It costs £8 plus postage direct from Itead.

This is similar to an Infrared device I reviewed a few years ago.

It's a cute little box, small and light enough to hide away anywhere. Even under use, it doesn't get hot.

Note - it only connects to 2.4GHz WiFi. That's standard for these cheap gadgets.

Powered by the ubiquitous micro-USB, it comes with a short cable, but no plug socket. I assume you have plenty at home.

Blinken lights! Little status LEDs so you know what's going on.

Software

You need to use the eWeLink app. Like lots of smarthome apps from China, it isn't the prettiest - but it works. The translations on the app and the user guide would benefit from a more professional approach, but it is adequate.

The app is quick to respond - but I found that it would occasionally log me out, and I'd have to re-enter my password to continue.

It also supports Amazon Alexa! Incredible for a device this cheap. As I mentioned in my previous review, setting up the eWeLink Alexa skill is a bit cumbersome - but it works!

Buttons!

You also get a keyfob with four buttons on it.

It is an RF remote which you can pair with the box. Kinda neat if you don't want to unlock your phone to activate something.

Usage

It works - but there's a catch - how many 433MHz devices do you have? I had to dig out some old demo kit in order to play with this gadget. If you've got compatible devices, this is a useful gizmo - but most modern devices have WiFi built in, so it may be worth upgrading older devices if you can.

If you have devices which need 433MHz controls, this is a ridiculously cheap way to add them to your home network. The Alexa control is the icing on the cake.

Teardown

It isn't a review if you don't get to see the guts :-)

The retail model I've got has populated debug headers and an internal on/off switch.

Nice and neat design. I'm told that it should be fairly easy to flash and dump the firmware. For those who care about such things, the main chip is the ESP8285.

Get It

• You can find out more information on Sonoff's website
• Full specification - including schematic - is on the Itead Wiki
• Finally, you can buy it for £8 (US$10) from Itead directly

Here's a video of me controlling them from my Amazon Alexa:

The latency seems a little slow - hard to tell if that's Amazon only relying on US data centres for Alexa skills, or the connection to my home. Once set up, it works well. Oh... but the set up experience...

Set Up

I'll be honest - configuring a smarthome for voice control is still a pain in the arse. This is mostly Amazon's fault - but it doesn't help that all the kit I use has non-standard interfaces.

Here's the long journey I took to install the skill, configure it, and finally use it.

1. Read the eWeLink tutorial on setting up Alexa.
2. I'll assume you've already set up your Alexa, connected it to the WiFi, and configured the app.
3. In the Amazon app, go to Settings.
4. Select Skills
5. Search for eWeLink (not Sonoff!)
6. Select "eWeLink Smart Home Fan".The "fan" refers to the fact that this is not an official app, not that it only controls fans.
7. Enable the skill.
8. This takes you to the web browser which then redirects to the "coolkit" site.Usually I would tell you to be wary of putting your password into a random site - but this is, apparently, the same company as eWeLink and Sonoff. Confusing, isn't it?
9. Log in with your email address and password and you're eventually redirected back to Amazon
10. Close the browser and return to the Alexa app.
11. Ignore the fact that it is still asking you to enable the skill, exit this page and go back to the home screen of the app.
12. Go to menu, Smart Home. Then click on the Smart Home Skills.
13. Click on the EweLink skill.
14. That just gives you reviews. Because Amazon don't bother with usability testing their apps.
15. Go back and click on the icon for eWeLink.
16. Now "Manage Devices in Smart Home".
17. Oh, we're back here again! Select "Devices"
18. Scroll all the way to the bottom and select "Discover".
19. Wait. And marvel at how crap Philips Hue must be to need extra support text.
20. Hopefully the new eWeLink devices will be displayed.
21. You can exit the app and use voice control.

Bloody hell! No normal person is going to bother going through that many steps, are they?

Oh, and that's not even the worst part! When I first set up the lamp, it wouldn't work. Why? Because I already had an Alexa group called "lamp". There's no feedback in the app - and it's impossible to rename device in Alexa. The Echo just pathetically says that there's a problem - but not how to solve it. So you have to delete the devices, rename them in the eWeLink app, then re-add them.

Alexa is a UX disaster. If you deviate a millimetre from the happy path, you'll be lost in the woods without hope.

This is not the future.

Kit used in this demo

• Sonoff POW review - buy it.
• Sonoff S20 WiFi plug - buy it
• WisQo smart lightswitches - buy them