This project uses a Wemos D1 mini + Thermistor to send temperature info about my pool to Weewx. This is related to some other projects I've worked - my Arduino/Hubitat pool controller, my weewx hubitat driver to get my temps into devices in Hubitat, and my home weather station project. I was using an acurite soil/water sensor for my pool, but after 2 seasons, it was toast - so instead of investing more money in a crummy company like Acurite, I figured I'd build something that can get the job done in-line to my pool. I've got some other Hubitat contributions if you're interested.
- Acurite is crummy because they discontinued a perfectly good internet hub device with little notice, and forced people to buy a new device that had less functionality that the prevіous hub. Not only this, they took away the ability to get your local weather data off of the hub itself. So the only thing left that I have of Acurite is their 5in1, and when that dies, I'm abandoning them. Today I'm pulling data off the 5in1 via SDR and getting pressure data via a bmp280.
- Inline, Waterproof pool temperature sensor. I used this exact device, thus my arduino code won't change much if you buy this model. You should measure the resistance of your 10k resistor as well as this at 25 celsius to better tweak your values.
- Wemos D1 Mini ~ $5/each - this also assumes you have a USB cable & the arduino build environment - optionally, you may want the WebOTA library as this will enable remote updates via web should you wish to update your code (and for some reason the native Arduino OTA method isn't working - it's finicky).
- 10k resistor
- Weewx. Not a requirement as the above sensor will work for serving temperature to any device that can make a web request, but the PoolService module will enable this natively in Weewx.
- Case. Print this at 104% because of D1 mini tolerances.
- Wire up your Wemos D1 Mini this way (yes, this isn't a Wemos D1 mini, but the pins are the same - A0, 3v3, Ground and pins on your thermistor). Make sure your resistor added as well. Since these connections are so simple, I didn't need a breadboard and just soldered them to the board. I know the image below shows D0, but I had to use A0 instead.
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If you want to use ST_Anything (a hubitat thing and NOT Weewx to get the temp from your temp sensor), you can use this code. Otherwise, if you want to connect this to Weewx, skip this step. This file has also been configured for these thermistors, not the one above. You will need to adjust values as needed if you want to use Hubitat and not Weewx.
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Connect to arduino via USB and load arduino_pool_sensor.ino. Adjust wifi info and any sensor parameters at the top. I essentially tweaked the numbers based on several days of comparisons with other thermometers to get it to be as accurate as possible. YMMV. You can also adjust +/- the temp via the weewx configuration, so it doesn't have to be perfect. You should see IP info via Serial Console, so connect to http://your.ip.address/temp to see the temp. If it's grossly off, check your resistor and make sure you're on 3.3v not 5.
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Setup the weewx configuration as per the instructions on the top of pool.py. pool.py itself goes in the weewx user directory - this is in /usr/share/weewx/user on my machine. make sure to add the PoolService entries in weewx and enable pool.py in the data_service line - this may be commented out, or you may be using other services - it really depends. For me, I have two extra data services so mine looks like this as I have a bmp280a that I am using here for pressure:
data_services = user.bmp280a.bmp, user.pool.PoolService
- When you're measuring an accurate temperature, install your sensor (note; if you have a heater, make sure to install this before your water is heated, not after) and install your Wemos D1 Mini into a water proof box - I just added it into my pool controller box and shared the power with those relays.
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