cbelcher Posted June 21, 2022 Share Posted June 21, 2022 Searching around non-English language Atari literature, I found a project from around 1990 that sparked some interest. It is a resistance / capacitance meter that runs on the 8bits that interfaces through the joystick port and is based on a 555 timer. I found it here: From AK BRNO Hardwareove doplnky – Mikrocentrum BRNO http://atari8.cz/calp/data/br_man_hw/ Did some Google translating, looked at the schematic and the original pcb and recreated them. Then back to the old days of typing in software - and trying to find errors in the poor text scan. How does it work? Not well... But it is fun. Definitely needs calibration - it is a y=mx+b equation for each the resistance and capacitance - detailed in the documentation. It will never replace your cheapest multimeter, but it does illustrate some interesting hardware hacking. I made a Word document with my poor translation and the original materials, attached. Also there are pictures of the program and my finished PCB and an .ATR below. Atari R-C meter.docx Enjoy! RCMeter.atr 5 2 Quote Link to comment Share on other sites More sharing options...
machf Posted June 21, 2022 Share Posted June 21, 2022 Definitely sounds interesting... I'll take a look at it and try to figure out how it's supposed to work. That should help wih the documentation. Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted June 21, 2022 Share Posted June 21, 2022 @Gunstar One for you Matt? Quote Link to comment Share on other sites More sharing options...
E474 Posted June 22, 2022 Share Posted June 22, 2022 Hi @cbelcher, Are you going to share the PCB/Kicad/source files too (I appreciate it's a simple circuit)? Quote Link to comment Share on other sites More sharing options...
machf Posted June 22, 2022 Share Posted June 22, 2022 (edited) 22 hours ago, machf said: Definitely sounds interesting... I'll take a look at it and try to figure out how it's supposed to work. That should help wih the documentation. Well, aside from "8x8 cm" (just to prevent any confusion with the measurement units), I don't think there's anything wrong with the translated documentation, at least after a quick look last night. Just got me thinking if it would be feasible to write code to graph the capacitor charge/discharge curve... Edited June 22, 2022 by machf Quote Link to comment Share on other sites More sharing options...
cbelcher Posted June 22, 2022 Author Share Posted June 22, 2022 I did look at the timing data on the Atari side for known resistors and capacitors and played with some best fit curves and the linear equations did quite well over the range. I do have a few boards left over if people are interested. Quote Link to comment Share on other sites More sharing options...
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