[OpenTRV-interest] How I Came to OpenTRV

Alasdair Macdonald EMAIL ADDRESS HIDDEN
Fri Nov 28 23:13:14 GMT 2014


I note that the numbers aren't identical, however the devices are in
different locations in the room (compared to my Oregon sensor).

However, the two OpenTRV boards are closer to one another than either
of them is to the Oregon sensor, and their readings are fairly close.
I believe that they are generally within 0.2 degrees C of one another.

I also neglected to mention that I have a number of
remote-controllable light sockets, so these go on and off according to
various rules (time of day, local sunrise/suset, PIR activity).

When I first set up my hallway light to come on when there is activity
in the hallway, I discovered how surprising a change it is. It's not
that I lie awake at night trying to think of solutions to the terrible
problem of having to use light switches, but the fact of the matter is
that *not* having to operate a light switch is far more liberating
than I expected. Perhaps it's my age, but I enjoy being able to walk
from one room to another keeping my mind on whatever it was that I was
thinking about, without having to interrupt my thought process for
even a millisecond, to hit a light switch.

Likewise, I hope that when I have automated my heating, I hope that it
will become less aggravating than trying to figure out if I am too
hot/cold, and trying to twist my thermostat *just* the right amount to
effect a comfortable change. Of course being the architect of my own
automation means that I'll be thinking about it far *more* than the
average consumer, but that's one of the fun parts ... kind of.

Maybe I'll run some comparisons between my two boards and an Oregon
sensor, put them all together for a few days...

On 28 November 2014 at 20:44, Damon Hart-Davis <EMAIL ADDRESS HIDDEN> wrote:
> 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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