The Thermostat Continues

Hard to believe the amount of time I’ve spent on this thing. I’m still too deeply buried in R&D right now to fully develop another full article on my thermostat but here is some info to add to the previous blog entry on the subject. My Node-Red/ESP-GO thermostat is now in operation with three stat heads, 2 in active service as one has an issue whereby it locks up occasionally, maybe once a day, maybe once every couple of days – unpredictable – a hardware reset brings it back – but I need to get to the bottom of it – the other two units don’t do that.

The 2.5w laser engraver turned out to be less of a blessing than it first seemed, thanks to it’s inability to handle clear Perspex (does a lovely job on coloured material) I’ve had to go back to traditional DIY techniques for this project.

While I’m here, I’ve just reduced the e-newsletter frequency as we’re getting ready for the summer exodus to the sun and that will impact my writing ability somewhat until early April when I hope to have lots of new toys to talk about.

I’ve now published updates to ESP-GO-3 using Espressif Non-OS SDK 3.1 – which in itself is still only on GIT at the time of writing but seems to work a treat. My thanks to helpers on the Espressif forum – I didn’t really need this for current projects but the 5K of saved iRam gives me bags of room for expansion, so now was as good a time as any to upgrade to the latest SDK. Perhaps in the summer I’ll take a look at a better web interface and more SSID options.

Some new visuals – here is my Grafana logging – accessible externally thanks to PIVPN as is the stat itself.

Grafana Logging for Pete's Stat

Above is my Grafana info screen – monitoring and logging the two stats (main and aux – I have a third on test, all have now survived power cycling both for the stats and  Node-Red without failure or needing intervention) but I’ve seen dropout after 2-3 days needing power cycling on one of them so the jury is still out). I’m also monitoring (temperature in the hot water tank cupboard from the mains controller supplying on-off instructions to the air—source heating system.

Lots more below the line…

The main (green) sensor is currently at 22c (air source takes ages to reach full set temperature) and that is the sensor in use (aux in yellow is a fall-back).  Humidity is for reference only – ultimately I’ll factor that into the heat supply as it generally FEELS a little warmer when the air is dry.

Here below is the stat as it appears online (only via PIVPN, deliberately). The TOP green readout is high resolution but I’m only actually using integer resolution – why bother being SO accurate when the difference in temperatures is well over 1 degree from 1 metre above ground to 1.5m and from one side of the room to the other. There IS however a use for the more accurate reading, as turning the heat off when the stat reaches set temperature means it will only ever stay AT the set temperature for a few moments. Really need 0.5 degree overlap.


Final colours will likely be more subtle – recommendations? And yes, the temperature does need to rise quite early in the morning – on really cold mornings there is a lot of lag with air source heating before radiators get up to full temperature. As you can see, the Nod-Red flow is getting way too big for one screen. Most likely now unreadable even on expanding but hopefully it will give you some idea.

The stat flow

The actual physical stats are starting to look  ok, would be better if I had a decent engraver. Below, stat4 on test minus it’s up-down buttons on my bench, working on USB and with it’s plastic screen protector still in place. Stat3 is boxed, running on its own internal mains power supply and in the house, getting the spouse-test. 2 days without issues.

These stats are deliberately simplified allowing limited up-down temporary temperature change and monitoring of local temperature and humidity as well as SET temperature monitoring and heating status with WIFI signal RSSI thrown in for good measure.

Stat4 on test

And here is one of the “boxed” units… in my office which is always warmer than the house and therefore the worst place to test stats… this one now has buttons that light up when pressed. I just wish the buttons had an overhang.

Boxed stat


6 thoughts on “The Thermostat Continues

    1. The Graphing capabilities / flexibility of Grafana far exceed anything I have ever seen the Node-RED GUI can do. I am actually running similar data into both at the moment and the Grafana package allows far greater control of the visual aspects. It all depends how much information you want to display / derive from the graphs.

  1. I am trying to find the Espressif NONOS SDK 3.1. Do you have a link to this? In due time I want to try to get ST7735 also functioning on your ESP-GO-3 locally by cloning it.

  2. Peter, what's your technique for cutting the plastic in hobby boxes? I tried dremel and hot knife, but I never could seem to get clean edges.

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