[Chris] has been playing with the Amazon Echo. It’s sort of like having Siri or Google Now available as part of your home, but with built-in support for certain other home automation appliances like those from Belkin WeMo and Philips. The problem was [Chris] didn’t want to be limited to only those brands. He had other home automation gear that he felt should work with Amazon Echo, but didn’t. That’s when he came up with the clever idea to just emulate one of the supported platforms.
The WeMo devices use UPnP to perform certain functions over the network. [Chris] wanted to see how these communications actually worked, so he fired up his laptop and put his WiFi adapter into monitor mode. Then he used Wireshark to start collecting packets. He found that the device detection function starts out with the Echo searching for WeMo devices using UPnP. The device then responds to the Echo with the device’s URL using HTTP over UDP. The Echo then requests the device’s description using that HTTP URL. The description is then returned as an HTTP response.
The actual “on/off” functionality of the WeMo devices is simpler since the Echo already knows about the device. The Echo simply connects to the WeMo over the HTTP interface and issues a “SetBinaryState” command. The WeMo then obliges and returns a confirmation via HTTP.
[Steve] was able to use this information to set up his own WeMo “virtual cloud”. Each virtual device would have its own IP address. They would also need to have a listener for UDP broadcasts as well as an HTTP listener running on the WeMo port 49153. Each virtual device would also need to be able to respond to the UPnP discovery requests and the “on/off” commands.
[Chris] used a Linux server, creating a new virtual Ethernet interface for each virtual WeMo switch. A single Python script runs the WeMo emulation, listening for the UPnP broadcast and sending a different response for each virtual device. Part of the response includes the device’s “friendly name”, which is what the Echo listens for when the user says voice commands. Since the virtual WeMo devices are free, this allows [Chris] to make multiple phrases for each device. So rather than be limited to “television”, he can also make a separate device for “TV” that performs the same function. [Chris] is also no longer limited to only specific brands of home automation gear.
There’s still a long way to go in hacking this device. There’s a lot of hardware under the hood to work with. Has anyone else gotten their hands (and bench tools) on one of these?
The first step was to crack open the case and locate the serial port. [WarriorRocker] soldered a small three pin header to the pads to make it easier to work on his device as needed. He then connected the Kindle to his PC using a small serial to USB adapter. Pulling up the command prompt was as simple as running Putty and connecting to the correct COM port. If the wires are hooked up correctly, then it just takes a press of the enter key to pull up the login prompt.
The device is little more than the internet and a speaker stuffed into a minimal black cylinder the size of a vase, oh- and six far-field microphones aimed in each direction which listen to every word you say… always. As you’d expect, Echo only processes what you say after you call it to attention by speaking its given name. If you happen to be too far away for the directional microphones to hear, you can alternatively seek assistance from the Echo app on another device. Not bad for the freakishly low price Amazons asking, which is $100 for Prime subscribers. Even if you’re salivating over the idea of this chatting obelisk, or intrigued enough to buy one just to check it out (and pop its little seams), they’re only available to purchase through invite at the moment… the likes of which are said to go out in a few weeks.
