Category Archives: Technology

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IFTTT (short for If This Then That) is a very powerful service that one can use to hook a number of different cloud services together in cool ways, and it’s a service I make a fair amount of use of.

Like many of us who make use of cloud services, the Snowden revelations, that the US and UK intelligence communities had hooks into all the major cloud services (or perhaps a better word would be “confirmations”, since many of us suspected this was going on for a while), have given me pause to re-evaluate the services I use and trust.

So then, what of IFTTT?

With all the hooks it has into other services, it does seem to represent the ultimate in back doors. Out of necessity of function, the permissions granted for each service are quite wide ranging, and we only have it on faith that they won’t be abused. Ok, so it’s not as bad as them knowing my password, since I can click a button and revoke access at any time, but until then IFTTT have full access.

As a US company, and through no fault of their own, IFTTT are compromised when it comes to security, since they’re all backdoored by the patriot act. I suspect that if they haven’t been forced to share access to accounts, it’s only because they are still relatively small fish (when compared to the likes of Google) and are only really used by the technical subset of internet users. But as they grow, it’s only a matter of time before they appear on someone’s radar.

In addition, their business model has always been a little bit of a head scratcher. I suspect the whole service came about from a “wouldn’t it be cool if…” kind of conversation, rather than a set agenda to make money (quite right too), but servers don’t pay for themselves, and I do wonder how long it will be before In-Q-Tel come calling.

Of course, it may be moot, since most of the services that IFTTT connects to are also US based, and for that matter, other countries are almost certainly forcing backdoors into their cloud services too.

Still, it’s got me pondering self hosted alternatives… any nice #indieweb projects out there?

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Screenshot-Dashboard - Google Chrome So, the other week I made a simple security device for my house, using a Raspberry Pi, that will (when I have a moment to wire it up), give a read out before I leave the house telling me if I have any windows or doors open.

Since I’ve been coding this Home API thing, the next obvious step is to wire the it up to the API so other things could make use of the data.

The first step was to modify the code running on the Raspberry Pi to transmit the status of each switch to a central server as a JSON POST request whenever something changed. On the server, I wrote a plugin which accepted this payload and stored for display, using the newly coded CouchDB support. This means that Home.API doesn’t have to poll the device, which would be more complicated and less efficient.

Sending data Home.API

Here is the client code, complete with Home.API integration:

The important lines of code are between lines 68 and 78. These lines check whether an update needs to be sent (we check for a state change in one of the lines we’re monitoring, and raise a flag if it is different from the last pass), and then package up an array of results as a JSON object and fire it over to Home.API using HTTP.

In our plugin

On the server, our class endpoint is loaded, and our decode method called. For efficiency we store this in a NoSQL database, which our display function getAll() just echos the contents off.

public function update() {
$result = json_decode(\home_api\core\Input::getPOST());

if ($result === NULL)
throw new \home_api\plugins\PluginException(i18n::w ('raspberrypidistw:exception:no_json_data'));

// Decode status
$this->status = array();
foreach ($result as $key => $value)
$this->status[$key] = $value;

// Create couch store
$uuid = \home_api\storage\nosql\NoSQLStorage::generateUUID($this, 'LastValues');
$couch = \home_api\storage\nosql\CouchDB::getInstance();

// See if there is an existing status
$latest = $couch->retrieve($uuid);
Log::debug("Retrieved: " . print_r($latest, true));
if (!$latest)
$latest = new stdClass();
$latest->status = $this->status;

// Store revision
Log::debug("Updating UUID:$uuid with " . json_encode($latest));
return $couch->store($uuid, $latest);
}

Pretty simple, have a play!

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So, building on what I did before with lights and switches as well as the stuff I’ve been hacking together with my Home.API, I thought I’d build something that may actually be of practical use. So, here’s a device that will tell you, before you walk out the door, whether all your doors and windows are shut, and for bonus points, tell you when they were opened and closed.

As you can see from the video, my local Homebase didn’t have all the bits, so you’ll have to use your imagination a little. The “Real” version would use simple magnet + reed switch burglar alarm fittings connected with bell wire to the terminals on your Piface. An indicator panel connected on the PiFace’s output panel should sit somewhere visible by your front door.

The software, again written in python, is very simple. It loops through all 8 input connectors and turns on or off the corresponding light when it reads a switch open and closed, when it detects a change it writes some output to the terminal and writes a message to the system auth log. This last feature is made even more useful if you configure the Raspberry pi to send its logs to a central server, as I have previously written about.

The next obvious thing to do is to interface this system with the Home API, which would be straight forward to implement (and I will implement when I get a moment!)

Here’s the circuit:

Click on the circuit to see a larger image…

securitysystem

…and here’s the code:

Enjoy!