Core theory
Theory of a 2-Wheeled Robot
Understand motion, power, sensors, signals, and decision loops before wiring.
The robot loop
A robot repeats a simple loop: sense, think, act, check. Sensors collect facts, Arduino Nano decides, L293D powers the motors, and the robot checks the result again.
For grade 3-5: think of the Arduino Nano like the class captain that listens and gives instructions. For grade 9-12: this is a feedback-control loop.
Motion theory
| Motor state | Robot motion |
|---|---|
| Left forward + right forward | Forward |
| Left backward + right backward | Reverse |
| Left slow + right fast | Curved left |
| Left backward + right forward | Spin left |
Do and don't
Do
- Use Arduino Nano as the controller.
- Keep battery negative and all module GND pins connected.
- Test motors with wheels lifted first.
- Use a voltage divider for HC-05 RX if Arduino TX is 5 V.
- Power servo from a stable 5 V source.
Don't
- Do not short Li-ion cells.
- Do not connect motors directly to Arduino Nano pins.
- Do not mix loose wires without labels.
- Do not run high motor speed during first tests.
- Do not assume every RF module has the same pinout.