DEMO DIY Optical Expression Plug Controller

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EisengesisFX

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DBA's recent release of the Photo Modulator got me thinkin'. And as linked to in that thread, the company's store listing gives concrete detail on the incredibly simple wiring and components needed. I started by just taking apart a Neutrik TRS jack, soldering a GL5528 across the tip and ring, and then soldering a 47k resistor between the ring and sleeve. Boom, works. Awesome

Then I got to thinking more. For starters (and also as mentioned in the above linked thread), I had a two other LDR types on hand. Socketing would be wise. Simple enough to solder up and apply heatshrink to each.

Secondly, even on my small (~18" x ~13") board, wouldn't it be cool to have more adjustability and length versus just swiveling the plug in its jack? I had a USB LED gooseneck light I bought from Ikea over a decade ago. Some disassembly and careful (but aggressive!) removal of some metal segmentation and the heavier coil surrounding the actual wiring later went down, and I found that a spare Neutrik jack bottom-cone screwed right into the top where the LED had been. I cut the hole in the end wide enough to fit the two sockets and superglued them in place, then cut my LDR down to size.

Finally: the Neutrik size made sense if I was trying to clone the DBA Photo Modulator's size more or less outright, but since space is at a premium and, turns out, the diameter of the gooseneck absolutely fit a Squareplug S550-S, I went that route. Added a double layer of heatshrink to hopefully minimize any strain on the wiring. I wired things the same as before inside the Squareplug housing itself. Wild but not especially difficult to fit a resistor in there.

I need to test my other LDRs and tweak some of my H90/PBC6X presets to figure out when and how to implement this for texture, but I'm stoked! Cost me zero additional dollars or parts.

In the meantime, peep my test with the expression input of my Nutty Fuzz build (harmonizer is from the H90). Turns the oscillator into a shitty theremin! 😂

View attachment VID_20250922_134356_941.mp4
 
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