Comment by HornyDude

Throwaway time!

I built a custom smart motorized masturbator.

It borrows from 3D printer design, and has a NEMA 17 stepper motor driving a 2GT belt loop around a short length of 2020 extrusion to slide a carriage along a linear rail. The carriage has attachment points that I've put clamps on, that close around a fleshlight-style sheath. There's a brace at the business end that you put around the base of the penis and it keeps everything aligned.

All the parts are custom-designed and 3d printed.

It has an outboard control box that contains:

  - an ESP32-based microcontroller with a small OLED screen. 
  - a clickable rotary encoder that is the single input control
  - a TMC2209 stepper driver
  - 12v power input and a buck converter to feed the esp32
  - 12v output ports for 2 additional vibrators and an an H-bridge module to control them

The simple UI allows full control over the motion:

  - stroke duration
  - stroke amplitude
  - offset from the 0 position
  - motion path (just sinusoidal vs triangle wave so far)

The controls also allow control over the secondary vibrators for intensity, rhythm, and duty cycle.

It's been evolving for a couple years now and it works brilliantly!