Standalone Wiring Guide – Raspberry Pi Robot Car

Motor Driver Wiring

Pi GPIO inputs to driver control pins:

• GPIO17 → IN1
• GPIO18 → IN2
• GPIO22 → IN3
• GPIO23 → IN4
• Pi GND → Driver GND

Speed control (optional): Use PWM pins for PWMA / PWMB (TB6612FNG) or ENA / ENB (L298N) if you want speed control. Otherwise tie them high.

Motors → Driver

Left motor:

• OUTA1 → +
• OUTA2 → −

Right motor:

• OUTB1 → +
• OUTB2 → −

If a wheel spins backward, swap + and − for that motor only.

Power Wiring (Critical)

Motors + driver must be powered from a separate battery pack:

• Battery + → Driver VM / VIN / 12V input
• Battery − → Driver GND

Raspberry Pi is never powered from the motor battery. The Pi must use its own USB-C PSU.

Ground rule: Pi GND + Driver GND + Battery − + Sensor GND must be tied together.

Ultrasonic Sensor (HC-SR04)

• VCC → Pi 5V
• GND → Pi GND
• TRIG → GPIO24
• ECHO → GPIO25 through level shifter

Voltage Divider (required)

Use 2 kΩ + 1 kΩ to drop ECHO from 5V → 3.3V:

HC-SR04 ECHO → 2 kΩ → GPIO25
                 |
                1 kΩ
                 |
                GND
    

Never feed 5V directly into Pi GPIO pins.

Pin Map

Component	Signal	Pi GPIO / Power
Motor driver	IN1	GPIO17
Motor driver	IN2	GPIO18
Motor driver	IN3	GPIO22
Motor driver	IN4	GPIO23
Ultrasonic	TRIG	GPIO24
Ultrasonic	ECHO	GPIO25 (via divider)
Ultrasonic	VCC	5V
Ultrasonic	GND	GND
Driver + motor	VIN	Motor battery +
Driver + motor	GND	Shared ground

Pre-Power Checklist

• All grounds tied together
• ECHO level shifted to 3.3V
• Pi powered from USB-C PSU
• No motor power fed into Pi
• Motors spin freely
• No loose wire strands