Remember this ? ----- Original Message ----- From: "Marcel Birthelmer" To: "Microcontroller discussion list - Public." Sent: Sunday, August 21, 2005 1:08 PM Subject: [EE]: appliance current sensor Hello all; random project time. This is the situation: of the three people I'm sharing a house with, I'm the only one whose room is not adjoined to the garage. This means that I can never hear when the washer or dryer are done, and so my laundry scheduling is always suboptimal. Now of course I could just set my watch or whatever, but where's the fun in that. One additional criterium that will come in is that these are not my appliances, so I can't open them. Now, I was thinking that it should be possible to pick up the current draw of those appliances and then, via a small embedded system or maybe an old computer, forward this information to the local network or something ----- Original Message ----- From: "Jinx" To: "Microcontroller discussion list - Public." Sent: Sunday, August 21, 2005 3:25 PM Subject: Re: [EE] appliance current sensor > > If a high-permeability core goes around both conductors, then > > the fields cancel out pretty well > I just tried a UGN3503 on our washing machine lead and had > no problem picking up a distinctive 30mV 50Hz signal when the > sensor is over the active and the machine is turned on. There is > negligible signal when the machine is turned off. Enough of a > difference to detect, even unamplified, with a PIC comparator > or ADC -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist