[OpenTRV-interest] How I Came to OpenTRV

[Alasdair Macdonald]

I realised today, looking at the stats I've been gathering via FHEM
from my two tinkering kit boards, that some of the information I am
collecting is similar to the data that I collect from one of my older
devices, also via FHEM.

It may help to explain how I came to OpenTRV, which is via Home Easy and FHEM.

Many years ago I purchased a pack of Home Easy remote controllable
wall sockets. The design has changed a little over the years, but you
can still buy a 3 pack such as this:

http://www.uk-automation.co.uk/products/Home-Easy-Remote-Control-3-Pack-Socket-Kit-.html

I'd been using such a pack for quite some time, essentially to switch
off a number of sockets connected to devices such as TV, computer,
hi-fi, overnight.

At some point I learned that one could send and receive the 433MHz
signals that are used to control these devices, via this little toy,
which connects to a PC:

http://www.rfxcom.com/store/Transceivers/14103

And I purchased one for £88. I used FHEM software to read the signals,
and discovered quite quickly how to send them via the web interface
and with programming logic. The beginnings of home automation. FHEM is
free:

http://fhem.de/fhem.html

A month later (and I can't recall if this had always been part of my
plan), I invested in some temperature sensors. Actually, I purchased a
mixture of temperature / humidity sensors; most have an LCD screen
whereby one can human-read the readings:

http://www.mendipweather.co.uk/oregon-scientific-remote-10-channel-temp-humid-sensor-for-wmr-series-thgr810/page-4.html?search=oregon&page=4

The price per piece for the models with readout is around £25, so I
elected to purchase one each of two alternative models, both of which
lack the LCD display. One reports temperature only; the other reports
temperature and humidity.

http://www.mendipweather.co.uk/oregon-scientific-wireless-temperature-sensor-thn132n/page-4.html?search=oregon&page=4
http://www.mendipweather.co.uk/oregon-scientific-remote-thermo-sensor-thgn132n/page-5.html?search=oregon&page=5

These 2 cheaper models are around £15.


FHEM did a perfect job of auto-detecting my new toys, and I only had
to issue "rename" commands to make the device names more
human-friendly.

So, for the past year I have been gathering temperature and/or
humidity readings from 6 locations around my house.

And here comes OpenTRV.

Since May this year, I have been gathering data from an OpenTRV board
that is connected to a different PC from my "live" FHEM installation.
During the warm months I simply gathered the data and didn't do much
to tidy it. Over the past few weeks I've reworked my FHEM code so that
I can capture and log data from both boards, via the board that is
connected to this PC, and with the aid of FHEM.

In the light of the readings that my boards provide - temperature and
luminance - and considering that I understand a humidity sensor is an
element in some versions of the board - I realised that I have been
capturing data using my 2-board tinkering kit that cost a three figure
(GBP) sum for me to capture with my previous kit.

Yes, the LCD screens on the Oregon sensors are very attractive and
useful, but instead of the £88 RFXcom device to communicate with
433MHz devices, I'm using a simple OpenTRV board to receive remote
data, and it works. My long term plan was to use FHEM to gather all
the data from my input devices, potentially with more OpenTRV sensors,
and use appropriate logic to decide when to open / close TRVs (of
which currently I only have one suitable model), however I understand
that OpenTRV devices should be able to do all of this by themselves.

To complete the picture, I also have about 6 PIR sensors; with ALL
sensor data being logged onto hard drive by a Raspberry Pi.

What struck me today was the capability of my locally-connected /
receiver board, which is performing for 868MHz signals what my RFXcom
device does for 433MHz signals. (The RFXcom device can manage a very
large number of protocols and that is one of its nicest features).

And I thought that it might be interesting to share this ...