[Julian] wanted a way to remotely control various appliances and lights around his house without spending an arm and a leg on home automation. He also desired the ability to easily switch what items he was controlling without a ton of hassle. Since he couldn’t find anything reasonably priced to do what he desired, he built his own SMS-triggered remote control system.
He designed his system to be used like an extension cord, hence the portable junction box enclosure. This enables him to regulate up to four different items at a time, with the ability to swap out components or relocate his controller at will.
The power strip is controlled by an Arduino which receives commands from his PC via an Xbee module. Any text messages sent to his Gmail account are retrieved by his computer and then transmitted to the Arduino. The Arduino in turn triggers relays as designated by [Julain’s] text messages, utilizing H-bridges to provide the required current.
Check out his schematics and code if you’re interested in implementing something similar in your home.
Scumbag builder. Doesn’t want to spend money on build. Uses SMS.
I don’t really understand why he is a scumbag builder.. He is in a school dorm not like he can rip up the walls of the room.
Please define “scumbag”. I don’t see anything wrong with this project; on the contrary, I think it is simple, elegant, and clever.
I agree, scumbag doesn’t seem right. But I disagree as this project IS clever, but not simple or elegant. elegant is cell phone module in the plugin… this is a computer, arduino, wireless and the plugin assembly… but no monthly bill I suppose.
:D Know your meme! Try googling scumbag steve.
TIL Reddit and HAD share few common viewers.
Nice build… nice work from SMS to power.
Isn’t the Arduino necessary? The XBee has digital IO pins on it. Is there any reason not to use those directly instead of signally the Arduino and then using the Arduino IO?
TYPO: Isn’t the Arduino UNNECESSARY?
while we’re pointing things out ;) that’s a double negative.
“Is the Arduino necessary?” is optimal.
yeah… I would agree, perhaps there were extenuating circumstances
I love this build. I’ve been wanting to do things with SMS but cellular interface stuff is way to expensive.
For Example:
http://www.sparkfun.com/products/9607
The idea for the form factor of this build is great to keep it mobile but I may have taken a different approach. I never liked having a junction box sitting about, looks tacky. A cheep power strip could give this build a nice facelift! We as hackers need to start thinking more like product designers and consider not just what something does but how it looks to people. Even a cheep project enclosure can turn a pile of wires and circuit boards that people say “You built that… I can tell” to into something that they will look at with awe and proclaim “You built that! I can’t believe it!”
Great build none the less!
The problem with a cheap powerstrip is it doesn’t allow for individual controls. A powerstrip generally is a fuse switch with two rails (think train tracks) with a plastic filter to accept plugs. However, with the junction box, he can get divided sockets, allowing him to control 4 outlets independently.
DooWeNo is obviously a lurker of Reddit.
Scumbag Lurker
Agreed
Agreed.
I would be reluctant to build this
due to safety concerns.
No circuit breaker or fuse is used, like on a commercial power strip.
No protection diodes on the relays.
Fair enough. Add a fuse to the input or output circuits (or both). And there aren’t any diodes on the relays because they are driven from H-bridge motor drivers and a motor and a relay are kinda similar devices.
uhh… The power from the outlet will be limited to 15A (or 20A in bathrooms/kitchens) via the breaker panel.
adding a cheap bluetooth module would cut the cost of sms and need for computer.
True, but then you wouldn’t be able to control it if you were out of range of the bluetooth transeiver.
If the computer is always on anyway (mine usually is, for various tasks), the use of the computer wouldn’t really be an issue. This way, you could also use the computer to control the device, either manually, using scheduled tasks, based on other data (say, turn on a light if you have a new message), or through a remote web interface, eliminating the use of SMS altogether.
Also, one thing you really need with home automation is reliable communications and responsiveness. Nothing more annoying then the system not responding each and every time or taking longer than a second to do so. This is why I’ve gone w/Insteon since they have reliability down pat and they communicate fast over the mains and have an RF link, and use handshaking for improving comms in a busy or marginal network. I have written my own software with a web interface for controlling events, scenes, triggers, etc and am considering making it open source.
I would have liked to seen inside the box.
I use Insteon in my house, which can be expensive, but works really well. I wrote all my own controller software so that saved a bunch.
I wonder how much delay is introduced by doing SMS via google? It’d be annoying to mash a button on your laptop and then have to wait 30 seconds for your lamp to turn off.