https://www.youtube.com/watch?v=3DDNAgJrnj4EM On 2/20/2018 4:12 PM, Neil wrote: > Photodiodes & phototransistors should be much faster than > photoresistors, so cleaner edges. I believe photodiodes have the > fastest transistions so a schmitt trigger may not be needed (other than > the I/P of the microcontroller). > > I like this project idea... would be nice to see how things change as my > 3D printer, fridge, A/C, etc comes on, without having to move around a > plug-in power monitor. > > Cheers, > -Neil. > > > > > > On 2/20/2018 5:34 AM, Clint Jay wrote: >> In all the energy monitor projects I remember seeing I've not seen a CdS >> cell used, not that I think there is anything wrong with that idea, they= 've >> all used a phototransistor or photodiode, I seem to remember one that us= ed >> an LED... >> >> The late John Becker had one or two published in EPE that were Pic based= , >> might be worth seeking those out? >> >> On 20 Feb 2018 10:29, "David C Brown" wrote: >> >>> This is one of those so trivial problems that shouldn't need advice but= , as >>> so often with me, I have over researched to the point where Ic an't mak= e a >>> decision. >>> >>> Since I am not going to get a smart electricity meter real soon now I >>> intend to build my own power monitor. The meter has a red LED which >>> flashes 1000 times per kWh and the key to the project is measuring the = time >>> between flashes. >>> >>> But I can't decide the best way to detect the flashing LED. CDS photo >>> resistor followed by a Schmit trigger; photo transistor followed by a >>> transimpedance amp. There should be no problem excluding ambient ligh= t >>> and the LED flashes for about 1/2 second. >>> __________________________________________ >>> David C Brown >>> 43 Bings Road >>> Whaley Bridge >>> High Peak Phone: 01663 733236 >>> Derbyshire eMail: dcb.home@gmail.com >>> SK23 7ND web: www.bings-knowle.co.uk/dcb >>> >>> >>> >>> >>> *Sent from my etch-a-sketch* >>> -- >>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>> View/change your membership options at >>> http://mailman.mit.edu/mailman/listinfo/piclist >>> --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .