The range of ultrasonic is more than the 20khz
Then why does the HC-SR04 states 40hz what is it??
in datasheet it is specified as working frequency?
Also the frequency of sound depends on the medium
then what is this 40Hz?
Electronic – Ultrasonic HC-SR04
sensorultrasound
Best Answer
Looks like a typo.
The frequency of the ultrasonic is specified as 40kHz, and they recommend no shorter than 60ms between trigger pulses (16.7Hz)