I tried to make a low footprint controller with just 3 fader inputs running on 'linear rails' (PLA bushings).
This is part of another project -
An online drawing app that let's you change colors via MIDI ControllerConvential low cost faders usally feel a little stiff, as part of an ease in/out feature I guess.
With the drawing app you change all 3 color inputs constantly and with just one Finger, so you want them to run as smooth as possible.
Some of you might be interested in the related notes and building files.
- Arduino Beetle (AtMega32u4) with 3 analogue pins
- ground down potentiometer tracks to 0.2mm
- 2mm rails, overall height is 5mm
- carbon resistor tracks can't be soldered, had to mechanically fasten them with M1 screws. If someone knows a PCB service that will make 0.2mm PCBs with printed carbon resistors, let me know.
- the tracks are very heat sensitive with weird failure state (partially working)
- make one hole of the wiper carriage square and oversized, as done on commercially faders with linear rails, to make them more tolerant against misalignment of the rails.
- soldering enameled copper wire is a pain, I butchered the prototype until I discovered headphone cables
- made an USB cable from 4 core headphone cable (1.5mm) too, nice for such a light device.
- first layer typo is generated and exported as gcode via Sverchok, a Blender addon for parametric design
- arduino sketch has a multi-map function that allows you to remap the analogue readout in a non-linear way, I converted logscale potentiometers this way, losing resolution, but okay for this application.
