Arduino Opla - IoT Kit

Yyou might be right about the privacy issues!  Today I received an email from Hive (Centrica/British Gas) that my thermostat is using too much battery power so they are going to send me a new one.

Very interesting. I can see much of what is implemented being to the consumer's benefit regarding these common home automation products - such as your story which they will hopefully save you from replacing the batteries (at cost) needlessly....so a really good thing. I don't think I'm even too worried about getting placed adverts or emails suggesting wool jumpers or double glazing because the temperature is turned up too far and my house is obviously not well insulated. Actually I don't know what I'm really cautious about with these devices, but I do like knowing I am able to check opensource firmware so a bottom up build is always good. Hence my interest in this Arduino kit whereby the project functionality can be completely understood. Downside is I'll spend hundreds of hours to make something which isn't even comparable to the commercial products, nor as slick

Very interesting. I can see much of what is implemented being to the consumer's benefit regarding these common home automation products - such as your story which they will hopefully save you from replacing the batteries (at cost) needlessly....so a really good thing. I don't think I'm even too worried about getting placed adverts or emails suggesting wool jumpers or double glazing because the temperature is turned up too far and my house is obviously not well insulated. Actually I don't know what I'm really cautious about with these devices, but I do like knowing I am able to check opensource firmware so a bottom up build is always good. Hence my interest in this Arduino kit whereby the project functionality can be completely understood. Downside is I'll spend hundreds of hours to make something which isn't even comparable to the commercial products, nor as slick

They do monitor usage.  Every month I get an email telling me average daily temperature, average setting and how that compares to other Hive users in my neighbourhood!  To a certain extent it’s a bit creepy but it’s not like Google or Amazon listening in and keeping recordings of conversations, or widespread tracking like Facebook. 

When they email me about batteries needing replacing, I go and check the thermostat and can see the battery indicator - they have never emailed earlier than necessary.  In fact, they emailed me in November and I changed the batteries; then they emailed again towards the end of December and I thought it was just telling me the same thing and I ignored it.  Until I woke up a few days later to find no hot water or heating!  Hence the follow up email to tell me they are replacing it.  Not bad given it’s over 4 years old.

It is one of the drawbacks to a smart thermostat: it’s great that I can set the hot water on and heating on over the internet, when I’m about to come back from holiday, but when it stops working, heating and hot water need manually turning on.  We rented a cottage in Devon a year or so back that had Hive heating: the thermostat wasn’t working when we arrived so that needed a few hours to sort out and only the owners, in Scotland, could adjust settings.  Every morning I had to jump out of bed and turn on the heating override and then jump back in bed again!  Mrs wasn’t best pleased.

It’s certainly an interesting idea to build your own though.  At least you can do away with the hub and build in fail-on function.  I presume it would be hard wired to the existing thermostat wiring.

I too knew someone who moved into a new rental and the Hive controller had a flat battery, landlord was only up the road so he popped in to replace it nice and quickly.

My current room thermostat is hardwired with Twin and Earth (T&E) cable to the programmer: it has a simple switched live connection back on one of the conductors. It would be feasible but against good practice to use the earth for a 'low voltage switched return' whilst the other two conductors were at 240v. I could use an isolated transformer fed from the live/neutral conductors at the thermostat position (luckily its on a hollow wall) and then another Arduino or ESP8266 unit at the controller so the on/off signaling is via the WiFi. The other idea is to use all three existing conductors of my T&E at low voltage - power the Arduino and get a switched return signal, feed that to a relay to obtain the 240v and into the existing controller/boiler, which I think is safer....until someone modifies the house in later years, finds the T&E cable midway and decides to tap into it to make a local spur outlet !

14rhb  wrote:

My current room thermostat is hardwired with Twin and Earth (T&E) cable to the programmer: it has a simple switched live connection back on one of the conductors.

I have a Drayton Digistat 3. which uses the same Twin and Earth wiring as the original simple thermostat, so it only switches the boiler on and off.

However, it allows me to program different temperatures for various time periods during the day:

eg 06:15 - 08:30 = 22 deg, 08:30 - 12:00 = 20deg, 12:00 - 14:00 = 22 deg, 14:00 - 17:00 = 20deg, 17:00 - 22:00 = 23 deg, 22:00 - 06:15 = 17deg

The actual times, number of time periods and temperatures are completely flexible. The settings can be different beween weekdays and the weekend - 5/2.

A very important additional feature is the "holiday" setting. This allows you to set a fixed temperature, of say, 17deg, for the period you are away and for the normal temperature cycle to resume automatically the day you return - or earlier if you so choose.

I chose the Digistat 3, because of its flexibility and the simplicity of installation - direct replacement for an old, simple room thermostat - and, of course, cost.

Neil