The first thing I did was to trim the leads on the SS49E sensors and spread them out a bit for easier access.
Then I wired the power connections to all the sensors and the buttons. Obviously a lot of care was taken not to introduce shorts, especially with the tiny hall effect sensors. The perfectionist in me cringes a bit looking at this, but I am determined to keep the BOM down so point-to-point wiring it is.
Next I wired the outputs of the 16 sensors and power to the multiplexer (left below). Finally I connected the pro Micro (right below) to the buttons, multiplexer, and project power.
Here are all the connections.
|Arduino pro Micro||CD4067BE Multiplexer||Wire Color||Other|
|VCC||+5V||Dark Orange||Also powers the sensors.|
|A0||Common Input (Read the channel selected by S0-S3)||White|
|I/O Pin 2-9||Light Orange||Button 1-8|
|I/O Pin 15||S0 (These four outputs select which of the 16 analog channels to read.)||Yellow|
|I/O Pin 14||S1||Yellow|
|I/O Pin 16||S2||Yellow|
|I/O Pin 10||S3||Yellow|
|I0 - I15||Green||Sensors 1-16|
|GND||E (This is an inverted chip select pin.)||Black|
I wrote a quick and dirty test program and discovered a couple of bad solder joints, but everything seems to be working as expected now. Software time.