Electronic flow control valves

[chris2012]

Has anyone ever looked into valves which would let you adjust the rate of flow electronically, per chance?
I'm guessing they're not going to come cheap though?

[Fil]

Hi Chris. just chewing the fat, Im not qualified in any sense to offer electric or electronics advice beyond the few simple circuits ive copied of the web, and from some clever bods in here and other brew forums..

However..

you can get 'motorised ball valves' they come in a few flavours, one set need a direct(constant) current during switching between the on and off positions which takes a few seconds.. imho, it may be feasible?? with such valves to apply micro second bursts of juice using something like an arduino to control thus opening and closing a degree at a time. set a ? 200 millisecond voltage output on one pin to respond to a button press?? U will probably need a small SSR rather than a mechanical relay tho..
SS 1/2" moterised ball valves are on ebay china.. Bobsbeer is using em in his all singin and dancing brewtroller setup, tho iirc he is using valves that need a single pulse to signal opening and closing??