Jaycar Arduino-Compatible Dual Ultrasonic Sensor Module – HC-SR04, 2cm–450cm Range

Your robot's about to walk into the coffee machine again. This HC-SR04 ultrasonic module gives your Arduino a pair of eyes that see up to 4.5 metres in front of it, with a beam narrower than 15 degrees so it doesn't pick up the wall behind the obstacle. Two digital pins – trigger and echo – and you're reading distance in microseconds. No analog-to-digital conversion, no extra library beyond the standard NewPing or Ultrasonic. Mount it on a servo for a sweeping SONAR array, or fix it at the front of a rover for straightforward obstacle avoidance. At 45 × 20 × 13 mm it bolts to a chassis without hogging space. Detection starts at 2 cm, so a low shelf edge won't ghost through. Solder four wires, wire up, and your build stops bumping furniture

• HC-SR04 sensor IC – measures 2 cm to 450 cm with <15° beam angle
• Uses just two digital pins (trigger + echo) – no ADC needed
• Operating voltage 0.5 V as specified; verify against your board's rail before powering
• 45(W) × 20(D) × 13(H) mm module – mounts flat on a chassis or behind a panel
• Ideal for robotics obstacle avoidance, servo-mounted SONAR, or level sensing