<div dir="ltr"><div><div><div><div>If you are planning to use Official PoE, remember that while the current is limited to 300ma, this is at around 44 VDC, the spec for 'regular' PoE is around 13 Watts of available power at the field end. To operate your R-Pi or other device you need to drop that down to the right supply voltage, so a shield with a DC to DC converter would do nicely.<br><br></div>On the other hand, there are cheap and easy power injector cables that allow you to piggy back a DC supply of your choosing onto the Ethernet cable at the head end and then pull it back off on the field end. $6 at Adafruit for a pair: <a href="https://www.adafruit.com/products/435">https://www.adafruit.com/products/435</a><br></div>and if you don't need a pretty injection molded cable, you can make your own for the cost of the barrel jacks. <br><br></div>Clearly, some thought needs to be put into the cable lengths, DC losses and just how much power you need, but this IS a viable option.<br><br></div>Glen<br><div><div><div><div><div><br><div class="gmail_quote"><div dir="ltr">On Fri, Oct 2, 2015 at 9:06 AM Carl Nobile via TriEmbed <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Pete,<div><br></div><div>I just checked, there are two specs PoE and PoE+. The first one has a maximum current of 300mA and the second one has a max of 600mA. Obviously both are too low. Too bad, this was a good idea.</div><div><br></div><div>~Carl</div><div><br></div></div><div class="gmail_extra"></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Oct 2, 2015 at 8:36 AM, Pete Soper via TriEmbed <span dir="ltr"><<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
WIthout a switching converter on the other end the wrong order of
magnitude of current is available:<br>
<br>
<a href="https://en.wikipedia.org/wiki/Power_over_Ethernet#Power_capacity_limits" target="_blank">https://en.wikipedia.org/wiki/Power_over_Ethernet#Power_capacity_limits</a><span><br>
<br>
<div>On 10/02/2015 07:02 AM, Jim Ray via
TriEmbed wrote:<br>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Has
anyone modified Raspberry Pi to use PoE for power? Using
standard Ethernet to drive a communications sub system based
on another Raspberry Pi that has the requisite i/o and
processor makes a lot of sense to me.</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u><u></u></span></p>
<br>
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</blockquote>
<br></span>
-Pete<br>
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