Hardware requirement question

Hi there everyone, new to the forum and all this Arduino stuff. Not much a fan of chit chat so I'll get right to it.

I've been carrying the idea of using Arduino for something in my life for a while and finally found something to apply it to. My car to be specific.

The thing is I've been pondering the idea of installing a central air distribution system to inflate and deflate the tires on my truck and I really want to not keep it simple and have a controlcenter to set the desired pressure and let something electronic do the work for me. The truck has a modified A/C compressor, a tank and soon the inflate/deflate system wich is more or less a DIY project from start to end. So my question to you who have more experience than me in Arduino boards is how minimal can I go?

It should be able to:

-monitor 2 air pressure sensors
-start the compressor when sensor 1 shows less than X and stop it when it reaches Y
-have a display and a few keys
-be able to control 3 solenoids, 2 for air in and air out and maybe 1 output to block off each tire when setpoint is achived. (Not sure if that will be necessary but keeping the option open)
-display should preferably be able to show tank pressure, current tire pressure and a setpoint

Basicly it should work like those you can see on petrol stations and other service stations around the world. Ask for say 25psi and it reads, pumps, reads, pumps until desired pressure is achived. All 4 tires will be interconnected through a junction block.

I really don't know anything about what these boards and shields are capable of but I am an electrician and a long time tinkerer so the actual wiring and fabrication of things is not an issue and as for the programming I'm not afraid of faceplanting myself into the deep end. Worst case scenario is I'll find someone who speaks computer to help me out. This should install as a unit into the dash and be completely standalone from the rest of the car apart from getting 12v from the battery through a switch.

So any ideas how minimal I can go?

Not a difficult project (electronically) for an expert, but non-trivial for a novice. You'll need:

  • mosfets and flyback diodes to control the solenoids (3 Ardino pins)
  • mosfet or relay to control the compressor (1 Arduino pin)
  • text LCD display, e.g. 16 chars by 2 lines (6 Arduino pins)
  • rotary encoder with internal push button (3 Arduino pins) - I'm suggesting a rotary encoder so that you can easily adjust the setpoint on the LCD display
  • depending on the pressure sensors you use, probably some op amps or instrumentation amps to amplify the outputs so they can be fed to 2 Arduino analog input pins

That's a total of 14 pins, which is well within the capability of an Arduino Uno or Leonardo.