568339367e
Instead of seeding EMA with first reading after stabilization, now continuously update EMA during the 500ms stabilization window. This ensures EMA represents normal running current rather than potentially high stall current if motor hits end stop immediately.
BTS7960 Motor Controller
ESP32-based DC motor controller with web interface, using BTS7960 dual H-bridge driver with current sensing and stall protection.
Hardware
Components
| Component | Model/Specification |
|---|---|
| Microcontroller | ESP32 LOLIN32 Rev1 |
| Motor Driver | BTS7960 Dual H-Bridge Module |
| Power Supply | 12V DC |
| Sense Resistors | 2× 1kΩ (for current sensing) |
BTS7960 Module Reference
Wiring
Motor Control Pins
| BTS7960 Pin | ESP32 GPIO | Function |
|---|---|---|
| RPWM | GPIO25 | Forward PWM |
| LPWM | GPIO26 | Reverse PWM |
| R_EN | GPIO27 | Right Enable |
| L_EN | GPIO14 | Left Enable |
| VCC | 3.3V | Logic Power |
| GND | GND | Ground |
Current Sensing Circuit
The BTS7960 has IS (Current Sense) pins that output current proportional to motor load. A resistor converts this to voltage for ESP32 ADC.
BTS7960 Module ESP32
┌─────────────────┐ ┌──────┐
│ │ │ │
│ R_IS (pin 7) ─┼──────┬───────┤GPIO34│
│ │ │ │ │
│ │ [R1] │ │
│ │ 1kΩ │ │
│ │ │ │ │
│ GND ─┼──────┴───────┤GND │
│ │ │ │
│ L_IS (pin 8) ─┼──────┬───────┤GPIO35│
│ │ │ │ │
│ │ [R2] │ │
│ │ 1kΩ │ │
│ │ │ │ │
│ GND ─┼──────┴───────┤GND │
└─────────────────┘ └──────┘
| Connection | Details |
|---|---|
| R_IS → GPIO34 | Through 1kΩ resistor to GND |
| L_IS → GPIO35 | Through 1kΩ resistor to GND |
Note: GPIO34 and GPIO35 are input-only pins on ESP32, ideal for ADC readings.
Current Sensing Math
| Parameter | Value | Formula |
|---|---|---|
| Sense Ratio | 8500:1 | I_sense = I_motor / 8500 |
| Sense Resistor | 1kΩ | V_sense = I_sense × R |
| At 4A motor current | 0.47V | (4 / 8500) × 1000 |
| Max readable current | 28A | (3.3V × 8500) / 1000 |
Configuration
Key settings in include/config.h:
| Setting | Default | Description |
|---|---|---|
STALL_CURRENT_THRESHOLD |
4.0A | Current triggering stall detection |
STALL_DETECT_TIME_MS |
500ms | Duration before stall confirmed |
PWM_FREQ |
20kHz | PWM frequency (reduces motor noise) |
CURRENT_SENSING_ENABLED |
true | Enable/disable in src/motor.cpp |
Network
| Setting | Value |
|---|---|
| WiFi SSID | tami |
| Static IP | 10.81.2.185 |
| HTTP Port | 80 |
Build & Upload
pio run # Build
pio run -t upload # Build and upload
pio device monitor # Serial monitor (115200 baud)
Stall Protection
When motor current exceeds 4.0A for 500ms continuously:
- Stall is detected
- Motor stops immediately
- Serial log:
STALL PROTECTION: Stopping motor (current: X.XXA)
To resume operation, send a new speed/direction command via the web interface.