LM358 Audio Input Sensor

Self-Balancing Bot

A two-wheeled self-balancing robot using ESP32, MPU6050 (accelerometer + gyroscope), TB6612FNG motor driver, and Bluetooth gamepad control via Bluepad32.

Hardware Requirements

Pinout

ESP32          TB6612FNG          MPU6050
────────────────────────────────────────────
GPIO 33   →    PWMA
GPIO 14   →    AIN1
GPIO 15   →    AIN2
GPIO 32   →    PWMB
GPIO 26   →    BIN1
GPIO 27   →    BIN2
GPIO 21   →    SDA
GPIO 22   →    SCL
3.3V      →    VCC
GND       →    GND

Firmware Files

Codes/P1/P1.ino — Original Version

Status: Reference implementation (has placeholder values)

Features:

• Basic PID balance control (100Hz loop)
• Complementary filter for sensor fusion (MPU6050 accel + gyro)
• Bluetooth gamepad control via Bluepad32
• TB6612FNG motor driver interface
• Fall detection safety cutoff (>45°)

Known Issues:

• ❌ Kp, Ki, Kd, base_setpoint set to Add_Values_Later — won't compile
• ❌ No calibration routine — base_setpoint must be manually tuned per robot
• ❌ No integral anti-windup — causes overshoot after disturbances
• ❌ No motor deadband compensation — motors stall at low PWM
• ❌ No gamepad deadzone — joystick drift causes unwanted movement
• ❌ No controller watchdog — robot keeps moving if controller dies
• ❌ No MPU6050 verification — silent failure if sensor disconnected
• ❌ No serial telemetry — blind PID tuning

Codes/P1/Program2.ino — Optimized Version

Status: Production-ready with all fixes

All Original Features Plus:

PID Tuning Guide (Program2)

Open Serial Monitor at 115200 baud. You'll see:

Angle: 0.12 | Setpoint: 0.00 | Out: -15.3 | P: -3.0 I: -0.2 D: -12.1

Tuning Order:

1. Kp only (set Ki=0, Kd=0): Increase until sustained oscillation, then reduce ~30%
2. Kd: Add to dampen oscillations (start ~0.5-2.0)
3. Ki: Small value (0.5-2.0) to eliminate steady-state drift

Tips:

• Hold robot upright during 2-second calibration (LED on ESP32 blinks during this)
• Test on carpet first — smoother surface = easier balance
• If robot falls backward consistently, increase base_setpoint slightly (or add weight forward)
• Kp typically 20-50, Kd 0.5-3, Ki 0.5-2 for this hardware

Building & Flashing

Arduino IDE

1. Install ESP32 board package: https://dl.espressif.com/dl/package_esp32_index.json
2. Install Bluepad32 library via Library Manager
3. Open Program2.ino, select board ESP32 Dev Module, upload

PlatformIO (Recommended)

; platformio.ini
[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
lib_deps =
    ricardoquesada/Bluepad32 @ ^2.0.0
monitor_speed = 115200

Troubleshooting

License

MIT — Feel free to use, modify, distribute.