2022.08.25
- thinking about upgrading one side of the CSM84 to CL series feeders, which
  operate pneumatically with a valve per lane that needs a FET switch to 
  activate.  We have 42 mechanical 8mm feeder spaces per side, I'd hope to
  end up with support for 42 CL feeders, all likely to be used exclusively
  for 8x2mm 0402 lanes.

- imagine a board with a 64-pin STM32L151 driving 21 dual FETs to operate
  42 lanes.  processor powered by the USB interface that would be used to
  interface with the board.  2-pin connector like the ones used on my USB
  audio boards to bring in DC power for the valves.  low-side FET switches.

- if we posit 2 50 pin headers, putting one on each end of a board and
  assuming we'd mount the board in the center of the side with 2 pins of
  each ribbon cable connecting to a valve seems to make sense?

2023.01.13
- talking to keithp, using STP for the valve control wires feels like a better
  plan, so let's use stacked pairs of 15-pin D shells, 10 connectors total.

2023.01.23
- ordered a 500' spool of Belden 9451 for valve actuator cabling
- the 2-pin DC in connector used in the design is a TE 284512-2, which mates
  with the 2-screw, on-cable connector 284506-2.  I have in stock some 4ucon
  parts that are essentially identical, 19835 is the on-board part and 19840
  for the on-cable part.