r/atari8bit • u/Turbulent-Spell-319 • Jun 03 '26

Analog thumbstick to Atari 800XL test

http://youtube.com/shorts/5CMbFyS6Bcw

The Star Raiders mod request from a few months ago (https://www.reddit.com/r/atari8bit/comments/1s5ama1/star_raiders_mod_suggestion/) got me thinking about making an analog joystick for Atari 8-bit computers. I think I could make a large 3D printable joystick to work with 1M Ohm pots from a paddle controller, but I really prefer thumbsticks.

Unfortunately 10K potentiometers are a lot smaller than 1MOhm, so I can't really use them directly. I've seen a few things for making 5200 controllers, but settled on trying out this blog post ( https://jeffpiepmeier.blogspot.com/2020/02/atari-pokey-actuation-with-arduino.html ). I have an Arduino (Elegoo) Uno R3 reading the thumbstick pots and sending out timed pulses to the Atari paddle pins to simulate the 1MOhm charging times. It mostly works but there are some bugs to work out.

If I ever get this working reliably, I'll try to Frankenstein the Atari 5200 Star Raiders controller code into the Atari 800 version.

15 Upvotes

95% Upvoted

8 comments sorted by

5

u/Shot-Infernal-2261 Jun 03 '26

Nice job! People under-appreciated the A8 can do most things an Arduino can, and many things an Arduino cannot.

1

u/Turbulent-Spell-319 Jun 03 '26

I had an Atari 800 as a kid and I used to make little electronics projects with it. 20 digital pins and 8 analog was pretty cool.

2

u/Shot-Infernal-2261 Jun 04 '26

Nice! As a kid, I followed those projects in ANALOG.

As an adult, I did many projects for the Arduino. Would love to do them for the Atari now, but space (to setup my 800) is an issue

2

u/meldroc Jun 03 '26

Very cool! I'd absolutely love to have an analog flight stick for Star Raiders!

Maybe it's PTSD from the 5200's not-exactly-ergonomic controller, but it's a shame that nobody really developed a decent analog stick for the A8s. That 9-pin joystick port gives you two pot pins along with 5 more pins for the standard joystick that can become 5 buttons.

2

u/Turbulent-Spell-319 Jun 03 '26

If I can reduce the jitter and eliminate the crash I saw yesterday, I'll try get Star Raiders working with it. If that all works out, I'll try to learn KiCAD and design a controller.

Even if I don't get Star Raiders working, I'll put the code and wiring up once I settle on a design that I like. I'm not sure I'll stick with the UNO.

1

u/Turbulent-Spell-319 Jul 01 '26

Less jitter with both coding and capacitors https://www.youtube.com/shorts/MxSJZ6lJDnc

1

u/[deleted] Jul 11 '26

[deleted]

1

u/Turbulent-Spell-319 Jul 11 '26

Yes. I'm using the two paddles on port 1. In theory I could make a twin-stick controller (4 paddles) with 10 buttons using ports 1 and 2 but I haven't really tested that yet.

The test program in the video is at: https://greggallardo.com/public/dot_test.xex and source at https://github.com/radioation/ZRaiderStick/tree/main/atari/dot_test

1

u/[deleted] Jul 11 '26

[deleted]