The HC-SR04 is a great ultrasonic range sensor, as it has an operating range between 2 - 500cm with a 30-degree effectual angle!
Specification:
- Power supply: 5V DC
- Effectual angle: < 30 degrees
- Ranging distance: 2cm to 500 cm
- Resolution: 1 cm
- Ultrasonic Frequency: 40k Hz
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