Controling power outlets via Bluetooth | Hacker News Reader

Controling power outlets via Bluetooth

kickstarter.com

24 pointsaeolus4220 comments

I don't quite see why they want to make this.

Remote controllable power outlets have existed for a very long time. At this point, you have dozens of options, and several home automation industry standards that allow all these options to interconnect with each other. You can combine plugs, light switches, motion sensors, keypads, door openers, thermostats and virtually everything else in your house with any brand's Zigbee or Z-wave hub, or directly from a PC/app over wifi.

Z-wave/Zigbee are already low-power mesh networks. I don't think there's any advantage to re-implementing that over Bluetooth with a different protocol, while the disadvantages if you ever want to do more cool home automation stuff than just power plugs are many.

If for some reason this all sounds scary and you'd prefer just plugging something into the wall and using an app, that's been on the market for years too. The easiest way to get started is to walk into your nearest Best Buy or Home Depot and pick up a Belkin Wemo switch. It plugs into any outlet just like this Kickstarter but connects to your wifi network instead of BT. There's an Android app to control the plugs (from inside the house or over the internet), but they also speak UPnP so are easy to integrate into your own software.

I believe they went with bluetooth because all smartphones have it, it doesn't require a special base station and can send simple serial commands fairly easily from an iOS app.

Honestly though, I prefer wi-fi over bluetooth because I can connect to an entire network of smart devices. Bluetooth would limit me to one device at a time.

This claims to create a mesh network. If that's done well, you should be able to talk to all devices at once, even outside of regular Bluetooth range.

Bluetooth has the advantage of being supported by most computers and smartphones already, with no additional hardware.

Zigbee has the problem that its specification's license is incompatible with the GPL, meaning that the Linux Kernel will likely never have full support for it, and thus neither will Android[1]. Given that Bluetooth is already ubiquitous on computers and smartphones, and Bluetooth LE is starting to catch on, it's pretty likely that Bluetooth could supplant Zigbee in not too long if a few hardware vendors started selling Bluetooth controlled hardware rather than Zigbee.

So yes, you can get a Zigbee hub and use Zigbee via a hub, or you can use something that connects via WiFi. Zigbee has the disadvantage that you need a separate hub. WiFi is quite complex (and thus more expensive) and doesn't work well for low-power applications. Bluetooth LE has neither of these problems; it's simpler and lower power than WiFi, and already has ubiquitous device support so you don't need some other interface hub to plug into your network.

Note that the WeMo Insight switch (the one that's comparable to these, as it provides energy monitoring) costs $60, while these cost $45 each; which is a pretty big difference if you want to wire up a bunch of lights.

[1]: http://elinux.org/6lowpan/ROLL_support_on_802.15.4_radios

Maybe there are deficiencies in marketing. I have wanted for the longest time a solution to the problem of "my switched outlet is on one side of the room but I want my lamp on the other side". Seems like everything out there is overkill.

I suspect there are decent solutions for this but they're not well marketed, or maybe I just suck at searching for this particular solution.

There's another pretty similar Kickstarter project going on right now. It's wifi (802.11n) vs BLE - looks pretty sharp. It lacks beaconing but has a similar open API and also looks pretty well designed: http://www.kickstarter.com/projects/plugaway/plugaway-your-s...

Both have online load/consumption monitoring (I wonder how exactly the Zuli stores/handles that when there's no app around?), which are probably the biggest thing separating them from existing remote power outlet products.

(For logging power, the only relatively cheap options I've found is hacking a Kill-A-Watt sensor chip (see: http://www.mikesmicromania.com/2013/04/moteino-kill-watt-har... ) or buying a Watts up? PRO - both are more much more expensive/involved solutions than either of these two new devices.)

I believe that one way to measure the current for relatively cheap would be to break the neutral line and throw a current-sensing resistor in it. It would create a small voltage drop across the resistor. If you know the voltage drop and the resistor value, it should be pretty trivial to determine the current through the neutral line. Equation to do that would be:

lineCurrent = (Voltage of the current-sense resistor) / (resistance of the current-sense resistor)

Considering a current sense resistor is fairly cheap (http://octopart.com/13fr200e-ohmite-988758) it shouldn't be terribly expensive to do. You should be able to throw that between a Vin- and Vin+ on a linear optoisolator and send the values back to a microcontroller to be reported.

I'm not an EE though, so grain of salt.

Yeah, in theory you could build your own but having something UL rated is an advantage. AC is a lot more dangerous than DC, so you should really know what you're doing before mucking around.

There are a few more components for building a basic board: https://instruct1.cit.cornell.edu/courses/ee476/FinalProject... http://enerjar.net/Hardware.html

Building a more accurate power meter is pretty involved: http://coolarduino.wordpress.com/2013/02/08/power-meter/ http://coolarduino.wordpress.com/2013/02/27/power-energy-met...

Is it possible to use more than one device to control an outlet? As far as I know, Bluetooth devices can only be paired to one other device at a time. If that's the case here, then the outlet is tied to (for example) one phone -- but I might have a couple phones, tablets, and computers from which I'd want to control the outlet.

Bluetooth doesn't seem right for this - the range is just too short to really be useful.

It's interesting to me to see all these new fangled home automation devices come to market, especially when really inexpensive technology has been around for decades: http://www.x10.com

Is there a low-cost Bluetooth integration w/x10?

There's a library for a PC to control the wall warts; I've done some fun stuff automating power cycling with it. You could plug the USB-enabled controller into a server, and then write an app for whatever you like: web server, bluetooth, etc.

I've used x10 on and off since the early 80's. And... it sucks. When it works, it's cool, fun and cheap. But reliable it's not. For starts, all the inexpensive units I've used only support one-way commanding and the commands are susceptible to collision. Send a command to turn a light off and just hope that it goes off. Want to dim a light? All the commands are incremental so you'll have to do stuff like send 8 dim commands to get to a known minimum state then send 4 brighten commands to brighten to the desired level. And since it's one-way with no acknowledgments, you just hope that your commands were received and that the light was on to start with. Fun to play with, but I'd never trust it for anything but toy usage.

I've been using Insteon for a few years now (insteon.com). It's like x10 done right. There are acknowledgments, grouping, security, 256 brightness levels, extended commands, wifi+power-line communications, and a 6-byte namespace (for no collisions).

The title should probably read "Control power outlets via Bluetooth Low Energy"

http://en.wikipedia.org/wiki/Bluetooth_low_energy

It's BlueTooth Low energy, a fairly recent standard, the technology used in iBeacons. It's range is about perfect for a room. Several of the comments seem to be considering the older bluetooth standards.

Why is there nothing about security mentioned there?

Probably because it leverages the security built into bluetooth.

That does not reassure me.

"We discuss our tools and techniques to monitor and inject packets in Bluetooth Low Energy. Also known as BTLE or Bluetooth Smart, it is found in recent high-end smartphones, sports devices, sensors, and will soon appear in many medical devices. We show that we can effectively render useless the encryption of any Bluetooth Low Energy link."

https://www.usenix.org/conference/woot13/workshop-program/pr...

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