Purpose:
The purpose of this project was to try our hand at producing
audio through Arduino. After spending the majority of the year on temperature
we decided that looking into sound would be a great way to finish the year on a
high. As we got deeper into the project it became less about trying to produce
sound as to trying to improve the somewhat weak code that we were provided. The
project then became a problem solving assignment as well as a test of our
creativity based on what we wanted/were determined to add.
Procedure:
We first looked at the circuit design that was in 30 Projects for the evil Genius and
after getting a general understanding we built it. Then we looked at the Tune
Player code from 30 Projects for the Evil
Genius to get a sense of how the sounds were created and the method in
which the author used to play songs. After we had a better understanding of the
code that was provided we uploaded the sketch and ran it. We noticed right away
that the tune player was not what we expected to hear. We thought about ways to
improve it such as adding sharps, multiple octaves, and different note
durations. After completing all the improvements we ran the new sketch and the
difference was amazing.
*IMPORTANT*
The array sin16[.......] in my Arduino sketch is VERY important. It simulates a sin wave. Because we are using a 4 bit amplifier we can only get a maximum of 16 points on our sin wave. 7 being the middle, 15 being the maximum and 0 being the lowest (0-->15 = 16....dont be off by one). The matrix toneDurations[3]12]{...} determines the rate at which we run through the sin wave, hence the name toneDurations. It does not produce the sin wave but instead determine the frequency of the wave, therefore producing the pitch.
Parts List:
1 100nF non-polarized capacitor
1 100uF, 16v electrolytic capacitor
5 10k ohm resistors
3 4.7k ohm resistors
1 1M ohm resistor
1 100k ohm resistor
1 TDA7052 1W audio amplifier
Miniature 8 ohm loudspeaker
Check out R2R Digital to Analog converter overview
