Arduino project finished…
The missing components turned up so I spent a day building the MIDI interface board. Figuring out where to place the various connectors and components on the prototyping board so that the connectors were not blocked by the sides of the box it would all live in was far harder than writing the code or designing the circuit. Once I had it all hooked up I tried it and…. nothing! Well, the switches worked as did the LEDs but I was not getting a MIDI signal out of the box, or if I was the other end was not detecting it. When I looked at the circuit for the commercial MIDI interface board I had it was a lot simpler than my over engineered effort so after some hesitation I ripped out the output circuit from my board and replaced it with a much simpler version based on the commercial units circuit (basically one wire and a couple of resistors, no transistors). Swapped over the output cables to account for the circuit changes and tried it…. nothing again!
Now had been very careful about hooking up the output wires to the MIDI connector the right way around. Seems I was not careful enough! On a whim I swapped them and of course it worked. It was probably OK the first time, just the had the wires the wrong way round but at least it works now.
This is what the inside of the project looks like:
As you can see pretty cramped. The board you can see is the MIDI interface board I made. The Arduino is underneath that screwed to a piece of board that is then glues to the case to hold it in place and insulate it from the metal box.
I always think that it is a shame to hide all the electronics as so much effort goes into creating it. In some ways it’s like programming, you can put a lot of effort into making some code as elegant as possible but in the end, all people care about is ‘does it work’.
So with that in mind, this is what the completed project looks like:
The power switch is on the other side of the box but that’s it. The left button controls the bypass on the effects unit and the right button switches between two patches. The LEDs just indicate the current setting that is selected for each switch. All pretty simple.
Time to go play!