Beginner questions regarding regulation and rules.

[Mats S]

Hi!

I'm planning to setup some basic home automation and found openHAB which seem like a perfect fit. As I've had some experience with Java and OSGi.

The hardware I plan to use is raspberry pi with an i2c to 1-wire bridge (this is working right now with OWFS) and probably NEXA switches controlled with Telldus Tellstick.

I'd like to start small with the most (for me) useful features. What I want to do is

1. Control my car engine heater. I want to be able to specify a time of departure and depending on the temperature in the garage turn on heater x hours in advance. Nice to have would be to also be able to start immediately and run for 2 hours.

2. Regulate the the temperature of the beer that is fermenting in my dedicated fermentation fridge. I could probably get away with a simple thermostat function, but it would be really nice if I could write a more advanced control algorithm (PI or fuzzy) and also make sure compressor isn't running too long or too short periods of time. Another nice to have would be to be able to schedule setpoints for the temperature.

Is this feasible to to do with openHAB? I've started reading up on the concept of items and events, but I fear I have some distance left before I grasp how to best implement my requirements.

So questions:

How would you solve the car heater issue? Do I need a script that is called say every 5 minutes to check when next departure time is and read the temperature and decides if to send an event to turn on/off heater? How do I best call that script? Can it be done with rules? What would be the preferred way to set departuretimes, using google calendar integration?

What is the preferred way to implement regulation algorithms in openHAB? Is there some preferred way to schedule events to change the setpoint?

I'm absolutely not expecting anybody to solve my issues for me, but I would very much appreciate some feedback/hints from anyone 'further down the line' than me how you would go about this.

Many thanks in advance,

Mats S

[Marius Kotsbak]

kl. 14:06:21 UTC+2 fredag 5. april 2013 skrev Mats S følgende:

Hi!

I'm planning to setup some basic home automation and found openHAB which seem like a perfect fit. As I've had some experience with Java and OSGi.

The hardware I plan to use is raspberry pi with an i2c to 1-wire bridge (this is working right now with OWFS) and probably NEXA switches controlled with Telldus Tellstick.

I'd like to start small with the most (for me) useful features. What I want to do is

1. Control my car engine heater. I want to be able to specify a time of departure and depending on the temperature in the garage turn on heater x hours in advance. Nice to have would be to also be able to start immediately and run for 2 hours.

Hi!

I'm also interested in this usage. Did you find any solution?

Marius K

[Mats S]

Well, yes and no.
I have solved both my usecases, but without openHAB.
To control the car block heater I use tellus center and atd to schedule on/off + a simple web page written with libuhttpd to be able to turn on for one hour. Works good enough for me. I have also got a nexa temperature sensor in th garage, but I'm not currently using it as input to when to turn on the heater.
To control fermenting beer I wrote a new firmware for the stc-1000 thermostat (stc-1000+, you can find it here https://github.com/matsstaff/stc1000p).

I'd still like to try openHAB and add some more nexa units, but I have an abundance of other projects in the pipeline beore that :)

//mats

[Patrik Gfeller]

Hi Marius and Mats,

maybe the AlarmClock examples in the WIKI are helpful on how you can schedule events (controlled by the UI):

https://github.com/openhab/openhab/wiki/AlarmClock

with kind regards,

Patrik