imrishabh18/rp2040-motor-controller

mechanical/README.md

# NEMA 17 rear-mounted controller

The outline follows the PD-Stepper V1.1 Gerber perimeter from joshr120/PD-Stepper, commit `3c40073a0ec51653f6ea48c70f365bd7f9f3bdcc`:
https://github.com/joshr120/PD-Stepper/tree/3c40073a0ec51653f6ea48c70f365bd7f9f3bdcc/PCB

- Overall outline: approximately 42.30 × 42.32 mm.
- Four mounting centers: (±15.5, ±15.5) mm, giving a 31 × 31 mm square.
- Mounting drill: 3.3 mm. Grounded 5.6 mm copper rings; placement reserves a 6.5 mm screw-head clearance circle.
- The perimeter's 3 mm corner transitions are approximated with 12 straight segments per 45-degree arc (maximum deviation approximately 0.002 mm).
- Component side faces away from the motor. Use insulated spacers; do not rest solder joints directly on the metal motor end plate.
- A 6 mm spacer is the design assumption. Verify it clears the particular motor's rear shaft/bearing boss and the assembled board's leads. Screw length depends on motor length and the spacer/cover stack.
- The reference cover/heatspreader is not interchangeable: this design has different components, connector openings and thermal-contact positions.
- Motor connector: four-pin JST PH, 2 mm pitch, A+, A−, B+, B−. This requires a matching cable in place of the original screw-terminal connection.

NEMA 17 describes the motor frame; check the actual motor's rear fasteners before ordering boards. The reference uses replacement motor tie screws. The PCB measures nearby driver-board temperature, not winding temperature.

The sampled perimeter is adapted from the PD-Stepper V1.1 Gerbers. The upstream GPL-3.0 license is included as `PD-Stepper-LICENSE`. This repository contains the modified outline source.