Tag Archives: node-red


Your laundry is done

Have you ever forgotten your wet clothing inside the washer for a whole day? I have. Even for two days. They smell. You have to wash them again and you know you might end up forgetting about them again!

Actually that is happening to me since me moved to an old house in a town north of Barcelona. Instead of having the washer in the kitchen, like we used to, now we have it in the cellar, in a place I don’t normally pass by to notice the laundry is done.

So I started thinking about monitoring the washer to get notifications when the laundry is done. And since I was at the same time playing with ITead’s Sonoffs, which has an AC/DC transformer and a powerful controller with wifi, it looked like a nice project to put together.

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S20 Smart Switch

S20 Smart Socket

Since I discovered the Sonoff I’ve been thinking about embedding it inside a switch. I started looking for old power meters, timers,… I had at home but the Sonoff is a bit too long. Why didn’t they design a square board? I event bought a bulky Kemo STG15 case with socket.

Next I decided to design my own board. It is meant to be the “official” hardware for the ESPurna project so it’s called ESPurna too. It’s opensource hardware and available at the ESPurna project repository at Bitbucket. I have some boards already for the first iteration (version 0.1). They are mostly OK but I’m already working on a revision.

But then ITead’s released their S20 Smart Socket. It’s the Sonoff in a wall socket enclosure. Almost 100% what I wanted. And at 11.70€ it’s hard to beat. There are other wifi smart sockets available, mainly Orvibo and BroadLink (an SP2 Centros should be arriving home anyday now) but ITead’s is cheaper and you can easily re-flash it. Just solder a 4 pins header, connect it to your FTDI programmer, hold the S20 button, connect the programmer to your computer and flash. Done.

OK, not so fast. Why would I do that? Why would I change the stock firmware?

The answer for me is a mixed up of philosophy and practicity. But you are right. Let’s go step by step.

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Adding RF to a non-RF ITEAD Sonoff

Yes, sure! You can buy a Sonoff RF and you are good to go, I guess. But I didn’t and I was not so sure about the no-named RF receiver so I ended thinking about adding my own.

But first things first. The Sonoff is an ESP8266 based smart switch by ITEAD which comes with a custom firmware that communicates with the manufacturer cloud to provide “smart” capabilities like remote switching or scheduling. The cool thing is that it has a line of pins that expose the VCC, GND, RX and TX pins of the ESP8266 and a buttons attached to GPIO0 so very soon it got hacked and there are a number of firmwares already available. I’m not an early adopter and some work has been done and reported by Peter Scargill, Javier or even in instructables.

The ITead Sonoff Smart WiFi Switch after a small hack to use the Avidsen RF remote to toggle it

The ITead Sonoff Smart WiFi Switch after a small hack to use the Avidsen RF remote to toggle it

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