Just an update – today I was clearing out my office boxes and noted 4 old mains control blocks – the kind you buy at B&Q – the kind the cats lose the remote controls – these were a little bigger than some but I think the general principle applies to many of the cheaper units. B&M had some at a great price – 3 for a tenner – the software sadly was rubbish and did not remember the state they were in when the power cycled.
Well, as we know, Sonoffs are small boards – and, well I took one of the mains control units apart, ripped out the electronics – and – the Sonoff board fit in there a TREAT.
Total time around 15 minutes or less and a soldering iron. The mains units had a common neutral (as do the Sonoffs – mains in – mains out. I wasn’t interested in buttons so I took them out – but then I thought it might make sense to leave the holes open to get rid of any heat.
And there you have it – one plug-in-the-wall mains controller… larger than a sonoff but for many applications a hell of a lot more useful than having to solder to a choc-block.
The photos should scale when you click them. In the photo below I connected neutral (Black) to the common just one one side of the sonoff, the mains in to the other input and I used a piece of single choc-block to extend the other red lead.
In the photo above I have the output side of the Sonoff nearest the mains plug – in practice (the next day) I’ve now done four of these and it is better to have the dirty end (blue VDR) nearest the mains plug – black wire into the neutral (which is common so you don’t have to connect the other end) – bottom incoming red wire into live… and the top live wire extended with a single choc block to the output on the other side of the board – no soldering required. As you can see below, here it is looking ok (I put a label on with the MQTT name of the device). After listing to comments in here I have “Maximum 1KW” label – though I think that is under-ambitious – probably 1.5k is possible but I’ve not tested it – they claim 10 amps hence 2.5k but the relay is just too small.
Anyway, under an hour to make 4 of them – not a bad investment of holiday time.