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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

Parents

  • Hi Nico,

    I’ve been thinking about using a RPi and Node-Red also so it is good to hear it isn’t too bad getting started.  I am curious which esp-32 boards are you going to use...

    Frank

  • in reply to fmilburn

    Hi Frank!

     

    I just ordered a couple of inexpensive options of AliExpress. One is the same form factor as the Wemos D1 Mini 8266 type, which I think might be just right for my purpose. The other is slightly larger.

    image

    image

     

    Until they get here, my existing ESP-8266 based boards should do everything I need in the meantime.

     

    Cheers,

    -Nico

  • in reply to ntewinkel

    Thanks!  I have used the D1 Mini and liked it also.  How do you usually power them?  I have been using 18650 batteries in a carrier with a charger and boost converter but they are pretty bulky. 

  • in reply to fmilburn

      wrote:

     

    How do you usually power them?

     

    I've always just plugged them in, usually with a little iPhone charger cube - the real ones give a nice solid 1amp to work with. For the hummingbird feeders I was using dual-port USB chargers, where the other one powers a USB-hand-warmer to keep the nectar from freezing. The heaters draw too much power to make batteries possible, I think.

     

    I do have some small flat kind of lithium packs that I want to try. I've got at least one Adafruit ESP board that has support built-in for that. I was hoping to couple it with a solar panel. But then I can no longer be sloppy with my code image  I'd have to at the very least make it deep sleep a lot more.

     

    The other thought was to get an iPhone backup charging pack - some come with a solar panel built-in.

     

    Cheers,

    -Nico

Comment
  • in reply to fmilburn

      wrote:

     

    How do you usually power them?

     

    I've always just plugged them in, usually with a little iPhone charger cube - the real ones give a nice solid 1amp to work with. For the hummingbird feeders I was using dual-port USB chargers, where the other one powers a USB-hand-warmer to keep the nectar from freezing. The heaters draw too much power to make batteries possible, I think.

     

    I do have some small flat kind of lithium packs that I want to try. I've got at least one Adafruit ESP board that has support built-in for that. I was hoping to couple it with a solar panel. But then I can no longer be sloppy with my code image  I'd have to at the very least make it deep sleep a lot more.

     

    The other thought was to get an iPhone backup charging pack - some come with a solar panel built-in.

     

    Cheers,

    -Nico

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