So I want to build a floating pool thermometer with an esp8266 to post the data to a website so you can always check the temp. The issue is being a pool float it kind of needs to run on batteries and recharge with solar. I was looking to use the sparkplug thing as the main board but my question is how to charge the attached lipo with solar. I doubt just wiring a cell up to the inputs would be that good at charging due to the fluctuations but it seems really silly to buy the MPTT solar charger and have the battery charger cost more then the rest of the project combined. I saw this write up but it seems that the solar charging did not work all that well (https://www.hackster.io/fablabeu/esp826 … fun-982bc6).
If I am just posting a temp say ever 10min and sleeping the rest of the time what would be the best setup? Keep in mind it would need to report during the night as well but as it is for a pool it really only needs to run during the summer months.
Hi,
I’d rethink your idea entirely! First, solar powering your device is going to be a pain, and second, the measured temperature on the surface of the pool isn’t going to be really what you want anyway! At night it will be representative of the pool temp., but during a sunny day it will read quite a bit higher than the ‘real’ average pool temp.
What I did is insert a PVC ‘T’ in one of the filter return lines. I then glued a threaded adapter into the ‘T’, which I plugged with a threaded brass plug. I drilled out the back of the brass plug to a depth just short of passing all the way thru, and epoxied a Dallas DS1820 temp. sensor into the hole. I used a thermally conductive epoxy to ensure good thermal transfer between the brass and the sensor. This solution works like a charm, and I can check my pool (or spa) temperature from anywhere on the face of the earth! :dance:
The only downside to this approach is that the filter pump needs to be running, but that usually happens for a few hours each day, and the pool temp. changes pretty slowly. If it was a real issue, I’d probably write some code to run the pump for a couple of minutes prior to each temp reading!
john
What you describe is what I have setup on my pool =) This is for my father and while the top can be a bit warmer I am making the enclosure to dip down about 8in where the probe will be. For him I was trying to make a drop in and forget method so will just tinker around and see what I can do.