Pool Temperature Monitor Mollifies Fortunate But Frustrated Children

Who needs the city pool when you can party in the private pool over at Grandma and Grandpa’s house? No need to wait until Memorial Day weekend when it hits 90° F in the first week of May. But how can you placate grandchildren who want to know each and every day if it’s finally time to go swimming, and the pool itself is miles away? Although grandparents probably love to hear from you more often there’s no need to bother them with hourly phone calls. You just have to build a floating, remote pool temperature monitor which broadcasts every 30 minutes to an Adafruit MagTag sitting at kid’s eye level on the refrigerator.

Between the cost of commercial pool temperature monitors and all the reviews that mention iffy Wi-Fi connections, it sounds like [Blake] is better off rolling his own solution. Inside the floating part is an ESP32, a DS18B temperature sensor, and a 18650 cell. Most of the body is PVC, except for the 3D-printed torus that holds some foam for buoyancy. A handful of BBs in the bottom keep the thing pointed upright. For now, it shows the water temperature, but [Blake]’s ultimate goal is to show the air temperature as well.

Maybe it’s still too cold to swim, but the sun shines brightly most days. Why not harness its energy to heat up the water?

25 thoughts on “Pool Temperature Monitor Mollifies Fortunate But Frustrated Children

          1. WTF does UL 1081 have to do with the device per the OT? Did not see anything about pumps or chlorinating equipment.

            Somewhere within the first two or three pages of every IEC and ANSI standard is the scope statement(s). Ya might wanna read them.

          2. Brian,

            “At least give me pH and automated dosing chlorine ;)”

            That’s the line I was replying to. The organization of comments on this site can make it difficult to trace replies. I was not replying to the original article. If I was I would have said UL1563 which covers most pool / spa related equipment that is either plugged in, permanently connected or convertible between the two.

            Your reply was nasty. Please reread what you wrote and reconsider writing in that manner so as to not propagate nastiness.

    1. Don’t know about you, but our local public pool in the SF Bay area has been open since the initial lockdown was lifted last summer. I swam a few days there over the winter. Now that our local club pool is open, I’ve been been swimming there. My backyard pool is still too cold and green :-( to swim in.

      Someday I’m going to build a similar wifi thermometer like this project, but I’ll be posting the temp to my weather station web page rather than a LCD. Also, I don’t see the point of it floating. I’ll fix it to a piece of rope so it doesn’t get sucked toward the filter inlet when it runs.

  1. I have a favorite swimming hole in a remote location in the woods 50 miles away, I wonder alot about how I could monitor this. The swimming season js short there, so I’d like to know to go as much as I can.

  2. Amazon has 2 wireless (not wifi) units under $33 USD:
    Inkbird IBS-P01R Wireless Pool Thermometer Floating Easy Read, Remote Pool Thermometer for Swimming Pool, Bath Water, and Hot Tubs.
    Cangfort Wireless Pool Thermometer – Digital Floating Pool and Thermometer

    i had one like the latter a few years ago, had planned to packet sniff the signal to reverse engineer…. someone broke the sensor unit in the pool so i gave up on that project. They used a large hex nut as a counterweight … yours looks more durable.

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