Do you need to know when it gets unplugged vs when it is turned off? For instance a lamp may draw no power but still be plugged in. If so, a mechanical solution may be your best bet. -Adam On 5/10/07, alan smith wrote: > Well, I've been trying to solve a particular problem for a few months, sorta on again, off again issues. > > Simply put, I need to know when something has been unplugged from a AC socket. I don't care about how much current its drawing (I do...but I dont need to know), because in some cases it might be a 100mA wall wart and in other cases a 100W power supply. I just want to know....did it get unplugged. > > I've looked at some exotic solutions like power monitor chips but they aren't really designed for this. I've played with Allegro hall sensors but the sit at 2.5V nominal, and just mimic the AC waveform and yes, with a larger load I can see it but smaller devices do not make a large enoough effect even when I use a simple gain stage op-amp. > > Nothing really gives a solution to cover all the ranges. I need it small, cheap and simple to build. (think production enviroment). > > > So, any good ideas out there? > > > --------------------------------- > Get your own web address. > Have a HUGE year through Yahoo! Small Business. > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Moving in southeast Michigan? Buy my house: http://ubasics.com/house/ Interested in electronics? Check out the projects at http://ubasics.com Building your own house? Check out http://ubasics.com/home/ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist