The Handmaiden v2 Prototype — Old Man Modular

Behold! The Handmaiden v2, a control surface for my modular synthesizer driven by gamepad thumbsticks and arcade buttons.

Each joystick produces a pair of CV outputs of ~4-8V +/- along the X and Y axes. The range and polarity is customizable with the knob and switch on the bottom right. The arcade buttons allow for momentary gates and each have a corresponding toggle switch. Springs on most of the joysticks have been removed such that they don't spring back to 0 when not being touched.

The enclosure is made of canary wood and pau rosa; the palm rest is made of walnut, carved specifically for my hand—which becomes pretty clear when my wife tested it out and could scarcely get the tips of her fingers on the joysticks. If this were destined to become a viable product, this palm rest would have to be more easily replaceable (or ideally hot-swappable.)

And now, schematics! It’s in fact a very simple circuit. At the core is a fairly simple pair of power rails, positive and negative produced by a dual potentiometer that divides the +/-12V input into ~+/-4-8V and then is buffered by the TL072. When SW1 is in the ON position, the negative rail goes to ground.

These rails are connected to each potentiometer on the thumbsticks and the divided voltage is buffered—once for the output voltage and again for the LEDs. The buttons and toggles output a buffered signal from the positive rail when on. It’s all fairly straightforward.

I’ll be experimenting with this in the coming weeks and seeing how well it works. The goal, of course is the increase the number of control voltages that can be independently controlled with one hand—and with hopefully some level of comfort.