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<div class="moz-cite-prefix">I think we should look at this circuit
again. The intent is for (*output*) pin "IN0" to be pulled to
ground to allow current to flow through the optoisolator and the
LED, coupling light into the phototransister to turn on Q1 and
pull in the relay (which presumably supplies current to the
solenoid). When the pin is driven high the current flow stops and
the output pin is looking into the high resistance of the LED. <br>
<br>
But this is annoyingly complex, and now you need a third power
supply voltage. <br>
<br>
Instead I think one MOSFET and one rectifier will get the job
done. Here's an example of a MOSFET driving a solenoid. The MOSFET
Adafruit sells has a max on threshold of 2.5 volts, so a Raspberry
Pi gate should turn it on just fine.<br>
<br>
<a class="moz-txt-link-freetext" href="http://learn.adafruit.com/biometric-security-box">http://learn.adafruit.com/biometric-security-box</a><br>
(solenoid circuit at
<a class="moz-txt-link-freetext" href="http://learn.adafruit.com/biometric-security-box/circuitry">http://learn.adafruit.com/biometric-security-box/circuitry</a> )<br>
<br>
-Pete<br>
<br>
<br>
<img src="cid:part1.02040505.08060603@soper.us" alt=""><br>
<br>
On 11/3/2013 5:10 PM, Scott Hall wrote:<br>
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<blockquote cite="mid:5276C9CE.8040909@gmail.com" type="cite">
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<div class="moz-cite-prefix">Excellent catch for newby. It is by
no means the only way to approach the problem, but a very
effective one.<br>
<br>
The 2mA draw of the LED in the optoisolator is well within the
GPIO pin specs of the Raspberry Pi.<br>
<br>
However make sure that you use a separate 5V supply to power the
relay board, but you can power the opto- LED from the R'Pi's
3.3V power if you use a 470ohm resister (R1) instead and forgo
the extra LED (IN1), or use a 120ohm resister if you keep the
extra LED.<br>
<br>
On 11/03/2013 08:53 AM, Lucas Rumney wrote:<br>
</div>
<blockquote
cite="mid:CACCReNJv7M6znD9=H_fz72dirc01vwXnEO3KLxdUYJW5BFBPRQ@mail.gmail.com"
type="cite">
<div dir="ltr">I am sorry to email the group yet again for the
same project, but I have been doing research and I wanted to
know if there would be any issues with using these parts
together, and if they could be put together into a circuit
that would actually protect the pi, and control the solenoid
with the pi (I am a real noob at this, but I don't intend to
be for long)?<br>
<br>
<br>
<div>would this optoisolated relay board cover all of the
parts I need, and be in the correct range (safe fore the
raspberry pi, and also usable with the solenoid linked later
in the email?)<br>
<a moz-do-not-send="true"
href="http://yourduino.com/sunshop2/index.php?l=product_detail&p=218">http://yourduino.com/sunshop2/index.php?l=product_detail&p=218</a></div>
<div><br>
</div>
<div>solenoid: <br>
<a moz-do-not-send="true"
href="http://www.adafruit.com/products/413#Technical_Details">http://www.adafruit.com/products/413#Technical_Details</a><br>
<br>
I have read up on the relay board, but I don't understand
all of the stats, and I dont want an imcompatability to ruin
my pi. </div>
<div><br>
</div>
<div>Thank you guys for being so helpful, I've been trying to
get this done in between work and school. <br>
<br>
Lucas </div>
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<pre class="moz-signature" cols="80">--
Scott G. Hall
Raleigh, NC, USA
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:ScottGHall1@GMail.Com">ScottGHall1@GMail.Com</a>
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