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Good evening Brian,<br>
<br>
I think you'll find an H-Bridge to be the best solution from an
availability standpoint (used to drive stepper motors and DC
brushed/brushless motors), the inherent lockout design (keeps you
from shorting your supply bus), and the isolation necessary between
your 12 volt power supply and your controller circuitry. Oh, did I
mention the good H-Bridges limit current?<br>
<br>
Simple to implement, one I/O line to turn on, second I/O line to
turn off.<br>
<br>
Not sure if anyone has made an H-Bridge interface board specifically
for the Raspberry PI ... but I've seen H-Bridge boards for arduino
at Radio Shack, as well as the usual internet sources. Solder a
couple of I/O lines and a ground, and you are in business. Hot glue
makes wonderful mounting hardware, by the way.<br>
<br>
You can build your own H-Bridge if you need more current, just
include an interlock circuit that pulls the opposite bridge device
inputs to ground when you enable ... add some time delay to keep
from blowing transistors off the board (no, you may NOT ask me how I
know about this!). :)<br>
<br>
Hope this helps.<br>
<br>
Regards,<br>
<br>
Rick<br>
<br>
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<div class="gmail_quote">On Fri, Dec 4, 2015 at 12:51 PM,
Grawburg via TriEmbed <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:triembed@triembed.org" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:triembed@triembed.org">triembed@triembed.org</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">I have a quarter-turn
ball valve with a 12V actuator [HSH-Flo 1/2" DN15 12VDC
CR-05 FNPT SS304 Position Feedback Motorized Electric Ball
Valve.] I'm using opto-isolated relay activated by a
Raspberry Pi but can only control one direction because
the valve reverses direction by flipping the leads. If I
was doing it mechanically I would have a double pole
triple throw rotary switch. I cannot find a suitable
opto-isolated relay that is 2P3T...at least one that
doesn't cost a fortune. Any suggestions to help me think
this through would be welcomed.<br>
<br>
<br>
Thanks,<br>
Brian Grawburg<br>
<br>
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