So I survived running a convention, and wanted to ease back into doing some retro computing stuff. One of the projects that came up as a possibility was a pair of Atari Paddle controllers. I already have paddles for the C64, but they use different variable resistors, and so are incompatible.
(As an aside, while thinking about this problem, I mentally reviewed doing the project with a digital encoder, a digital potentiometer and a Pro Mini, as I could build a universal adapter for both c64 and Atari, but decided that’s a project for another day. In the middle of contemplation I found myself waking up at 3am and finding myself thinking “I wonder if I could design a digital potentiometer? Turns out I could indeed design one.)
Anyway, I already had some nice spinner tops left over, so it was going to be a quick trip down to my local electronics shop to pick up some bits and pieces. There were some out of stock so I ended up doing some substitutions at the last minute, but here’s what I got:
- 2 x 1 MΩ Linear Potentiometer.
- 2 x Pushbutton.
- 2 x medium jiffy boxes.
- 1 x small junction box.
- 2m of 4 core wire. (I used security system wire).
- 1 x IDC DE9 female connector.
(And from the parts box)
- a 6×2 Dupont connector shell.
- a 6×1 Dupont connector shell.
- a small length of IDC cable, at least 6 strands.
- a small bit of veroboard.
- some pin header to make 6 pins.
- some pin socket to make 6×2 pins.
- 6 female Dupont crimps.
- 8 male Dupont crimps.
Originally I’d planned to terminate everything to a solder DE9 female and hide all the “gubbins” in the shell for the connector. Unfortunately they were out, this the change of plan.
I measured and drilled the jiffy boxes to make sure they’d be vaguely comfortable in hand. (I then had to revise as I wanted a push button where the box had a support, so I had to move the buttons down a bit)
I mounted the potentiometers and buttons into the box, cutting off the shaft of the potentiometer to the correct length with a hacksaw. This is easiest to do once everything is mounted.
I cut the cable into two lengths and fed it through into the jiffy box, stripped the end and soldered it onto the potentiometer and the fire button, making sure to record the colour codes of what wire was connected to what component. I made sure both matched, to make construction easier.
I the cable tied the cable from the inside of the jiffy box, and added some heatshrink to the outside (I use two layers) to anchor the cable in place. 4 screws in each box secured the base, and then I used an allen key to tighten the spinner knobs to the potentiometer shafts.
Having finished the controllers, I moved onto the rest of the design.
I crimped the IDC cable to the IDC DE9 using my desk vice. I then stripped and crimped on 6 Dupont female crimps. These were so I could easily change any wires if I mucked something up. I had used 8 strand cable left over from another project so I just trimmed the connectors I didn’t need.
Next I got the veroboard (A scrap left over from another project) and soldered in all the sockets and pins. this was a straight through arrangement with 1 pin connected to 2 sockets. It just made it easier for the two connections that needed to be doubled up. Past me would have tried something ugly like crimping two wires onto one Dupont connector, but I have learned my lesson. I will, however, need to buy a LOT more female Dupont crimps in the not too distant future.
Next up was crimping on the Dupont male crimps to the wires from the controllers. At this point I put the female crimps in the 6 x 1 shell and attached it to the vero by the pin headers. I then worked out which wires needed to go to which connection and built up the 6 x 2 shell and male Dupont crimps until I had a suitable connector to drop in the socket at the other end of the strip of vero.
I took time at this point to make sure all the pins went to the correct place on the DE9. I have been foiled in the past by the order the pins come out on IDC connectors so I took it slowly, knowing that if I had to, I could always rearrange the Dupont connector order. They’re quite mechanically strong, but you can pop them out with the aid of a pin.
Once everything was checked I tested on the actual Atari 800xl itself, and it worked fine! After that it was a simple matter of closing up the junction box over the 3 cables and sealing it with a cable tie. A final change was to gently bend back the “ears” on the DE9 to make a better fit.
It took about 3½ hours all told, and that was not pushing myself at all.