BTY AAA1350, rechargeable NiMH batteries - first and last impression

Right, since they were not that expensive, I somehow did not make the effort to search on the net for reviews, so I ended up with a pack of BTY AAA1350 rechargeable batteries. From the packaging, they went straight in the charger for evaluation - first discharge with 100 mA, then fully charging them with 200 mA current.

The results are more than disappointing. I should have run the TEST mode of the charger, which should have reported the capacity upon discharge, but this value is usually less that the value during the charging. Anyway the numbers are so bad that this does not matter. One battery stores 78 mAh which essentially means it is completely death. The other three were about 270 mAh which actually fits the reports from other discussions on the net.

Weather station Prologue IW006-DCF (Clas Ohlson 36-5364)

Well... on this one. Let's start with the good.

Advantages:

• Very nice weather station with color display that does not need Internet to show the weather! Everything else I found wanted to show me some nice pictures, temperature and forecast from some weather service. I can easily use my 3 years old tablet for this, if I wanted.
• Indoors and outdoors temperature and humidity readings. It has wireless remote sensor that pair with the station without any problems.
• Constantly lighted large screen where the time numbers are the largest - yes that is what I want!
• Radio time synchronization - it has the most stable synchronization from all of my clocks with such feature.
• Battery backup.
• Pressure sensor with some sort of forecast.

Disadvantages:

Eaton 3S 550 and Raspberry Pi

Briefly about the setup: Eaton 3S 550 powers a constantly running Raspberry Pi (RPi), wireless router, ADSL modem, cordless phone, wireless energy monitor (Eliq) and home automation device (Tellstick Net). All in all they are 10% of the UPS capacity which gives me about 30 minutes safety window before the RPi will shut down (shut down is triggered when battery is below 20%).

The Raspberry is running latest Raspbian and monitors the UPS using Network UPS Tools (NUT) which can power off the computer, send notifications etc. I have set up script to log the events and get an SMS on power failures (using Android phone and SMS Gateway).

Below is a screenshot from the NUT monitor GUI and results from a test run of the setup. I have manually started a bash script to collect the battery status by pooling every 15 seconds with "upsc eaton3s@localhost | grep battery.charge:"

Tellstick Duo revisited

For one or another reason I have replaced/upgraded my first Raspberry Pi (RPi) /256MB RAM/ with the latest RPi2 - the advantages are kind of obvious. I used to run the old telldus-core and now it was perfect time to upgrade it and rewrite my programs written in python with bash script using the new features in telldus-core-2.1.2.

I have tried before but failed with the device recognition and lost my patience to find the cause for the problem i.e. missing controller configuration - here is the solution.

There is really nice way to compile everything in a very clean way: instructions written in Swedish (perhaps here as well ). I got tempted to try the GUI suggested there but the repository was 5 years old which was clear NO to me.

Anyway, before I had python program running as a daemon to log selected device events and automate different switches + poor man's security monitoring solution. The only reason I was using python is to catch device and sensors triggered interrupts.

Universal thermostat CE UT-200

There is not much to write about it. It is an digital thermostat that one can easily use to maintain temperature below or above certain value. Conveniently enough, depending on the "on" and "off" setting you can set the thermostat in heating or cooling mode.

We have small room attached to the house that is not centrally heated and during the winter gets easily quite cold. We use it as gym, so maintaining a temperature around 5 degree seems reasonable enough (one can easily heat it better but of course it reflects on the electricity bill). I have hooked a regular 700W passive heating element that has its own digital thermostat, but that one is only regulating the temperature of the element.

I have Raspberry Pi that receives the temperature readings from outside and the room and in principle I can just use a regular remote switch that could be controlled by the computer. Except, that my philosophy is that I want to have a centralized system that controls the stuff around the house, but I want it to be also autonomous. I have the network version of the home automation module (Tellstick NET) and on couple of occasions when the internet connection was lost things could have got confused... Luckily, the local version (Tellstick Duo) is running independently. Unfortunately this one is also prone to failures, despite that it is running backed by UPS. So here is how I ended buying the thermostat.

Here are two graphs from the monitored temperature in the room (green line) and outdoors (red line), just to illustrate how well it works. The thermostat is set to switch on the heating below 4.5 and switch it off again above 5 degree Celsius.

Since it works as expected, I just need to mention the single disadvantage - it speaks German ;-)