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LCARS home automation with Arduino and Raspberry PI: QT redesign

6d ago

The connected home, the ultimate ideal in technology-driven luxury, promises easy living by passing along our drudgery to computers. But it’s not perfect. Even if you’re willing to shell out for expensive devices for your house, are you willing


Hi there, it's a long time since I uploaded my last video. The design of my last LCARS home automation was realized via HTML, PHP and C. Since my knowledge of HTML is quite bad, I needed another method to realize my ideas. I came to the conclusion that QT works fine for me. There are two programms running: First, there is "ha_interface" on the raspberry which on the one hand connects to the arduino via usb and provides a tcp server for clients on the other hand. Clients can request sensor values by sending "request:sensortype:sensorid" over a simple QTcpSocket. If the arduino sends an interrupt (for example: reed contact 1 is now open), ha_interface sends a broadcast message like "broadcast:reed1:opened" to all connected clients. Parsing of these commands can easily be done via the QString::split(":") function. The biggest problem was: I dont want the clients to poll for the reed contact state, since they change very seldom. On the other hand, I didnt want to miss that event. So I had to find a way how recognize an interrupt (by emitting a signal) in the serial usb connection. This gave me the answer: (part 5) and . Several connected clients can talk to each other via the interface and share for example their local "red alert on" or "system locked" bool variables. The second program, "ha_gui" is the LCARS design you can see in the video (the final version will get a dedicated 24" touch screen :-D). This program connects to the ha_interface programm via QTcpSocket. When switching an outlet, it sends "switchOutlet:syscode:groupcode:mode" to the interface, when requesting the temperature sensors, it sends "request:temperature:1" or something like that to the interface. If the main door is openend, the arduino will recognize that and send a message to the interface which then broadcasts that information to all connected clients. This LCARS client will play the "red alert" sound from Star Trek Voyager if that happens. Playing sounds is done via "QProcess::startDetached("aplay PATH_TO_FILE"). The "analysis of sensor data" at the top is realized via 7 QLineEdits. There is a QTimer which is called periodically, it generates random numbers and sometimes highlights a row. The LCARS design was created in QT Designer. There are stylesheet options for rounded corners and you can find official LCARS colors via google. The different views are realized by a QStackedWidget. There is still a lot of work to do, currently I plan to integrate PIR motion sensors and I am working on voice recognition via "simon" for ubuntu. This works quite well for now, but not perfect. The next video will show how I can switch lights via voice like in star trek ("Computer, switch on the lava lamp"). I'm also working on a mobile client for the Nokia N9. But since this is only a hobby project, this can take a while. In the last video there was the question why I did not use the raspPis GPIO ports. The answer is: Because I started playing around with the arduino firmware a year before I got my RasPi and it works very stable. Never change a running system ;) A second reason is that my software shall be able to run on any PC, regardless of having GPIO pins. The percentage of persons/geeks that only have a RasPi but not an arduino should be at an acceptable low level :-P. And yes, if it's working stable, I will publish the code on github or somethink else, but since I am playing in the code all the time, it is far away from being perfect or at least good code and I do not want to publish "my baby" in that quality ;)