e2fe9aa495
- Adjust stall current threshold to 4A and detection time to 2500ms - Add comprehensive README with hardware specs, wiring diagrams - Include current sensing circuit documentation and math - Improve motor and webserver implementations
109 lines
3.6 KiB
Markdown
109 lines
3.6 KiB
Markdown
# BTS7960 Motor Controller
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ESP32-based DC motor controller with web interface, using BTS7960 dual H-bridge driver with current sensing and stall protection.
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## Hardware
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### Components
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| Component | Model/Specification |
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|-----------|---------------------|
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| Microcontroller | ESP32 LOLIN32 Rev1 |
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| Motor Driver | BTS7960 Dual H-Bridge Module |
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| Power Supply | 12V DC |
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| Sense Resistors | 2× 1kΩ (for current sensing) |
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### BTS7960 Module Reference
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- [DeepBlue Embedded Guide](https://deepbluembedded.com/arduino-bts7960-dc-motor-driver/)
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- [BTN7960 Datasheet](https://www.infineon.com/dgdl/Infineon-BTN7960-DS-v01_01-EN.pdf)
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## Wiring
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### Motor Control Pins
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| BTS7960 Pin | ESP32 GPIO | Function |
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|-------------|------------|----------|
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| RPWM | GPIO25 | Forward PWM |
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| LPWM | GPIO26 | Reverse PWM |
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| R_EN | GPIO27 | Right Enable |
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| L_EN | GPIO14 | Left Enable |
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| VCC | 3.3V | Logic Power |
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| GND | GND | Ground |
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### Current Sensing Circuit
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The BTS7960 has IS (Current Sense) pins that output current proportional to motor load. A resistor converts this to voltage for ESP32 ADC.
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```
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BTS7960 Module ESP32
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┌─────────────────┐ ┌──────┐
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│ │ │ │
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│ R_IS (pin 7) ─┼──────┬───────┤GPIO34│
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│ │ │ │ │
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│ │ [R1] │ │
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│ │ 1kΩ │ │
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│ │ │ │ │
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│ GND ─┼──────┴───────┤GND │
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│ │ │ │
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│ L_IS (pin 8) ─┼──────┬───────┤GPIO35│
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│ │ │ │ │
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│ │ [R2] │ │
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│ │ 1kΩ │ │
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│ │ │ │ │
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│ GND ─┼──────┴───────┤GND │
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└─────────────────┘ └──────┘
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```
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| Connection | Details |
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|------------|---------|
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| R_IS → GPIO34 | Through 1kΩ resistor to GND |
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| L_IS → GPIO35 | Through 1kΩ resistor to GND |
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**Note:** GPIO34 and GPIO35 are input-only pins on ESP32, ideal for ADC readings.
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### Current Sensing Math
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| Parameter | Value | Formula |
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|-----------|-------|---------|
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| Sense Ratio | 8500:1 | I_sense = I_motor / 8500 |
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| Sense Resistor | 1kΩ | V_sense = I_sense × R |
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| At 4A motor current | 0.47V | (4 / 8500) × 1000 |
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| Max readable current | 28A | (3.3V × 8500) / 1000 |
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## Configuration
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Key settings in [`include/config.h`](include/config.h):
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| Setting | Default | Description |
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|---------|---------|-------------|
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| `STALL_CURRENT_THRESHOLD` | 4.0A | Current triggering stall detection |
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| `STALL_DETECT_TIME_MS` | 500ms | Duration before stall confirmed |
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| `PWM_FREQ` | 20kHz | PWM frequency (reduces motor noise) |
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| `CURRENT_SENSING_ENABLED` | true | Enable/disable in [`src/motor.cpp`](src/motor.cpp) |
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## Network
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| Setting | Value |
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|---------|-------|
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| WiFi SSID | tami |
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| Static IP | 10.81.2.185 |
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| HTTP Port | 80 |
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## Build & Upload
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```bash
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pio run # Build
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pio run -t upload # Build and upload
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pio device monitor # Serial monitor (115200 baud)
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```
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## Stall Protection
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When motor current exceeds 4.0A for 500ms continuously:
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1. Stall is detected
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2. Motor stops immediately
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3. Serial log: `STALL PROTECTION: Stopping motor (current: X.XXA)`
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To resume operation, send a new speed/direction command via the web interface.
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