Help - Components Required ( Air Solenoid )

Hi, I’m just wondering if anybody could help me resource components for the following project idea. I’m from the UK so UK providers would be preferred so I can get the items in a timely manner. eBay is no problem.

Basically what I’m aiming for is to be able to use an Air Compressor, which will connect to a 2 way Solenoid (If possible?) that will allow air to pass through to the required object (I.E Inner tube) but then also be able to release air from the inner tube. I’d assume that there would be a T-Piece on the connection to the inner tube. 1 Solenoid would be on to allow air to go into the tube, and the other would be closed to stop air escaping. Then reversal to deflate. I’m not too sure if this is possible with one Solenoid?

Funny looking diagram below
—> Air Flow In —>
Air Compressor —> Solenoid – { } —> Inner Tube
<— Air Flow Out <—

Ideally, I’d like to be able to check the pressure currently in the inner tube also (Research tells me that possibly an MPX5500 would do the trick?)

Also, what could I use to power the Solenoid (12V adapter) and which transistor would I need to turn the Solenoid on/off

Thanks for taking the time to read this, and look forward to the replies!

xerof: Basically what I'm aiming for is to be able to use an Air Compressor, which will connect to a 2 way Solenoid (If possible?) that will allow air to pass through to the required object (I.E Inner tube) but then also be able to release air from the inner tube. I'd assume that there would be a T-Piece on the connection to the inner tube. 1 Solenoid would be on to allow air to go into the tube, and the other would be closed to stop air escaping. Then reversal to deflate. I'm not too sure if this is possible with one Solenoid?

Standard solenoid valves are one way and rely on the pressure difference to operate, they mechanically amplify using the pressure. You probably need two separate valves.

There may be a single valve solution but its likely to be harder to source and require more actuating power.

For a 12V solenoid a logic level MOSFET and a freewheel diode are probably the way to go.

http://www.amazon.com/250mA-Position-Pneumatic-Electromagnetic-Solenoid/dp/B00A15FUU4/ref=pd_sim_sbs_hi_3?ie=UTF8&refRID=0465TSQNZRS4CAGS61NA

Your inner tube would connect to port A, the pressure line from the air compressor is port P, and the exhaust line is port R. When the valve is not energized port P is blocked and there is a path between A and R. When the valve is energized there is a path between P and A and then R is blocked. This is a "pilot activated" valve meaning that it needs a minimum pressure to operate (~20 PSI). If your pressures are lower (to zero pressure) then you need a "direct acting" valve; for the AirTAC brand that would be a "3V1" model valve.

This tutorial might be useful to you as it describes what those symbols on the side of the valve mean:

http://www.clippard.com/downloads/PDF_Documents/Application_and_Training/Clippard%20Schematic%20symbols.pdf