What would simplify things more is a NO / NO transistor toggle. There are two fans per unit. One blowing in ( when HIGH ) and the other blowing out ( when LOW ).
I can do this through programming turning FAN A on, FAN B off to inflate, then FAN B off, FAN A on to deflate.
What would be easier ( I think? ) would be two circuit boards... a NPN and a PNP. Then one pin/signal could control both. If HIGH one fan is on the other is off - if LOW the opposite.
Could also use a DPDT relay but they tend to be rather noisy with all the clicking.
Can find 16 channel NPN boards but not PNP?
Any suggested on when a 16 channel PNP board can be found or alternatives to running these fans?
thanks