Ryan Malloy
e21219be8d
- Starlight documentation for mcnanovna and mcpositioner - 19 pages covering tools, prompts, hardware, and tutorials - Docker deployment with dev/prod modes - Makefile for docker compose management - Custom SVG logos and hero illustration
118 lines
3.3 KiB
Plaintext
118 lines
3.3 KiB
Plaintext
---
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title: Positioner Build Guide
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description: Build the ESP32 dual-axis antenna positioner
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---
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import { Steps, Aside } from '@astrojs/starlight/components';
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## Bill of Materials
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| Qty | Component | Notes |
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|-----|-----------|-------|
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| 1 | ESP32 DevKit | Any variant with enough GPIO |
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| 2 | TMC2209 stepper driver | UART mode, StallGuard support |
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| 2 | NEMA 17 stepper motor | 0.9° or 1.8° step angle |
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| 1 | 24V power supply | 3A+ for motors |
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| 1 | 5V regulator or USB | For ESP32 |
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| - | Wire, connectors | See wiring diagram |
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<Aside type="tip">
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The TMC2209 must be in UART mode, not standalone mode. This enables StallGuard sensorless homing and runtime configuration.
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</Aside>
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## Mechanical Assembly
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The positioner needs two axes of rotation:
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1. **Theta axis** (polar, 0-180°): Tilts the antenna from zenith to nadir
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2. **Phi axis** (azimuth, 0-360°): Rotates the antenna around vertical axis
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### Design Considerations
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- **Cable routing**: Ensure cables can handle full rotation without tangling
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- **Balance**: Center of gravity should be on the rotation axes
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- **Rigidity**: Minimize wobble for accurate measurements
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- **Range limits**: Mechanical stops for homing reference
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### Mounting Options
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| Approach | Pros | Cons |
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|----------|------|------|
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| 3D printed | Custom fit, cheap | Strength limits |
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| Aluminum extrusion | Strong, adjustable | Heavier, more complex |
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| PVC pipe | Very cheap, easy | Less precise |
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## Electronics Assembly
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<Steps>
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1. **Mount TMC2209 drivers**
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Install both drivers on a breakout board or custom PCB. Ensure proper heatsinking—these drivers can get hot under load.
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2. **Wire motor connections**
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| TMC2209 Pin | Motor Wire |
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|-------------|------------|
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| A1 | Coil A+ |
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| A2 | Coil A- |
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| B1 | Coil B+ |
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| B2 | Coil B- |
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<Aside type="caution">
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Never disconnect motors while powered—the back-EMF can damage the driver.
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</Aside>
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3. **Wire UART connections**
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Both drivers share the same UART bus but have different addresses:
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- Theta driver: Address 0x00
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- Phi driver: Address 0x01
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See [Wiring Diagram](/hardware/wiring/) for full pinout.
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4. **Power connections**
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- 24V to driver VMOT pins (motor power)
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- 5V/3.3V to driver VIO pins (logic power)
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- ESP32 powered via USB or separate 5V regulator
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5. **Test before mounting**
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Flash the firmware and verify both motors respond before final assembly.
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</Steps>
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## Firmware Setup
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See [Firmware](/hardware/firmware/) for build and flash instructions.
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## Calibration
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After assembly:
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1. **Home both axes**: Run `positioner_home(axis="both")`
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2. **Verify range**: Move to extremes and check for binding
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3. **Tune StallGuard**: Adjust `STALL_VALUE` in `config.h` if homing is unreliable
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4. **Set motion parameters**: Use `positioner_config()` to tune speed/accel
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## Troubleshooting
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### Motor doesn't move
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- Check power supply voltage (should be 24V)
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- Verify UART communication (TX/RX wiring)
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- Check TMC2209 address configuration
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### Homing fails (doesn't detect stall)
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- Increase motor current in `config.h`
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- Decrease homing speed
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- Adjust `STALL_VALUE` threshold
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### Motors get hot
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- Reduce motor current (if torque allows)
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- Add heatsinks to TMC2209
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- Reduce holding current when idle
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### Position drift
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- Check mechanical coupling (loose setscrews)
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- Verify microstepping is consistent
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- Check for missed steps (reduce speed/accel)
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