[OpenTRV-interest] How I Came to OpenTRV

[Damon Hart-Davis]

This will surely become part of OpenTRV’s creation myth in the fullness of time…  %-P

Do you have any view on the accuracy/precision of the OpenTRV temperature measurements vs your other gear for example?

Rgds

Damon


> On 28 Nov 2014, at 20:14, Alasdair Macdonald <EMAIL ADDRESS HIDDEN> wrote:
> 
> 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 ...
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