Build guide
Everything below is a starting point from the design pack. All dimensions and settings are estimates until measured on a real window.
1. Print
Parts per window: knob cup + TPU liner, motor hub/clutch, housing base and lid, anti-rotation tail; one controller box (base + lid) for the pair. Print in matt white PETG (or ASA — it tolerates the summer heat inside the window niche better). The pack documents layer heights, infill and orientation per part in the repo's docs/ASSEMBLY.md. Print a small colour sample first and compare it to the knob in daylight.
STLs ship with the repository downloads under the default (estimated) parameters. Because the CAD is parametric OpenSCAD, you change the measurement constants at the top of each .scad file and re-export — the CI re-renders every part and refuses to merge meshes that are not manifold.
2. Assemble the head
- Snip the motor's mounting ears flush (keep the gear case closed).
- Bipolar-mod the stepper coil wiring for the TMC2209 (documented in
electronics/ELECTRONICS.md). - Press the hub onto the motor's D-shaft and fit the O-ring; the cup rides on the hub through the clutch.
- The TPU liner's slits take up the knob's taper — swap liner thickness if the grip is off.
3. Wire and flash
- Populate the controller on perfboard per
electronics/schematic.png: USB-C 5 V input with a polyfuse, XIAO ESP32C6, two TMC2209 modules addressed by stride pins, calibration button, LED with a filament light pipe. - Set driver VREFs low as a backup; the firmware sets real currents over UART.
- Flash
firmware/(ESP-IDF + esp-matter, ESP32-C6 target) — the repo README links the commands. Firmware is CI-compiled in this project but not yet hardware-tested — treat the first flash as bring-up, not plug-and-play. - Never plug or unplug a motor while powered.
4. Install
- Route the flat cable with small white adhesive clips (or paintable mini-channel) and connect the head with its detachable connector.
- Push the head gently up over the knob — never lift the knob itself; the shaft and clip joint above it are fragile.
- Slide the tail saddle over the existing hook cleat (or fit the VHB face tab on a cleaned frame spot).
- Open the sash fully and confirm nothing touches; lift cords must hang free.
5. Calibrate and commission
- Hold the box button 3–10 s: guided calibration walks the blind slowly to closed-up, closed-down and horizontal — you press once at each point. Span is stored on the device.
- Commission in your Matter app (scan the onboarding code from the log). Assign the two tiles to your rooms; 0 % = slats horizontal, 100 % = closed.
- After anyone turns the knob by hand, button-hold 1–3 s re-homes the head.