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  • Author Author: ntewinkel
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Raspberry Pi and Node-Red for local temperature monitoring

ntewinkel

I just took another step in a project that has been going on for over 3 years now: temperature monitoring using ESP-based boards.

 

It started out with an ESP-001:

Remote (Water) Temperature Monitoring

 

Since then I've made a few updates, including switching to using Wemos D1 Mini boards instead of the ESP-001. The Wemos D1 Mini boards are much easier to program and power, plus there are lots of little Thingiverse 3D printed case options available. I've ordered some ESP-32 boards for the next step forward too image

 

I've also had to update the html on the server to use a different graphing library, as Google seemed to have changed or discontinued the one I was originally using.

 

For the last year or more I've started to wonder if I could maybe use Node-Red on a Raspberry Pi instead, to simplify the server side work, and also to maybe make things look nicer.

 

So a few weeks ago I installed Node-Red on a Raspberry Pi 3 I already had here, after purchasing a new 64GB high-speed SD card and re-installing a fresh image on it. Turns out those cards are quite affordable now. I bought one on Amazon and yes - I tested to verify the speed and capacity before trusting it for actual use image

I had toyed with the idea of using an external SSD drive, but that's more cost and complexity that I probably don't need right now.

 

I followed a few tutorials on how to install Node-Red and did the basic hello-world type of things to try it out. I was surprised at how much easier it actually was than I thought it was going to be!

 

Tonight I spent maybe an hour and a half and created a little browser-based dashboard to display my local temperature and my own sensor temperature.

I obtained the local weather office temperature from OpenWeather, which was also far easier than I thought it would be.

Getting my own sensor data was a little more tricky, but with a bit of digging I was able to read my own stored values from my server, converted it to JSON, and pulled out the temperature from it.

 

All in all the update tonight only took maybe an hour and a half of messing around.

 

This is the result:

image

 

It also looks great on my iPhone.

 

For the next steps I plan to:

1. Update my temperature sensor devices to use MQTT. The plan is that they will publish their values via Mosquitto, which I plan to install on the same Raspberry Pi.

2. Store the temperature data into a database (I think that's Ingress? I'll have to re-check some Andreas Spiess videos for that). edit: It's InfluxDB I was thinking of. Time-series data that automatically tucks in the aging data.

3. Show the historical temperatures in charts (edit: this may involve Grafana too)

 

The only drawback is that this removes my Internet access to the temperatures, but I usually only look at it while at home anyway so that's not a big deal. I'd rather not expose the Pi to the outside world so it'll likely stay that way.

 

Best,

-Nico

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  • Hi Nico,

     

    Thanks for posting. That was very helpful to me in understanding what node red can do.

     

    I see that I can istall node red on my Windows PC and do a similar sort of thing to you. When the gardening season slows down and I have more time, I might well get to grips with it.

    I always seem to ride on your coat tails! image

     

    Neil

  • in reply to neilk

    Hi Neil!

     

    I'm glad to see I'm not alone trying to do this kind of thing image

     

    I did also get MQTT installed and receiving data from one of my sensors - I had to make some relatively minor changes to have the sensor send via MQTT instead of to the server. The biggest hiccup was that I had the sensor connecting to my guest network, which is blocked from accessing my home network, where the Pi resides.

    ps, MQTT was a one-liner install... old examples show some very complicated maneuvers!

     

    -Nico

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  • in reply to neilk

    Hi Neil!

     

    I'm glad to see I'm not alone trying to do this kind of thing image

     

    I did also get MQTT installed and receiving data from one of my sensors - I had to make some relatively minor changes to have the sensor send via MQTT instead of to the server. The biggest hiccup was that I had the sensor connecting to my guest network, which is blocked from accessing my home network, where the Pi resides.

    ps, MQTT was a one-liner install... old examples show some very complicated maneuvers!

     

    -Nico

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