Finally have the Arduino, capacitors, and the SOMO 14-D.  Still need to figure out what micro-SD memory card to get for the SOMO as not all are compatible.

Computer Controlled Amplifier

• To reduce number of problems, the oscillator circuit will be used to produce the sound.  Later this will be replaced with the SOMO 14-D.
• Fried first amplifier because I had the pin numbering wrong.  Pin numbering on ICs is numbered down on the left side then up on the right side.  For some reason I thought it was down on both sides and got the VCC and GND pins reversed causing smoke.
• The capacitor used to filter the audio signal is not supposed to be polar but a polar capacitor will work as long as, the positive side is on the pin and the negative side goes to the audio source.  This seems strange considering the direction of the current but when I had it the other way no sound came out.  Luckily the audio signal isn’t strong enough to blow the capacitor.
• Switched piezoelectric speaker with regular speaker to make sure it wasn’t causing problems due t it having a higher resistance
• Realized that when the amplifier was changing volume the sound light sound would cut off.  I figured this was due to lack of power.  Took the whole circuit off the i2c-usb controller’s power and onto the power supply.
• Was not able to change the resistance on the the rheostat chip.  Realized that all i2c controlled chips must be grounded to the i2c controller gnd.
• Test class worked for controlling volume!
• The amp has to be muted digitally in order to get absolute silence.  The piezoelectric speaker, due to having a higher internal resistance, can be adjusted down to being “muted” without having to control the mode of the amplifier.
• The piezoelectric speaker seems to work well.  Not sure how good it will be for playing sounds, instead of tones.  Need to find out if I can get samples of those tiny speakers I mentioned in a previous post.

Arduino

• Considering part of the goal is to reduce the number of usb devices(not a very important goal but still), the mega would have probably been better then the Uno.  That said, the uno should be useful to see if it will work for our application, and should have enough outputs for a two finger prototype.  Another advantage of the mega is it can speak i2c which would eliminate the need for the usb-i2c adapter.  However, if I find its better to control the mute function on the amplifier with the second rheostat on the variable resistor chip, we will need two i2c channels in order to communicate with 5 amplifiers.
• Before I attempt to get the Arduino to communicate with the SOMO 14-D, I am going to try some basic tutorials to make sure I understand how to program it.

Speakers

• Spoke to a representative at Murata to see if we could get samples of the VSLBP2115E1200-T0.  He directed me to a local distributor Glen White Associates(434-385-6110).  He also said that the Speakers should be used with a audio amplifier for ceramic speakers.  There is no problem with using a regular amplifier but it may not be loud enough due to the higher impedance.