Objective
Build a two-wheel robot that follows a black line on a white surface without human control.
How it works
Two TCRT5000 sensors sit either side of the line. Each reports whether it sees dark or light. The Arduino reads both and steers: if the left sensor sees the line, slow the left wheel; if the right sees it, slow the right; if neither, drive straight.
Components you'll need
| Component | Qty | Availability | Price | |
|---|---|---|---|---|
 Arduino UNO R3 (compatible) | ×1 | In stock | $5.19 | |
 IR Sensor | ×2 | In stock | $1.18 | |
 Bo Motor | ×2 | In stock | $2.18 | |
 L298N Dual Motor Driver | ×1 | In stock | $2.29 | |
| 2WD Acrylic Robot Chassis | ×1 | In stock | $2.99 | |
 4×AA Battery Holder with Switch | ×1 | In stock | $0.59 | |
| Jumper Wire Set (120 pcs) | ×1 | In stock | $2.99 | |
| Bought one by one | $17.41 | |||
All of these come in Robo Obstacle Kit and ThinkNMake Maker Kit.
Circuit & connections
The full wiring diagram and pin-by-pin connections.
Code
The complete, tested sketch (20 lines), ready to upload.
Step-by-step instructions
6 illustrated steps:
- 1Assemble the chassis
- 2Mount the electronics
- 3Wire the motors
- 4Add the sensors
- 5Upload the code
- 6Tune
Troubleshooting
Fixes for the problems makers hit most often on this build.
