I am *incredibly* excited about adding a mini MP3 trigger to the community book I am making. What this means is that whilst making the artwork for the pages of book, we can also record short sound bites and then play them back in the book through some mini speakers. The trigger has 18 tracks, each track is connected to a pin. It plays the track when the circuit to corresponding pin is closed (i.e. when you press a button in the book).
Of course I have not been doing this on my tod, I have had help from (the brilliant) Seb Madgwick, who is an expert in these matters. In fact, this was like a walk in the park in comparison to the kind of projects he usually works on (but fun I hope!).
This is the MP3 we are using. It is a standard MP3 trigger that you can get from Sparkfun. It’s nice and slim and will fit very neatly in the book. I have drawn the diagram to show what each bit does. I’m afraid I am not sure what all the parts of the circuit board do (see digram ->”not sure”). I am assuming the processing is happening in these centipedesque microchips, but will find out for shiz and let you know.
We customised the board by changing the power source to 3.7volts. Seb is an fantastic solderer and gave me some good pointers (yes, I soldered these bits!).
We also replaced the the low dropout regulator (pictured below), because it was not working properly with the new power source we added. Well. Hacktually Seb did this as it was pretty fiddly as you can see.