If you need to add distance awareness to your robot or low altitude sensor for your drone, this is one of the easiest and most commonly used ways.

Specifications

• Power supply: 5V DC
• Quiescent current: <2mA
• Effectual angle: <15°
• Ranging distance: 2cm – 500 cm
• Resolution: 1 cm
• Ultrasonic Frequency: 40k Hz

Sequence chart

A short ultrasonic pulse is transmitted at the time 0, reflected by an object. The sensor receives this signal and converts it to an electric signal. The next pulse can be transmitted when the echo is faded away. This time period is called the cycle period. The recommend cycle period should be no less than 50ms. If a 10μs width trigger pulse is sent to the signal pin, the Ultrasonic module will output eight 40kHz ultrasonic signal and detect the echo back. The measured distance is proportional to the echo pulse width, and can be calculated by the formula above. If no obstacle is detected, the output pin will give a 38ms high level signal.