Antique Light Bulb Organ - MIDI/OSC Controlled

Step 9 Electronics! - Microcontroller & MIDI

I'll get into the microcontroller code in the next section, for now the important things to know are that I'm using an Atmega324p with an ft232r usb -> serial adapter, and that's about it.  I had a bunch of these boards laying around from an old project, in a small form factor that worked out perfectly.  That's my only reason for the choice.  However, this particular controller had some additional features that really added to the project.  Number one, it has two hardware UART ports, that means I can listen and send messages over USB as well as midi at the same time on separate ports.  Also, there are many more pins, so driving the 12 pins for the relays was a simple task.  In addition to the two ICs (integrated circuits) I also needed an optocoupler to listen to messages coming in from a midi cable.  There's a lot of information out there on how to hook this up, I just copied those circuits and had no problems.

The eagle files for the controller board are attached, and you can see the schematic above at the end.  Nothing really special going on there.  Something to keep in mind if you're thinking of building something like this, an arduino would be able to do all this very easily, even those mini ones, all you really need is the solid state relays, then it's only a matter of controlling 12 leds.  Also, since the board was made with a different purpose in mind, the power pin on the USB is not shorted to the power on the uC.  I did this with a jumper wire underneath the board, which isn't visible in the pictures.

The last thing that's happening from the microcontroller is the LED control of the indicator.  It's an rgb led, so there's three pins for that.