Arduino Audio Button

Question

Hello,

This year in our 8th grade science class, I was in the advanced class and we referred to ourselves as the "smart class." One of my friends had a specific way of saying it that cracked my teacher up.

I have some Arduino experience and wanted to make a bare-bones system in an enclosure that when she pressed the button it played a recording of my friend saying "The Smart Class" in his voice.

How will I go about doing this with a bare bones system? I know I can get a mp3 player pcb from sparkfun but it is too expensive for this novelty item. I wanted to use an ATMEGA328 or similar. And how would a drive a small .5 ohm speaker and amplify it. Any and all help is appreciated.

Thanks,

Austin

Robert Peter Oakes · Accepted Answer

well you can use a pulse width modulated output to create the sound and drive a transistor to get the gain necessary to drive a small speaker

btw, speakers are not normally .5 Ohms, they would typically be 4, 8 or more ohms.

You would not need to smooth the PWM as the speaker would do that for you (Much like a class D amplifier)

the biggest issue is getting the recording into a format that can be sent to the PWM timer and also if it will fit within 32K along with a boot loader and basic routine to read a switch and output the binary stream,

If the sound bite is not too long it may well be doable which looking at your message should fit.

all of this could be done with a ATMEGA328 (32K program space)

You could also use 8 output pins (Or less) and create a simple R/2R digital to analog convertor but the issue still remains about digitizing the sound bite

Robert Peter Oakes · Answer

you could define it as a char[] long enough to hold the data as part of the program, then you just have to loop through it when the button is pressed

a char is 8 bits, same as a byte so as long as you have enough program space for it all, you good to go

Robert Peter Oakes · Answer

well that's where my current skills fade, I have not looked much at converting audio into a form consumable with an Arduino or other device

If I find something I will post it but I suggest you try google "Waveform convert to WAV from MP3" or something