Simple demo of 'tone dial' technique. Click the buttons to make some good old telephone sounds! Whenever you click a button (or press it on your keyboard), you will: ‣ hear its DTMF tone, ‣ see the audible frequencies flash up in red. WARNING The sound generated by this project, when picked up by the open receiver of a telephone, may actually dial a phone number. This can be a fun experiment, but please be careful whose number you dial.
Every tone consists of 2 frequencies, as explained here: https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling The project contains 24 sprites: 16 for the buttons, 8 for the wires. Their position on the stage is essential: each button should have two wires crossing it. Clicking a button activates the sound in both touching wires. Notice this is a perfect use case for the 'touching color' sensing block! SOUND Each wire has its own (single-frequency) sound, created using SoX (http://sox.sourceforge.net/), as follows: sox -n <filename> synth 0.25 sine <frequency> GRAPHICS Buttons: Scratch library. FONTS Donegal for the star, Helvetica for everything else. BUGS Pressing star (*) or hash (#) on your PC keyboard has no effect; you must use the mouse to press these buttons. SIMILAR PROJECTS https://scratch.mit.edu/projects/254080/
