They are a bit trickier to find.
I tried a cheap plastic based one years ago, reed switch type, and it didn't work well for me, had to be plumbed in vertically and was inconsistent.
You could make a window voltage comparitor and use the pressure switch to turn on a light.
You could have it run a relay and output 12 volts to a bulb when the pressure is within a specified range with the pressure transducer.
If it got under or over pressure you could use a comparitor and output an alarm or warning light as well.
Overpressure would be over the maximum you normally use or can use, signalling a plugged nozzle or two. |