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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'>This looks really good, price wise and simplicity. Forgive me for this question, but what does that plug go into to process the signal? Is there another module for this? <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><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks!<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><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dwight<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>Martin Brooke<br><b>Sent:</b> Wednesday, January 14, 2015 4:01 PM<br><b>To:</b> TriEmbed Discussion<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><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I have used <a href="http://www.amazon.com/SCT-013-030-Split-core-Current-Transformer/dp/B005CTWE8A/ref=sr_1_2?ie=UTF8&qid=1421267065&sr=8-2&keywords=AC+Current+Sensor">these</a> low cost current transformers There are more or less sensitive versions this one is 30A, probably good for a water heater.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>There are also open resistor versions that you can customize to get any sensitivity you like. (Or you can open it up and cut out the resistor inside)<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"'>You need to separate the hot AC wire and run it through the transformer. This does mean you will have to strip off the outer cover of the wire and expose the Hot wire.</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>the ADC on arduino can capture a pretty good sine wave of the current flow as follows:</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>#define Arraysize 300</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>#define loopdelay 1</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>int r[Arraysize];</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>unsigned long t[Arraysize];</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>int i;</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>String readingline, timeline;</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>void setup() {</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> // put your setup code here, to run once:</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> Serial.begin(9600);</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>}</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>void loop() {</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> for (i=0; i<Arraysize; i=i+1)</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> {</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> // send the value of analog input 0:</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> r[i] = analogRead(A0);</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> t[i] = micros();</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> }</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> Serial.println("------------------------------------");</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> for (i=0; i<Arraysize; i=i+1)</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> {</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> readingline = "Iread = , ";</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> readingline += r[i];</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> timeline = "time = , ";</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> timeline += t[i];</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> readingline += ", ";</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> readingline += timeline;</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> Serial.println(readingline);</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> }</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>delay(loopdelay);</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>}</span><span style='font-size:10.0pt'><o:p></o:p></span></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Plotting r vs t can give you lots of info about your water heater current.</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>However it may be that the Hall sensor is a much better way to go! No wires need exposing!</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I just ordered a couple they looked so good.</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>Martin</span><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><div><div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></div></div></body></html>