Plant moisture sensor - I give up...

  • I have now tried to build a plant moisture sensor that will have a battery life longer than 2 month and I have to confess, I can't do it.

    I get either 1023 or something like 54 (always two static values and yes I'm using a analog moist sensor).

    I have seen this and it looks like my thoughts

    Since we only have two plants in our house It feels like it would be simpler to buy a already made sensor and then connect it to MySensors gateway.

    Most of the ready made are using bluetooth to communicate so it would be possible to use a bluetooth arduino module to communicate (I you know how to read the sensor)

    My ide was to buy something like this:
    Plant Sensor on Aliexpress
    Strange thing on Ebay that could be adapted
    Parrot Flower Power - that actually is a lot cheaper in Sweden where you can buy it for like $30

    and either build a Bluetooth MySensor that can talk to the two bluetooth (i.e decompile the android app to get how the API works)
    or attaching something to the soil sensor (with it own battery) after removing the summer

    Has anyone tried this? or done something similar?
    There are several other plant sensors around and the above is just an example at Wife Friendly sensors that maybe could be adapted to MySensors.

  • Hero Member

    The Xiaomi Mi Flora seems interesting. Hard to build a similar device at that price that would last 1 year on battery (It even beats my sensebender soil moisture).

    There is something on GitHub for it. Looks like some kind of Phyton script library (might be intended for Home Assistant).

  • Hardware Contributor


    It depends of what plant, and soil type you want to monitor.

    • I don't have flower power, so i have no xp, but this is an indoor product, i don't know about which soil types and its precision, and no idea about it's lifetime. But i think it's a nice product for indoor.
    • the xiaomi : it's crappy as you wish 😉 I have bought one as i was curious to see what you get for this price. I own professional tools. Precision is not good and often out of range! And i suspect it doesn't work well in all soil types..and even a level trigger is not good. Wet the pot soil more than enough and it always tells "not enough water"! 😆
    • the small module : there are multiple forms, and multiple quality..capacitive or not..and even if using a capacitive sensor does not mean it will be more precise or robust, it depends of the circuit. For its lifetime, it will depends on the soil PH etc..and also the soil granularity etc for the precision..
      About battery you would need to cut off the sensor part.
      A note : powering off the sensor, won't completely prevent oxydization. There is always a mini reaction in soil.
      So it depends of what you want to do. There are these links which are nice for you maybe:

    And as a work in progress, I have made few design like a koubachi/flowerpower and professional soil moisture 🙂 not ready to release yet.. Professional tools are very expensive. Perhaps a lot too much sometimes. But the quality and precision is excellent for labs etc..even in different soils. And they don't want something which only triggers and says "water please".

  • @scalz

    Thanks for the advise and your good points.

    But as you can see we have two living plants (in a 230m2 house 🙂 ) so It's just so we don't need to buy new plants every other week.
    It probably wood be enough to use the Xi Plant as it is with the mobile but I want to have the alarm that tells me "Hey give me some water"

    I can say that under the 3 weeks I tested to build my own sensor for this two plants died on my desk 🙂 .

    As you can imagine nor my wife or me are "plant people" 🙂

  • Hardware Contributor

    only what i can tell you is : the xiaomi may look cute, but it doesn't work well. and for instance, for orchidea it does not work at all on my side. Like i said, after watering more than enough, it still says it needs water! Ec out of range. If you want an ambiant air temp and lux sensor then it seems to work 😆 You can try, it does not cost so much so..perhaps you'll be lucky for some plants 😉

  • @scalz said:

    s not cost so much so..perh

    Or maybe the plants would be lucky to get to survive 🙂
    I'll test and see what I can do with a Bluetooth sensor, it's worth a try

  • Water is heavy no? Use a weight sensor. Get weight after a fresh watering and run comparison. I guess it would depend on the size of your house plants.

  • Have you seen this thread?

    Just finished building one of these and it works a treat, going to test it for a while to see how long the battery lasts with the solar power.

  • @mrwomble

    I have seen it and it's nice. Live in Sweden where the sun turn of at around 18:00 (6pm) so we need batteries 🙂
    Joke aside my are intended to be used for the two plants we have indoors.