Arduino Arsing About

Today I looked at connecting the CT - Current Transformer? This is a 2000 turn secondary, clipped around the 1 turn of the incoming house mains cable. It thus provides a maximum RMS current of 20mA, given a maximum house current of 100A. This is measured using a load resistor with a value that makes the voltage drop across it match the input range of the Analog pins of the Arduino. This is all discussed on the OEM website . I'm using the Arduino at 3.3V, so the "burden" resistor value is  R = V/I where V = AREF/2 (AREF is Arduino Reference) I = PeakSecCurrent => R = (AREF/2)/PeakSecCurrent Substituting  PeakSecCurrent = PeakPriCurrent/Turns => R = (AREF/2)/(PeakPriCurrent/Turns) Substituting PeakPriCurrent = (RMSPriCurrent * SQRT(2)) => R = (AREF/2)/((RMSPriCurrent*SQRT(2))/Turns) Substituting AREF = 3.3 RMSPriCurrent = 100 SQRT(2) = 1.414 Turns = 2000 (3.3/2)/((100*1.414)/2000) = 23.34 Ohms  Closest  I can get to this value is by pairing some resistors in p...

openenergymonitor.org is about "Open source monitoring for understanding energy", and the  efforts  of some stalwarts who have designed, constructed and had manufactured a  number  of  monitoring devices and supporting  software. These are currently based on Raspberry Pi and the Atmel chip used in the Arduino UNO , along with 433MHz radio comms and lots of open source software. The designs are comely open source, to the extent that you could build your own if you were prepared to have SMT PCBs made and so on.  I am interested in monitoring our energy consumption on a more fine grained basis than the 30 minute intervals that BG, in their wisdom, allow limited access to on their website, based on our "Smart" meter (as a SMETS1 device, not smart at all in fact). So the emonPi , with its RPi and an Arduino-stack based monitoring "hat", as a single box device that supports current, voltage, meter pulse sensing a...

 Another in the occasional series of domestic equipment repair stories! We replaced our condemned (no, really, the dishwasher repair man came, saw our hob, and said “You really should not use that again, it’s really dangerous!”) hob in 2015, with an AEG HK654200FB PNC 949 595 108 01. It’s a pretty standard effort, and like all home gear, is made of the same parts as every other one of the Electrolux brands. We love it, it’s really fast, really clean, highly controllable and many a fine meal has been cooked on it.  AEG HK654200FB Induction Hob The product label Sadly (to borrow the word of the last two years) half of it died last week. The right hand pair of cook areas don’t heat up, there’s a repeatedly clicking relay, all the controls work, but no heating action. The left hand side fortunately is fine. Off to the AEG support website, looking for parts, if only to see what kind of thing might be wrong with it, and get some idea how much it might cost to fix. The original came ...