Calaos OS

What is Calaos OS? That question is asked quite often.

Calaos is not a single software and if you want to get a full Calaos stack running and configured you need to setup all the following softwares :

  • calaos_server
  • calaos_home
  • calaos_web
  • A web server (for serving calaos_web)
  • Configure SSL and certificated on your web browser. It’s needed if you wand to connect to calaos_server remotely, it’s the case for calaos_installer and for the mobile application. SSL is there to guarantee that the connection between your mobile and calaos box is encrypted. Otherwise all the informations you send are readable.
  • Compile calaos dependencies (EfL and Elementary)

Some people have skills to get all this stuff running on regular Linux distributions, but for the majority of people, that’s not the case, and they should use Calaos OS, as it embed all the required software in a single image. It’s also covering a lot of hardware configuration and their specificities. The Idea of using Calaos OS is to keep all the hard and complex work of integration inside Calaos OS, and give to the users a real good experience.

Calaos OS repository :

Calaos OS is based on the Yocto/OpenEmbedded. This is an amazing build system, which allows us to create a specific GNU/Linux distribution four our specific needs.

In our case, the Yocto version we are using is Yocto 1.5 (Dora). We are using systemd as for the init process, XOrg for the graphics stack. and Connman for the nework manager. Calaos server and Calaos home are started at boot. For calaos-web we are using Lighttpd to serve pages. We are also using EFL 1.7

If your electronic board, or your PC is not currently supported by Calaos OS. It’s most of the time just that we never tried it. So it’s maybe not a big thing to add your new architecture in Calaos OS. If the architecture is supported by Yocto, there is a lot of chances that adding it to Calaos OS is easy. Take a look at to see if a yocto BSP exists for your hardware.

Even that it’s simple to add a new architecture, it takes a lot of time and space on your harddrive to build a full image of Calaos OS. So please be patient and keep in mind that you need a real big machine to build an image. Currently i’m using a Core i7 machine with 8GB of ram, and it take arround 2hours to build a complete image for Raspberrypi.

Building your own image is easy to do, just follow the steps in the Calaos OS Readme :

If you get into troubles, don’t hesitate, to ask questions on the forum : or on IRC (#calaos on We will guide you.


Calaos and 1-Wire

1-Wire is a communication bus, wich uses only 1 wire^W 2 or 3 wires for communications between slaves and a master. One of the most common 1wire module is a temperature sensor, the DS18b20. This is already calibrated, directly on the production line, and like all 1wire chips it contains a unique identifier.

The DS18B20 has an operating temperature range of -55°C to +125°C. And the sensor is accurate to +/-0.5°C over the range of -10°C to +85°C. And it’s cheap, you can find it for less than 1€. You can even found a waterproof version of this sensor.

As it uses only 2 or 3 wires, it’s easy to add this kind of sensor in a house or an appartment, you only need a pair of twisted wires, like the one we found in ethernet or telephony cables.

On the home automation box, you need an hardware interface to communicate with the sensor, and a program to talk with this interace. Calaos and more specifically calaos-os integrate such sofware : owfs

For the hardwre interface, you have 3 choices. If your home automation box, is a Raspberrypi or an electornic card with GPIOs, you may use the w1 linux kernel driver. It emulates a 1wire master with a single gpio. The only thing you have to do is to connect 1-wire sensors to the Rpi GPIO like here :


As you can see, 1wire is a bus so we can chain temperature sensors.

Now on the sofware side, once you have calaos-os installed on your Raspberrypi, you need to load the w1 module. It’s responsible to handle the communication with the sensors.

modprobe w1-gpio

modprobe w1_therm

I guess you want this changes to be persistent over reboot of the rpi, so to do that create a new file named w1.conf in the /etc/modules-load.d/  directory. And add those two lines :



Now we have to configure Calaos to add the 1wire temperature sensor.

On your computer, launch calaos_installer. Auto detect calaos server by clicking on the Auto Detect button. The IP of calaos_server should appear in the list. So you can connect to calaos_server and download your configuration.

Now add the 1wire temperature sensor, click Add Item -> 1wire -> temperature sensor


Name is the name that the sensor will take in all Calaos User Interfaces.

Sensor ID, is the 1wire ID. It’s unique for each sensor, and can be read on the sensor itself, it’s something like 28.A691B4040000. (It’s really small on the sensor, but i swear it’s written)

Finally the OWFS argument, is the argument taht will be passed to owfs to initialize itself. For w1 kernel driver, it’s –w1

Save the config, upload it again on you home automation box. And the new temperature should be displayed on Calaos Home, Calaos Mobile or Calaos Web.

If you don’t have, or don’t want to use GPIOs, and solder the sensors by yourself, you can choose an easier solution, and connect an USB module : the DS9490R module and connect 1wire sensors with RJ11 cable. On Calaos side, it’s exactly the same configuration. The only point is to change the OWFS argument, and use the “-u” argument instead of “–w1”.


There is also an other solution, with an ethernet device on which you can connect your sensor, and then the communication between your Home Automation box and the module goes through ethernet. This solution should also work on Calaos (well somebody said it worked), and you might change the OWFS arguments and add the ip and port of the Enet server like this : “–enet= -p 4304”


Calaos Rules System #1

A question that comes very often in Calaos is “How does the rules system works in Calaos? How to do [name what you want here]?”. I’m going to start a series of posts to explain that with some real examples on how it actually works and how to do advanced tricks with Calaos. So, lets start with the basics.


At the root of the entire system sits calaos_server. This is the main component of the system and its purpose is to talk to the underlying hardware (Wago PLC, 1-wire, Zibase, MySensors, …), execute some user defined rules, and export some API for the different user interfaces (calaos_home, calaos_mobile, webapp, …).

calaos_server acts as a daemon process and do what the user has configured in calaos_installer. Two types of configuration needs to be done, first declaring Items and devices in rooms (left part of calaos_installer), and finally creating rules using those items (right side of calaos_installer).

Calaos Installer

IO and rules

In calaos, all items declared are directly accessible from any user interface. For example, if you create a light, you can control that particular light on any interface. But when you create a switch, it will not do anything unless you create a rule that tells calaos what to do with your switch and eventually do an action like switch on or off your light. This is where rule comes in. A rule is basically an action that is triggered by an event. In our switch/light example, the event of pressing the switch will tell calaos to execute an action on the light.

Any rules are composed of a trigger event list and a actions. An event can also have some condition, but we will see that in a later post 😉

Basic example

Let’s start with a basic example of a switch that can switch on/off a light. First create our two devices, a switch and a light.


Next we are going to create a rule by clicking on the + button in the top right. Enter a rule name and type (for categorization) and click Ok. A new empty rule is created. You will see an empty condition list, and an empty action list. Let’s add the condition by dragging the switch in the condition list.


When adding a condition and clicking on it, you will see a popup appear. Here you can configure the condition. For now we can use the default values that means the event of: When the switch is pressed (true means the switch is active).

The first part of the rule is done, we need now to add an action to be executed after the switch is pressed. Lets drag the light to the action list.


The same kind of popup appears after adding the light to the list, it will let you configure what action to do for that particular light. Every items supports different kind of actions. The default action for a light is toggle which means invert the light state on every rule execution.

Now we have seen how to create a basic rule to handle a switch press that will toggle a light. Of course the same thing can be done for all the items and devices in calaos. All hardware devices (shutter, temperature, …) can have different actions or events, and calaos_installer tries to list them all in the action list.

In the next post we will see how to create more complicated rules. Calaos can also have some virtual items (timers, time ranges, variables, …), and they behave exactly the same regarding the event/action system.