MIDI controlled light bulb fixture using vintage style "edison" light bulbs.
The control box serves a few purposes, but mainly allows you to change modes:
- CLASSIC - MIDI notes are mapped to bulbs Cn-Bn mapped to bulbs 1-12, intensity of bulbs is fully on, sustain pedal holds notes of same time, clears all bulbs when released.
- VELOCITY - same as Classic, but intensity of bulb is controlled by the velocity of the note played.
- SCROLLING (shown in video) - in this mode, bulbs are lit up sequentially as more notes are played, with intensity of the bulb based on velocity of the note. Releasing the sustain pedal clears the bulbs.
- AUTOMATIC - Slow moving algorithm that creates a changing visual display in random patterns.
I divided the steps up into three parts :
- Hardware (1-3) - Light bulbs, sockets, mounting, etc.
- Electronics (4-7) - Explanation of circuitry, how to control light bulb intensity (dimming), midi communication
- Software (8-10) - Details into the Arduino firmware, using timers, interrupts and PWM to control the light bulb intensity.
Step 1: Hardware : Light Bulbs and Sockets
I chose to use the smaller socket light bulbs (candelabra base, E12 socket) mostly because I had a bunch laying around from another project. However, the smaller base is less of an eye sore in my opinion, and typically is much cheaper than the standard E-26 base light bulb socket (standard light bulb size). I was able to get these sockets on ebay for about 50 cents a piece, which is a lot cheaper than paying $3-4 for a standard light bulb socket.
When soldering the wires to the sockets, you'll notice the solder joint is covered by shrink tubing. That's very important, especially for the live side of the wire so that you can't accidentally shock yourself when it's plugged in. The shrink tubing also provides some mechanical support so that not all of the weight is on the solder joint. I'll talk about it more in the electrical section, but it's very important that the neutral wires are soldered to the outer shell of the socket, not the other way around. This makes it significantly safer for people to be around, in the case that you used exposed metal sockets like I have. The safest solution would be to use insulated sockets, although they will likely be bulkier and more expensive.
The light bulbs come from 1000bulbs.com , although, edison bulbs can be obtained other places as well, including home depot. The important thing is to get a bulb with low wattage. You don't want 12 60 watt bulbs lighting up in your face, even at 25 watts, it can be a little strong sometimes. In addition, the lower wattage makes the electronics and wiring easier because of the lower current requirement.