Building a Mini Arduino Robot: Start Small, Dream Big
Essential Parts and Practical Planning
Gather an Arduino Nano or Uno, a TB6612FNG motor driver, two micro metal gear motors with matching wheels, a small caster, HC-SR04 ultrasonic sensor, line sensors, a compact chassis, a 2S LiPo or NiMH pack, an on/off switch, a buck converter to 5V, M3 hardware, jumper wires, and heat-shrink. Snap a photo of your spread and share it with the community!
Essential Parts and Practical Planning
Decide on wheel diameter, gear ratio, and battery size early. Lightweight parts help, but leave space for wiring and sensor mounts. Aim for motors around 100–300 RPM for controllable speed. Keep your center of gravity low, and plan where the battery sits. Tell us your size choice and why—others will learn from your trade-offs.
Wiring and Electronics That Stay Reliable
Route battery voltage through an on/off switch to a buck converter for a stable 5V rail. Tie all grounds together. Add a large electrolytic capacitor and 0.1 µF decouplers near the Arduino and motor driver. Consider reverse-polarity protection with a Schottky diode or P‑channel MOSFET. Avoid brownouts by testing worst-case loads with wheels lifted.
Wiring and Electronics That Stay Reliable
The TB6612FNG is compact and efficient. Wire PWMA/PWMB to PWM-capable pins, AIN1/AIN2 and BIN1/BIN2 to digital pins, and connect STBY to 5V through the Arduino or directly. Cross the motor leads if your robot drives backward. Twist motor wires to reduce noise, and verify current draw with a meter before driving on the floor.
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Navigation: From Obstacle Avoidance to Line Following
Ultrasonic Obstacle Avoidance Made Friendly
Measure distance ahead and set a threshold to trigger a turn. Add a short reverse before turning to avoid snagging on obstacles. If you mount the sensor on a micro servo, scan left and right to pick a clearer path. Tell us your favorite avoidance routine, and we’ll feature clever snippets next week.
Line Following with a Taste of PID Control
Calibrate sensor values on white and black, compute an error from the line center, then use Kp, Ki, and Kd to adjust motor speeds. Start with proportional only, then add derivative to smooth oscillations. Many readers found Ki optional on short tracks. Share your best Kp/Kd pair and track photos.
Blending Behaviors with a Simple State Machine
Define states like IDLE, CRUISE, AVOID, and FOLLOW_LINE. Prioritize safety by letting obstacle avoidance override other modes. Use timers to prevent getting stuck in loops. A tiny state diagram on a sticky note keeps logic sane. Post your diagram—your structure might inspire another maker’s breakthrough.
