Basic Circuit Design Help

[mrmagoo]

Very big electronics newb here.  I can solder, wire things up, etc, but the most complicated circuit i ever put together was a blinking LED using a 555, led and resister  .  My projects usually side on the mechanical side of the fence (lathing, milling, etc), although i did rewire a whole car once, but thats getting off topic.

So im in the middle of a project that requires me to deliver a small, controlled amount of compressed air at the push of a pushbutton.  I am planning on using https://www.alibaba.com/product-detail/3-5mm-Flow-Bore-2V035-06_60748410126.html?spm=a2700.galleryofferlist.0.0.3aeb35c1LxatxG, which is a simple solenoid valve that opens when 12v is applied (easy).  Power source will be normal batteries in series to get 12vDC.  But I need it to only open once per push of the button.  To open the valve again, the user must release the push button completely and press it again.  And I need to be able to dial in how long the valve stays open per button push.  Doesn't have to be digital or anything fancy, tuning a Pot would be good enough.

Everything i know how to do (which is very limited (basically a 555, a potentiometer and a transistor) would cause it to pulse on/off/on/off or just stay open when the button is pressed (direct wire to the push button).

I dont expect a full blueprint (although that would be absolutely fantastic  ), but just some help getting on the right track would be amazing.  What components would I even need to do this?

[xavier60]

Are you using a bread-board to experiment on?
See if you can get this example to work, although it doesn't quite do the correct job.
 https://www.petervis.com/GCSE_Design_and_Technology_Electronic_Products/falling-edge-triggered-monostable/falling-edge-triggered-monostable.html

[xavier60]

This should be closer to what's needed.
Most of the component values have been picked out of a hat and aren't critical.
For example the 10k resistors could be anything from 4.7k to 100k without causing problems.
C1 ,R2 and R3 affect the timing adjustment range.
The rail bypass, C3 an be just about anything upto 1000uF.
A MOSFET would be a better choice for Q1 depending on what you have.
I bought a heap of IRF44Z MOSFETs years ago so I'd use that although it's total overkill.

Edit: The circuit draws some idle current so might not be suitable for being battery powered.

[mrmagoo]

Thanks for the time/effort. I will give it a try 

A breadboard is not a bad idea for setting up a prototype/experimenting.  I will pick one up.