Thermostat Progress

Nextion Node-Red Thermostat

I’m quite chuffed. Having finally managed to make a new working Node-Red on a Pi2, with a copy of all my work, so that I’m no longer losing sleep over losing the lot, I can finally start to get more ambitious with my thermostat over at Hollyberry Cottage.

I’ve had this design for a little white – a Nextion display (400*240) talking serially to the Raspberry Pi2 which is controlling the heating. The big lettering is obvious – the current temperature with humidity in small text underneath the temperature. To the right is a manual control. At the top a menu system, down at the bottom the weather outside according to the open weather node on the Pi2’s Node-Red.

tmp4AD3Status – W/E changes from week to weekend depending on the day and also indicated whether or not the heating is in manual override mode (right hand controls).

Then there is the time and date but I wanted more… and the little sliders available to Node-Red you see in the coloured area. One is being used as a level – the other two, simply on/off indicators. The orange bar decreases in length over time showing the amount of time left in the current program (5 program times and temperatures a day – separate at the weekend – I’ll do more when I Node-Red-UI gets to using less space for controls).

The two little blocks on the right are just for fun and change once a second. The first one is merely an indication that the unit is functioning – the second is more fun. I have an installation of Node-Red in Spain – and that has a one-second ticker which broadcasts in MQTT. I pick up that message and depending on the state, alternate the right block between 100% on (green) and 0% (black) – Hence at a glance if it is flashing, all is well in my Spanish installation.

I plan to make much more use of those simple level indicators both for analogue values and just on-off – improved visually by some static background frames I’ve yet to define.

All great fun. Oh and I have JUST thought of another great idea but I need room for a button – a speech button to read out the information and more using the Ivona speech flow I blogged about some time ago in here.

The thermost at Hollyberry Cottage controls an ESP8266 relay to the heating and reads temperature and humidity from a DHT22 module attached to an ESP8266 and transmitting the info back to Node-Red via MQTT. The next improvement will be to put sensors in different parts of the house – for example when asleep we’re not concerned with how warm or cold it is in the living room, we only care about the bedroom temperature – so it makes sense to attach input selection to the various timing periods as well of course as temperature.

As soon as I get my new office (currently a concrete based sitting under the snow) in place in a matter of weeks I plan to make a much expanded user interface using the 7” display which has 4 times the pixel area to work with.

This just keeps getting better.


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