Objective
To build a wireless RC car that can be driven from a smartphone over Bluetooth.
What you will learn
1. Bluetooth serial communication
2. Using the HC-05 module
3. H-bridge motor driver control
4. Controlling DC motor direction
5. Wireless control from a smartphone
6. Arduino programming
How it works
The smartphone app(install `Arduino Bluetooth control` app from Playstore) sends a single letter over Bluetooth:
F = Forward, B = Backward, L = Left, R = Right, S = Stop
The HC-05 passes the letter to the Arduino serial port. Arduino sets the IN1-IN4 pins of the L298N HIGH or LOW to spin the motors in the required direction. The L298N supplies power to motor power from the battery.
Components you'll need
| Component | Qty | Availability | Price | |
|---|---|---|---|---|
 Arduino UNO R3 (compatible) | ×1 | In stock | $5.19 | |
 L298N Dual Motor Driver | ×1 | In stock | $2.29 | |
| 2WD Acrylic Robot Chassis | ×1 | In stock | $2.99 | |
| Jumper Wire Set (120 pcs) | ×1 | In stock | $2.99 | |
 4×AA Battery Holder with Switch | ×1 | In stock | $0.59 | |
| Buzzer & Button Pack | ×1 | In stock | $0.69 | |
 HC-05 Bluetooth Module | ×1 | In stock | $2.99 | |
 Bo Motor | ×2 | In stock | $2.18 | |
| Bought one by one | $19.91 | |||
All of these come in ThinkNMake Maker Kit.
Circuit & connections
The full wiring diagram and pin-by-pin connections.
Code
The complete, tested sketch (50 lines), ready to upload.
Step-by-step instructions
8 illustrated steps:
- 1STEP 1
- 2STEP 2
- 3STEP 3
- 4STEP 4
- 5STEP 5
- 6STEP 6
- 7STEP 7
- 8STEP 8
Troubleshooting
Fixes for the problems makers hit most often on this build.
