The quarterly bill tumbled through the letter plate. Normally I just leave in the heap of unopened mail nearby but I decided to open it. Quarterly electricity bill – £430!! After uttering some choice expletives at high volume, I decided something needed to be done. A hour or two on a few money saving websites (mostly moneysavingexpert.com), I found a better tarrif, and more interestingly for the geek inside, a tarrif that included a free currentcost envi energy meter! These normally retail at about £45 and consist of two units 1) a current clamp which you clip around the cable going into your fuse box and 2) a receiving unit that can be placed within 100ft (it’s wireless). It displays current watt usage, local temperature. More importantly it has a serial port on the back which spits out XML data every 6 seconds.
A serial port to usb adapter is available from the manufacturers for about £10, but a quick trip to google revealed that many mobile phones shipped with a USB cable that was in fact a USB – serial converter. I never throw anything away – to my wife it’s my deepest character flaw. Needless to say a quick rummage in my man drawer yielded 6 mobile phone USB cables. A win for the man drawer! (If the portuguese escudos ever gets reintroduced, I’m quids in by the way). Plugging them into the laptop and checking dmesg showed that 2 were indeed usb-serial cables. 10 mins with a soldering iron and an rj45 plug, I had a rather ugly, but free, usb-currentcost adapter. It’s now plugged into my revo running ubuntu 10.04. Continue reading OMG! The electricity bill!
