I started with the idea of a hammer valve, bought some parts, looked around my workspace to find some usable things and finally came up with this...
... a neat little push button pilot valve.

These are the parts.

From left to right:
1/2" to 1/4" reducer
1/4" nipple
1/4" connector
1/4" end cap (drilled hole in the middle)
little spring
adjusting knob of an old mechanical alarm clock
The little aluminium rod is a spacer (something that you find between a motherboard and the chassis, only longer).