Sending Data through Headphone jack in Android phones

Question

I\'m currently dealing with a new project and I have to send data through headphone jack with specific voltage, then i can work on that voltage.

so here i need to progra

Answer 1

you could maybe try turning your data into binary for example when your listening to music your head phone jack changes +- vibrating to make a sound so you could make +- = 0 and -+ = 1