Question

Can the tone() and noTone() functions be used for digital communications?

(a) No, they cannot be used

(b) Yes, they can be used but only on certain Arduino Boards

(c) Yes, they can be used for all digital pins and Arduino Boards

(d) Yes, they can be used but only for certain pins

This question was addressed to me in class test.

This is a very interesting question from Advanced Input Output in portion Arduino Programming of Arduino

Answer 1

Right option is (c) Yes, they can be used for all digital pins and Arduino Boards

Easy explanation: The tone() function generates a square wave at a constant 50% duty cycle and a specified frequency. So, if a communication is to be established between two devices on this basis, the receiver only has to record the different frequencies of the square waves and map them to a certain set of finite predefined integers in order to obtain some meaningful data from the transmission.