MIDI Melodies Make Moody Milieu

MIDI piano lights

In this beautiful, well-documented, cat-assisted hack, [capricorn1] adds visual dimension to his impressive piano skills by using his keyboard’s MIDI output to drive Edison bulbs.

He hung them from a rod of electrical conduit pipe and threaded the wires through it to a DB25 connector. The lights are controlled by an Arduino Mega plus a custom shield with an optocoupler to handle zero cross detection. He happened to already have a board with 12 SSRs on it from another project. All of the electronics are in a re-purposed switch box—the switches control four different modes: classic, velocity, scrolling, and automatic. You’ll see the scrolling mode in the video after the jump.

[capricorn1] used a small sampling of the Arduino MIDI Library, namely the note on/off functions and the control change function to handle his sustain pedal. He’s listed the full code for the project, which includes usage of the ipMIDI module for automation over WiFi.

If you don’t have a MIDI keyboard or any Edison bulbs, you could make a MIDI floor piano. You’re required to play both “Chopsticks” and “Heart and Soul” on it, though. Those are like the Hello, World for floor pianos.

10 thoughts on “MIDI Melodies Make Moody Milieu

  1. Video does something and then wants to download, stop, no way, end.
    There is a workspace just started in town that has a bunch of these lights hanging just the same way. They don’t animate. MatchBOX is the place it’s just desks and jacks no hacking.

  2. Summary makes it sound like he’s running 110v power to the bulbs through the DB25 connector. I don’t have the specs in front of me (and they will vary depending on composition of the plastic spacer block in the DB25), but that seems like too fine a pitch to be powering 110v incandescents through. The article indicates that they’re 25w bulbs (so depending on specific line voltage they’re between 200mA and 230mA) and that he’s running independent neutrals to each bulb, so it’s clear that he’s thought it through, but running that much juice through a DB25 still makes me a little squicky inside. Maybe it’s just me. Anyone else? Those concerns aside, it’s a very clever project!

  3. Rob, glad you’re paying attention! I was pretty concerned about that as well, I think I’ll add a page to the instructable about it… This is the DB-25 I used :
    In the spec sheet, it states it uses 26awg wire, which based on the common wire guage tables, can handle > 300mA in a bundle of wires (which is still very conservative). The connector itself is rated for 250V, so I decided I’d give it a shot, and so far, no sparks! However, you’ll notice in the pictures, there absolutely is a fuse at the entrance of the box. Anyways, thanks for checking out the project!

    1. You bet! Thanks for replying and providing the spec sheet. With those ratings you’re safely inside the limits and the fuse completes the design. I never would have guessed, but there you go and some other Bob’s your uncle. Nicely done.

      1. The pin spacing between the rows of solder cups is still too close for comfort, and the insulation on the wire you are using (both the ribbon cable and data cable) is NOT rated for line voltage. Please use proper connectors, wire with at least 150V (300V preferred) insulation, put some clear heat shrink over the sockets, and don’t run line voltage wires through drilled holes in EMT. The risk of fire or injury is too great with this project in current form.

        A better design would be to move the solid state relays up to the light bar, and only run low voltage up the control cable, and a standard extension cord for power to the lights.

        1. Hey Mike, got any references to back that up?? I know people don’t typically use DB25 cables for line voltage, but I think that has more to do with typical needs, than actual specifications. Every datasheet I have found on DB25 connectors rates them up to 300VAC, and the same goes for IDC ribbon cables. Specifically the 3M kind I’m using. I agree it would be better to run low voltage in the cable, but it would have required a lot more complexity to the mounting, or simply a larger less aesthetic design. As for fire, there’s absolutely a fuse in line with everything. I do agree about the wires running through the drilled holes, I meant to put rubber grommets there originally and sort of forgot.

          You have any reference you can share on the wiring/connectors not being rated for 120V? I can’t find any..

  4. Now to make the portable TV show the sound waveform of the output by applying an amplified audio signal to the vertical deflection coil, and the tape player control the keyboard like an 80s computer tape drive…

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