2021-12-08 (W) EWC_Panel MIDI polarity detector

I struggled with making sure my MIDI ports were wired correctly to the point that I planned to add an activity light to each panel. Indicators are still not a bad idea, but I will make a portable MIDI tester for now. Since MIDI transmitters send enough power to turn on an LED, I designed a socket with a couple of holes for two lights. One will be green and the other red, so a broadcasting device will show a flickering green light when appropriately connected and red if the wires are reversed. I adapted the model from my MIDI↔TRS experiment since it worked well last time. I wanted to install a single three-color LED from my stock, but it wasn't built for polarity detection, so I opted for two single-color lights instead. I could have added a couple of diodes to make it work, but it wasn't worth the trouble.
Underside of MIDI testing module

I added 220Ω resistors to a couple of LEDs while the print cured. Since I was copying an earlier MIDI adapter, I matched the component leads with the length of the plastic case. Of course, I made them a bit longer to seat the lights before sealing up the two halves. I put heat-shrink tubing on all the wires and right over the resistors, but it was clear, so the color code was still visible. I attached my wires to the MIDI port, triple-checking the polarity, and put a tube over each of those pins. It assembled well, and I tested the port on my timing panel, which I already knew was good. The next time I wire a MIDI port, I'll connect the leads backward and confirm that the red LED works.
This known-good port tested green

The rest of the posts for this project have been arranged by date.
First time here?

Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Completed projects from year 7
Completed projects from year 8

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