ESPHome-based automatic blind control system using the PD-Stepper controller board by ThingsbyJosh.com.
This project provides a complete solution for automating window blinds with precise stepper motor control. It includes 3D-printable mounting hardware, a custom power distribution PCB, and ESPHome configuration for seamless Home Assistant integration.
- PD-Stepper Kit - ESP32-based stepper motor controller (includes board, encoder magnet, aluminium spacer and heatsunk)
- Stepper Motor - NEMA 17 or compatible
- Custom Power PCB - Distributes power to the PD-Stepper board via spring terminals connected to internal pads
- 3D-Printed Mounting Hardware - Complete blind mounting assembly
- M3 Hex Standoffs and Nuts - For assembly (example)
- M3 Countersunk Bolts, 15mm and 22.5mm - For mounting (example)
- JST-PH 2.0mm Connectors - 3-pin connectors for power PCB (example)
- 2mm Acrylic Rod - For light guides (example)
Power is supplied through a custom PCB that connects to internal pads on the PD-Stepper board using spring terminals, eliminating the need for external connectors.
The mounting hardware consists of multiple printed parts that work together to create a complete blind mounting assembly.
Motor Housing and Gear
- BasePlate - Main mounting base
- Outer - Outer housing component
- Inner - Inner housing component
- Cover - Top cover
- Gear - Drive gear for blind mechanism
Installation Template
- Motor Cavity Template - Template for positioning screw holes and motor cutout in the window frame
PCB Assembly Jig
- JigOuter - Assembly jig outer piece
- JigSpacer - Assembly jig spacer (for soldering socket onto PCB)
- Source File -
3d-design/BlindMount.FCStd(FreeCAD format) - STL Files - Individual parts in
3d-design/STL/ - 3MF Files - Individual parts in
3d-design/3mf/
See power-pcb/README.md for PCB assembly instructions.
| Power PCB | Assembled PCB |
|---|---|
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- Prepare the 3D-printed Outer piece by pushing two half-width M3 nuts into diagonally opposed holes, then pushing the power PCB into its slot on the other side.
- Attach the PD-Stepper board to the aluminium spacer using the sticky heat transfer pad, and loosely place the Cover piece on top.
- Apply the Outer piece to the back of the PD-Stepper board so that the spring terminals make contact with the power and NTC pads.
- Screw together using two 15mm countersunk bolts.
- Cut sections of the acrylic rod to use as light guides, and push them gently into the holes for the blue and red LEDs.
- Finally, affix the heatsink to the full assembly through the gap in the Cover.
| Exploded View | Bottom | Top |
|---|---|---|
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- Using JST-PH 2.0 connectors, build a 4-pin to 6-pin cable which works for your motor, matching either the straight-through or crossover cables from the PD-Stepper kit which won't be long enough to reach.
- Test the motor and cable using your completed outer assembly.
- Pass the motor cable through the cable hole, then attach the Base Plate to the motor using the hex standoffs. Use two short (5-6mm) standoffs in the corners where the Outer assembly is screwed together, and two longer (8mm) standoffs in the corners which will be used to screw the Inner to this piece.
- You will have to turn the standoffs by a few degrees to the correct orientation such that the Inner piece fits over them. The Inner piece itself can be used as a spanner for that purpose. The Inner piece then pushes over the standoffs and guide posts.
- Offer the Outer assembly up to this to check that it all fits together.
| Aligning the hex standoffs | Motor Assembly |
|---|---|
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- Push the Gear onto the motor shaft, pushing it fully home until the centre of the Gear is aligned with the centre of the guides in the Inner (and Outer) pieces and the cord will flow freely.
- The centre of the Gear is fully round for 2.5mm at the back and then has a flat part. This is fully parameterised in the spreadsheet in the FreeCAD model, if you need to adjust it or make the Inner piece thicker to allow for a longer shaft.
- You may also need to trim the motor shaft so that there is sufficient space to install the encoder magnet. The easiest way to do this is to install a Gear and then use a Dremel to cut through both Gear and motor shaft at the right point. I kept the motor turning as I did this to ensure a smooth cut.
- Push the encoder magnet from the PD-Stepper kit into the front of the Gear as shown. It should push fully home and be a relatively snug fit. If you have a metallic blind cord, note that the magnet may sometimes prefer attaching itself to the blind cord rather than staying in the Gear where you put it.
| Trimmed gear shaft | Gear with magnet |
|---|---|
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- Two 22.5mm bolts go through the other corners of the Outer assembly to secure it to the Base Plate, with the blind cord inside. Bolts of that length are hard to come by; you may find that 20mm is just about enough, but I used 25mm bolts and the Dremel.
- The 3-pin JST-PH plug is shown connected to the Power PCB in the Outer Assembly. You may prefer to use all black for the visible part, and/or apply heatshrink. As shown in the images, the pinout is:
- Black: GND
- Red: +5V to +20V
- Yellow: Reed switch, closed to GND when the blind is fully open (optional).
| Assembled Units | Connector Wiring |
|---|---|
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For instructions on mounting the completed assembly into your window frame, see INSTALLATION.md.
ESPHome configuration examples are provided in the esphome/ directory. The landing-blind-1.yaml file shows a complete configuration with the following substitutions:
- name - Device name for ESPHome and Home Assistant
- encoder_closed_pos - Full blinds length in encoder counts (adjust to suit your setup)
- encoder_direction - Which direction is towards 'closed' (1 or -1)
- motor_direction - Motor direction relative to encoder (1 or -1)
- microsteps - Microstepping setting for the stepper driver
- run_current - Motor run current (e.g., "100m" for 100mA)
- max_speed - Maximum motor speed
- stallguard_threshold - StallGuard threshold for stall detection
- pd_voltage - Power delivery voltage (unused)
On power-up, the controller will assume that the blinds are open. The first time it is asked to open the blinds, it will perform a rehoming operation, running at half-speed until it stalls. It will close the blinds at sunset, and open the blinds at 07:30AM or sunrise, whichever is later.
You can tweak the current, speed and stallguard settings to suit your blinds and motor, so that the stall is detected correctly. The motor_direction may differ for supposedly identical installations, if your motor cables are wired differently. Some notes on calibration are in the top of the blind.yaml file.
The third pin on the power connector is for a reed switch, which connects that GPIO pin to ground when the blind is fully open. This is not necessary, because rehoming works well with properly calibrated stall detection anyway. One thing that a reed switch would allow is for the device to be sure, on startup, that it is at the home position and to initiate a rehoming if not. Rehoming on startup is disabled because when starting from the home position, the immediate stall... well, isn't immediate enough, and is noisy.