Bluetooth Remote-Controlled (RC) Car with Smartphone Joystick App
Transform a 4WD rover chassis into a smartphone-controlled RC car using an ESP32 / HC-05 Bluetooth module and an Android/iOS virtual joystick interface.
Build your own custom remote-controlled vehicle! Learn how to establish wireless Bluetooth serial communication, parse joystick X/Y velocity packets in firmware, and drive dual H-Bridges with smooth acceleration curves and LED headlights.
Bill of Materials (BOM) & Components
| Component | Specifications | Qty | Estimated Cost |
|---|---|---|---|
| 4WD / 2WD Smart Robot Chassis with DC Motors | Motors, wheels, acrylic plates, hardware | 1 | $14.00 |
| ESP32 DevKit V1 (with built-in Bluetooth) or Arduino + HC-05 | Receives wireless commands and controls motors | 1 | $6.00 |
| L298N Dual H-Bridge Motor Driver | 2A continuous dual-channel motor control | 1 | $4.00 |
| 7.4V 2S 18650 Li-ion Battery Pack with Holder | Powers motors and microcontroller | 1 | $6.00 |
| White & Red 5mm LEDs (Headlights & Taillights) | Controllable via smartphone button triggers | 4 | $1.00 |
Electrical & Architecture Summary
ESP32 Bluetooth Serial receives directional characters or joystick coordinates over Bluetooth Classic / BLE. Motor PWM pins are modulated to achieve differential skid-steering.
Step-by-Step Assembly & Configuration
Chassis Wiring & Motor Driver Setup
Mount the 4 DC motors onto the chassis. Wire left motors in parallel to Output A on the driver, and right motors to Output B.
- Verify both left wheels spin forward when Output A is energized.
- Connect motor driver ground to microcontroller GND.
Flashing Bluetooth Firmware & App Pairing
Flash the Bluetooth serial parser sketch. Download any free Bluetooth RC Controller app from the Google Play / iOS App Store and pair with `MyRoboPath_Car`.
- Map app controls: Forward ("F"), Reverse ("B"), Left ("L"), Right ("R"), Stop ("S").
- Test wireless range (reliable up to 15 meters indoors).
Adding Headlights & Speed Control
Connect front LEDs through 220Ω resistors to digital pins, enabling remote headlight toggles from your phone.
- Add horn buzzer on digital pin 8.
- Implement 3-speed transmission modes (Low, Medium, Turbo Boost).