Belkin WeMo Teardown

[Brian Dipert] over at EDN has a teardown of Belkin’s answer to the Internet of Things (IoT) craze: the WeMo. This little WiFi gadget plugs into an outlet and lets you turn a connected device on and off from a smart phone app or something like Amazon Echo.

As you might expect from a cheap piece of consumer hardware, there’s not a whole lot inside. The digital board contains a Ralink WiFi chip, an antenna etched on the PCB, and a handful of components, including an SDRAM and some flash memory.

The Ralink chip is commonly found in wireless access points/routers, and the WeMo uses that capability for configuration. If you’ve ever configured a Google Chromecast, the procedure is similar. The WeMo creates its own WiFi network that you connect to. Then you can configure it to connect to your preferred network.

A second board has the AC interface which uses a good old fashioned relay to switch the live wire of the AC outlet to the load. The neutral and ground wires simply pass through.

We’ve hacked around the WeMo a few times including how to make fake WeMo devices and how to hack into one using the UART. We even found a tutorial on putting OpenWRT on the things. We’re surprised that we haven’t seen more WeMo hacks — are you holding out on us? Let us know in the comments.

If you haven’t run into a WeMo before, you can see a review of how it works for a user in the video below.

30 thoughts on “Belkin WeMo Teardown

    1. And that’s the problem. WeMo was not built to any of the standards and therefore is a fail. Look for Zwave for a standard that is easily hackable, and zigbee if you want a little more difficult to use but still hackable.

      I remember WeMo, I tried them years ago and was not impressed as they kept falling off the wifi.

      1. Z wave is among the WORST systems I have ever had the displeasure of working with. It is an example of what happens when too many computer scientists design a system. I was dumb enough to think that a $2000 SDK would be worth a damn. In the end you get a bunch of poorly documented overly-complicated 8051 embedded c code that requires the keil 8051 compiler (which was not included). Don’t point to Z-wave as a success.

  1. Oddly enough I actually saw a kit for the dratted thing at Micro Center several weeks previously. I freely admit I’m tempted.

    As for configuring a Chromcast, all I did was buy it and install it, and the application on this laptop. The application found the device and promptly configured it. I still can’t find anything interesting to watch on it.

  2. The wemo is a ridiculous size. It blocks every adjacent socket no matter what orientation the sockets are. I’ve bought some wifi sockets off aliexpress – much smaller and don’t block everything beside it from being used. Don’t work with the amazon echo unfortunately and the app is all in chinglish, but work fine.

      1. I have a few of these – – that one is available with a US plug on it if you look around.

        I havent tried them on 110 volts but they all claim to be universal voltage. The smaller round one I got is this.

        Only a chinese plug on them which thankfully is almost the same as a NZ plug so fits most sockets. The black model has an IR emitter array which I use to control my aircons when I am not home.

  3. They should really switch the Neutral line too. In badly-wired houses (and I hear in the USA that’s not rare), sometimes the lines get switched. Everything still works as it should, since cutting the neutral will also stop current flowing. But it means a device can be live when it’s switched off. So the contacts in a lamp can still zap you when you’re changing a bulb, for example.

    It’s not a big thing, but it’s good practice.

    1. This. Is an annoyingly common occurrence even in the UK. Infact perhaps worse in the US as im sure i read somewhere the neutral isnt always at ground potential? or is that for 220v utilities?

      1. There are 5 standard earthing systems in the UK. They all have N & E joined in some way, if you are not on a building site and your N&E are at different potentials, you have a problem :-)

  4. This cheap WiMo is about $50 where I am. That’s anything but cheap for ones single outlet.

    What we need is a protocol (if it doesn’t exist??) that allows the communication to go via the power wires in the walls with some very limited security so you neighbour isn’t turning your fridge off for kicks.

    Then the power outlet hardware could be made as inexpensive as possible. Couple that with a single WiFi to power wire network bridge and you have all the feature of the IoT.

    If I added up $50 for every power outlet (including power boards) in my house then this thing would cost me more than the house is worth!

    1. There was x10 that did that, its from the 70’s and is basically unusable in a modern house where every device has loads of capacitance across the power input to get the interference down.

      wemo is expensive, there are plenty of other options around on aliexpress and ebay that dont have the brand recognition and distribution that belkin have.

      When a complete microcontroller with wifi is available for under $3 in single unit quantities like the esp8266 modules, I dont really see the value if resorting back to power line communication, which will have to have a significant amount of condiditioning and protection components on it.

      Wireless was hard in the past, now it is cheap and easy.

  5. this is pretty old technology: it’s basically a router stuck inside a socket. when this came out you could still replicate the functionality with a cheap router and relay.
    there are many similar products available now. Even when this came out there were a few companies that offered regular radio sockets + internet gateway for way better price(assuming you needed a few of them, not just one).

    I find remote control sockets to be quite limited in functionality…at least from my usage needs. I would rather have the functionality included directly in the product itself.

  6. One big thing that has reduced the utility for x10 and all other remote switching at the plugs is there are so many devices that require constant power to retain time and other settings.

  7. If you have more than one outlet to switch would it not make more sense to have a single TCP/IP gateway and all the outlets talking to it via the power cables as that would be more secure and reliable?

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