Building a voice module that reads the serial output of a multimeter is a noble cause, even if it isn't particularly cost effective.
Mastro Gippo's friend, who is blind, had asked him for his help in locating a multimeter that could speak. What Mastro found was that they were quite expensive. The only meter he located cost over $2,000. Being the kind of guy who builds things in his spare time, he decided he wasn't going to just accept that cost, he would build one instead.
He knew he could find a relatively cheap multimeter with serial output. His idea was to read the serial output with an Arduino, then spit out the corresponding audio. Ideally, this would all be packaged in a nice little container for portability.
Mastro was in luck. He found a small MP3 player that could charge over USB, had a built-in speaker, auxiliary input, and extra space in the case. He ripped open the MP3 player, crammed in his Arduino Pro Mini and SD card reader, and reassembled it. By using the Super Simple SDaudio Library, he was able to get the audio output he needed for the MP3 player.
As you can see in the video, the entire setup seems to work quite well. I don't speak Italian, so I can't vouch for the enunciation of the spoken words, but it sounds loud enough, and the package isn't too cumbersome.
Of course, after he was finished, he noticed that there are, in fact, several cheap speaking multimeters on the market. At this point, that has become somewhat irrelevant!
— Caleb Kraft, Chief Community Editor, EE Times
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