Radio Transmitter , Range 15 - 20 meters , underwater wireless communication , Help with schematic

Thread Starter


Joined Jun 4, 2018
Does the 555 chip also tune the circuit to a specific frequency ? Is this possible . Also I still dont understand what happens with the piezo element sensor that detects the ultrasonic waves . How does the tuning to this cirquit happen ? Adding weight increases only sensitivity or also tunes the reciever ?


Joined Aug 14, 2018
You can regard the piezo elements as speaker/microphone. They just convert the electrical signal to ultrasonic signal or vice verse. For the receiver, you need to tune the capacitor or inductor to let the LC resonance frequency to the the same as the carrier frequency, just like the legend AM/FM radios.