How to Make a Bluetooth RC Car: Parts, Wiring, Code and App Control
A Bluetooth RC car is controlled from a phone over a short-range Bluetooth link. The simplest build uses a robot car chassis with two or four DC motors, a motor driver board (such as an L298N or TB6612FNG), a microcontroller (Arduino with an HC-05 module for Android, or an ESP32 with built-in Bluetooth), a battery pack, and a phone app that sends commands. The microcontroller reads letters or values from the app and drives the motors forward, backward and around turns.
By Kyle HilsonUpdated: October 20264 min read
Parts
| Part | Options |
|---|---|
| Microcontroller | Arduino Uno/Nano, or ESP32 (Bluetooth built in) |
| Bluetooth | HC-05/HC-06 (classic, Android) or BLE module/ESP32 (Android and iPhone) |
| Motor driver | L298N or TB6612FNG |
| Chassis | 2WD or 4WD robot car kit, or converted toy car |
| Battery | 2× 18650 Li-ion or AA pack, with switch |
| App | Bluetooth RC controller app or a custom app |
Classic Bluetooth vs BLE
HC-05/HC-06 modules use classic Bluetooth, which many Android apps support but iPhones generally don’t for this purpose. For iPhone control, use a BLE (Bluetooth Low Energy) module or an ESP32, with an app that supports BLE. Choosing the right one before buying saves frustration.
Wiring overview
- Motors to the driver’s outputs (left side and right side).
- Battery to the driver’s power input; common ground with the microcontroller.
- Driver control pins to microcontroller pins (with PWM for speed).
- Bluetooth module TX/RX to the microcontroller (use a voltage divider on 3.3 V module RX).
- Power the microcontroller from a regulated 5 V supply.
Step-by-step wiring with an Arduino is in how to make an RC car with Arduino.
The code
The program listens for commands from the Bluetooth module (for example F, B, L, R, S for forward, back, left, right and stop), then sets the motor driver pins accordingly. Many apps send these characters by default; others send joystick values that you map to motor speeds. Add a timeout so the car stops if no command arrives for a moment, which acts as a simple failsafe.
Choosing an app
Free “Bluetooth RC car” apps offer arrow buttons, joysticks or tilt control. Check what characters each button sends and match them in your code. Advanced builders write their own apps with tools like MIT App Inventor. Commercial phone-controlled cars are compared in can I control my RC car with my phone.
Troubleshooting
- Can’t pair: check the module’s name and PIN (often 1234 or 0000).
- Paired but no response: TX/RX swapped or wrong baud rate.
- Motors stutter: weak battery or voltage drops resetting the board.
- Car turns the wrong way: swap motor wires or change code.
- Short range: Bluetooth is limited to about 10–20 m; stay close.
Upgrades
- Servo steering for car-like handling.
- Ultrasonic sensor for obstacle avoidance.
- Headlights and horn.
- Speed control with PWM sliders in the app.
- Wi-Fi control with an ESP32 for longer range or camera streaming.
Powering it reliably
Most problems in first Bluetooth car builds come from power, not code. Two small DC motors starting at once can pull enough current to drop the battery voltage for a moment, and if the microcontroller shares that supply it resets, the Bluetooth link drops and the car seems to ignore commands. Use a battery that can deliver the current (two 18650 cells in series are a common choice), keep wires short and thick enough, and add a capacitor across the motor driver input. An L298N loses roughly two volts internally, so motors run noticeably slower than the battery voltage suggests; a TB6612FNG wastes far less and suits small builds better. Always connect all grounds together, and switch the battery off before changing wiring.
FAQ
What do I need to build a Bluetooth RC car?
A chassis, motor driver, microcontroller, Bluetooth module, battery and app.
Will an HC-05 work with an iPhone?
Generally no; use BLE or an ESP32.
How far does Bluetooth reach?
About 10–20 m in practice.
Can I convert a toy car?
Yes, by replacing its board with your electronics.
More on this topic: the complete RC Cars guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
