14, 2016 Share Posted May 14, 2016 And another one https://groups.google.com/forum/#!searchin/comp.sys.apple2/atari$20joystick/comp.sys.apple2/JqoLX5ijCMc/G5hbRUvrR6YJ 1 Quote Link to comment Share on other sites More sharing options...
Great Hierophant Posted May 14, 2016 Author Share Posted May 14, 2016 I have. I built an adapter to use Atari style joysticks with the Apple II and it works great. Even though I have read this story about the 150k ohm necessary to cover the whole range, my Apple //c and other Apple IIe I tested required only 100k to reach 255. https://123d.circuits.io/circuits/438737-apple-ii-digital-joystick-adapter There are some other projects around with the same purpose but you won't find any as simple and with as few components as mine. The diagram only shows how to connect one button, which is what Atari joysticks have. But you could easily add a second one to use a Gravis or a Master System game pad. If your 100KOhm pots did the trick, a straight DA-15 to DE-9 adapter with the appropriate wiring may work sufficiently with an unmodified Gravis Gamepad. Quote Link to comment Share on other sites More sharing options...
cybernesto Posted May 14, 2016 Share Posted May 14, 2016 You'll need the circuit anyway, but yeah, with the proper wiring it would work with the Gravis Gamepad. Quote Link to comment Share on other sites More sharing options...
Great Hierophant Posted May 14, 2016 Author Share Posted May 14, 2016 The Gravis implements a version of this circuit : https://123d.circuits.io/circuits/438737-apple-ii-digital-joystick-adapter, so it may be worth trying "straight through" At worst the values may be off. Quote Link to comment Share on other sites More sharing options...
cybernesto Posted May 14, 2016 Share Posted May 14, 2016 Got it. Ok, I don't know the details about the Gravis but probably you will still need to invert the button levels. See this circuit instead http://apple2.org.za/gswv/a2zine/faqs/R030PCA2RF.GIF Quote Link to comment Share on other sites More sharing options...
Osgeld Posted May 14, 2016 Share Posted May 14, 2016 I have wired a atari stick to my apple 2 and it works fine for games with digital type inputs to get around the 100 vs 150K pot issue all you have to do is add some capacitance tween the center pin of the pot and ground, This effectively sets the new capacitance in parallel with the one inside the computer on that axis, that changes the R-C timing ratio of the 555 timer responsible for that axis to find the capacitance you need to use: ((original_potentiometer_value * internal_timing_capacitor) / new_potentiometer_value) – internal_timing_capacitor using this formula you can use joysticks of any resistance,or in this case we know the original is 150k the new is 100k and the internal capacitor of the II is 22nF sooooo ((150,000 * 0.022) / 100,000) - 0.022 = 11nf 10 is close enough and a extremely common value (cap code 103) by the time you account for tolerance it should be just about bang on The more you know (its about the 3rd time posting this book on this site, eventually everyone will know lol) and yes this will work on other computers that use 555 timer based joystick interfaces like the IBM PC if you want to wire up some 10k thumbsticks out of a old playstation controller or whatnot 3 Quote Link to comment Share on other sites More sharing options...
MarkO Posted May 16, 2016 Share Posted May 16, 2016 < SNIP > Apple II joysticks work on the same principle as IBM PC joysticks except they use 150KOhm linear potentiometers instead of 100KOhm linear potiometers. >> BIG SNIP >> Don't You Mean, "IBM PC joysticks work on the same principle as the Apple II joysticks, except they use 100KOhm linear potentiometers instead of 150KOhm linear potentiometers"?? I mean the Apple ][ was developed before the IBM PC.... MarkO Quote Link to comment Share on other sites More sharing options...
Great Hierophant Posted May 16, 2016 Author Share Posted May 16, 2016 (edited) Don't You Mean, "IBM PC joysticks work on the same principle as the Apple II joysticks, except they use 100KOhm linear potentiometers instead of 150KOhm linear potentiometers"?? I mean the Apple ][ was developed before the IBM PC.... MarkO That is an historical improvement, but even better is : "IBM PC joysticks work on the same principle as the Apple II joysticks, except IBM PC-compatible joysticks use 100KOhm linear potentiometers instead of 150KOhm linear potentiometers used by Apple II-compatible joysticks". The extra words make it clear which type of potentiometer is used by each type of joystick. Edited May 16, 2016 by Great Hierophant 1 Quote Link to comment Share on other sites More sharing options...
Aunty Entity Posted December 12, 2018 Share Posted December 12, 2018 I have. I built an adapter to use Atari style joysticks with the Apple II and it works great. Even though I have read this story about the 150k ohm necessary to cover the whole range, my Apple //c and other Apple IIe I tested required only 100k to reach 255. https://123d.circuits.io/circuits/438737-apple-ii-digital-joystick-adapter There are some other projects around with the same purpose but you won't find any as simple and with as few components as mine. The diagram only shows how to connect one button, which is what Atari joysticks have. But you could easily add a second one to use a Gravis or a Master System game pad. Is there a current link for that? It goes nowhere now... Quote Link to comment Share on other sites More sharing options...
cybernesto Posted December 12, 2018 Share Posted December 12, 2018 Unfortunately Autodesk stopped 123circuits. I didn’t look for an alternative. If you are interested in buying one adapter send me a PM. Gesendet von iPhone mit Tapatalk Quote Link to comment Share on other sites More sharing options...
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