Yesterday, I went through yet another round of design review with one of my mentors. Among the many changes that were suggested, one was to add one LED indicator per analog port. After a few iterations, I settled on the following design. It’s a bit packed, but I’m starting to really like it, and it should look better in real-life than it does on this Illustrator mockup.
I have selected the Bivar 3BC-3-Y/G-F 3mm bi-color (yellow/green) LED. Because of the sheer number of ports on the faceplate (128), they can’t be aligned with the jack chassis sockets. Instead, they’re offset to the left for channels 1 through 4, and to the right for channels 5 through 8. The output strip at the bottom should help the user remember which port an LED is related to. And while I was working on the faceplate’s design, I also made sure to add an icon for the headphones port.
These LED indicators will be used to visualize the voltage levels of our 128 analog ports. By default, they will be green. But when going over a certain threshold, they will be yellow. I have yet to figure out how they will be driven. In a perfect world, a small circuit downstream of the ADS7953 should be all we need, thereby bypassing the Raspberry Pi 2, which will be plenty busy doing many other things (I’m starting to worry about that one).