I'm looking to build a relatively cheap and simple electrical device to do the following:

- It needs to stop water flow (say through a small flexible tygon tube) given a 5V DC power source.
- it needs to be able to allow water to flow again either by deenergizing or by reversing power or whatever.

Aside from utilizing a small DC motor in a clever fashion, how else could I accomplish this? Any suggestions will be greatly appreciated. Thank you.

9/16/2005 9:12:52 PM

dc motor + faucet

[Edited on September 16, 2005 at 9:28 PM. Reason : a guy on here used a MCU to accurately dispense water from his kitchen sink a while back. profess0r?]

9/16/2005 9:27:40 PM

instead of using a regular DC motor, use a brushless DC motor (aka induction motor with D-Q PWM control )

9/16/2005 9:29:40 PM

they make solenoid valves that operate on low voltage or high. plus you could use a relay to use whatever voltage you need.

9/16/2005 9:37:11 PM

you need a DC normally closed solenoid valve
this one is 24VDC but you could probably find one that is 5V or use a relay like ^ said
http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=3429166&PMT4NO=0

9/16/2005 9:48:32 PM

Thanks for all your wonderful advice. And thank you Halo for that link. I'm checking that out right now.

9/16/2005 9:56:37 PM

btw: that is going to require some pressure behind it in order to work.

9/16/2005 11:08:22 PM

I understand that some valves require some backpressure in order to open but I don't see anywhere that this one does. I'm looking over the spec sheet and the manufacturer's website and can't find anything about it. I'll call one of their tech support tomorrow and ask.
Thanks again for the link. I found a 12Vdc model that's only $25 and hopefully it'll work out nicely.

9/18/2005 4:34:00 PM

here is one that is 24vac for $4.50.

http://www.allelectronics.com/cgi-bin/category.cgi?category=search&item=SV-2&type=store

Not sure what you are doing but if you need a water pump the same site has a small one for 8.50

http://www.allelectronics.com/cgi-bin/category.cgi?category=search&item=PMP-4&type=store

9/18/2005 8:39:10 PM

Oh I appreciate that Matt... and good suggestions. Unfortunately I'm building a solar-powered device so I'm afraid I can't use AC devices. I already placed the order for the 12V solenoid valve and I even spoke to one of the company's engineers and he told me it would work fine for my application. Thanks again.

9/19/2005 8:38:04 PM