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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think some guy on YouTube tells how to compensate for it but I need to look again. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> TriEmbed [mailto:triembed-bounces@triembed.org] <b>On Behalf Of </b>Mark Sidell<br><b>Sent:</b> Wednesday, January 14, 2015 10:35 PM<br><b>To:</b> Triangle Embedded Devices<br><b>Subject:</b> Re: [TriEmbed] TriEmbed Digest, Vol 20, Issue 11<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>If I'm not mistaken, the Arduino circuit described measures apparent power, not true power, because it simply averages the current and doesn't take into account the voltage to current phase shift caused by inductive loads. Good enough to tell if your water heater is on, but it may not match what your electric meter says.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On Wed, Jan 14, 2015 at 9:49 PM, Martin Brooke <<a href="mailto:martin.brooke@duke.edu" target="_blank">martin.brooke@duke.edu</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I used an audio jack breakout on an arduino proto shield with a simple RC circuit to level shift the AC.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>here is a <a href="https://drive.google.com/file/d/0B0lP-6BNGel_a09EbFBkeDJWamc/view?usp=sharing" target="_blank">photo</a>. The proto shield is this one from <a href="http://smile.amazon.com/SainSmart-Prototyping-Prototype-Breadboard-Arduino/dp/B0079WI2MK/ref=sr_1_4?ie=UTF8&qid=1421289842&sr=8-4&keywords=Prototype+Shield" target="_blank">sain smart </a> although there are many alternatives for this.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>The break out was from <a href="https://www.sparkfun.com/products/10588" target="_blank">sparkfun</a> for which you need some <a href="https://www.sparkfun.com/products/116" target="_blank">headers </a>and the <a href="https://www.sparkfun.com/products/8032" target="_blank">jack</a> maybe you can find one assembled <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>There is also two resistors and a capacitor needed to get the AC signal into the ADCs input range.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I really just copied the circuit from this <a href="http://www.instructables.com/id/Yun-based-Electricity-Monitor-with-Cloud-Support-T/?ALLSTEPS" target="_blank">intructable</a>. <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>The instructable goes way further, using an Arduino Yun to make it readable via wifi, very cool, but maybe beyond what you want or need.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Cheers,<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><br>_______________________________________________<br>Triangle, NC Embedded Computing mailing list<br><a href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br><a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>TriEmbed web site: <a href="http://TriEmbed.org" target="_blank">http://TriEmbed.org</a><o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>