Repairing the hand:

• Index finger still has problems.  Found out it was actually the bottom, not the top, that had the wrong resistance.  Attached a new one waiting for glue to dry.

I2C volume control:

• Found out the difference between a rheostat and a potentiometer.  A rheostat only has 2 leads while a potentiometer has 3.  The potentiometer changes the resistances between the wiper and both ends producing two different resistances which add up to the total.   All potentiometers can act as rheostats but rheostats can’t act as potentiometers.
• Our i2c chips are rheostats which is a problem because our amplifier needs a potentiometer.  I was able to mimic a potentiometer by setting the second register to (255 – register1).  This worked but there is no way to cut off the sound completely.  The chip has a shutdown command but it shuts it down at A which doesn’t exist on these circuits.
• There is a version of this chip which is a potentiometer and the cut off switch would work but these are not addressable.  To use these I would either need a usb hub or some type of i2c multiplexer which I am still confused how you actually address it.
• The other option is to get a complete audio amplifier IC.  Finding one of these that is not tiny and has leads is hard.
• Going to read documentation for the ad5243 to see if there is a special way to mute it.   Have a feeling only the potentiometer version can do this.