$12 Plant Bot is an ESP32-C3 soil sensor and pump driver for fully automated indoor plant care
$12 Plant Bot is an ESP32-C3 soil sensor and pump driver for fully automated indoor plant care
The Plant Bot is an open-source, Internet-enabled plant monitor powered by the ESP32-C3 microcontroller and integrating a corrosion-resistant capacitive
At home I use an "automated indoor plant care" device of my own making with about $3 of parts (including a capacitive sensor) plus a water pump on a jar full of water and some hose.
Because it uses an ATTiny45 (I had plans to move to a more modern microcontroller but couldn't be arsed) rather than an ESP32, it's not "internet enabled".
I specifically chose a microcontroller which only used about 2 micro Amperes in sleep mode and has a broad range of functional input voltage, so that it can run directly of 3x AAA batteries, which only have to be changed about every 10 months.
I would say that "doesn't need to be plugged to an external power source" and "batteries last ages" are probably more important requirements that "internet enable" for something whose only purpose is to automatically keep the humidity of a vase above a certain value and to me this Plant Bot just seems overengineered and trading important things for frills.
This kind of stuff is really just an Advanced Arduino project.
Do you have some designs posted someplace? I have Arduino experience but I don't know how to build anything for $3.
I don't have that design posted anywhere. Here's the circuit diagram in image format:
I don't use Arduino boards but rather the microcontroller chips directly, which turns out to be pretty simple to do (here's some videos on doing Arduino stuff that way).
Because I'm using discrete components (mostly DIP so that they can go into a perfboard but also some cheap SMD MOSFETs because low power SMD MOSFETs go for 2 cents each and work fine for just driving a small water pump whilst all the DIP MOSFETs are power MOSFETS, so much more expensive and way over spec for the kind of currents a small water pump pulls) so it all adds up to very little cost, plus I made a board design for it and had 20x of that done by some cheap chinese PCB maker so even the board ends up even cheaper than a perfboard.
Doing the whole thing around an Arduino board, even a cheap Arduino Micro is much more expensive, way over-spec for an automated watering device plus those boards tend to eat up lots of power when in sleep mode so the batteries wouldn't last long if the circuit was built around such a board - if you look at the diagram, all the paths from VCC to GND either go via the microcontroler (like how SIGNAL- and SIGNAL+ drive both sides of a two color bi-directional LED) or have a control MOSFET that blocks by default when the micro-controller doesn't send any signal (like SENS_CTRL).
The $3 bucks are a rough estimate but I wouldn't be surprised if it's an overestimate. It really depends on the price of the capacitive sensor you're using (I just get mine from Aliexpress) as that might actually be more expensive than the rest. However do note that the price of the water pump was not included and that adds maybe another 2 bucks.
EDIT: For some weird reason I kept mentioning "diode" when talking about MOSFET transistors, so I corrected that.
But muh Home Assistant needs them fancy watering features & humidity data! :D
(I don't actually have it set up, my watering has no wireless connectivity either, but does have a battery and solar panels)
I can tell you already it's garbage.
From the picture, the edges of the PCB are exposed, which means it's going to corrode in the moist soil. Avoid.
Use a capacitive sensor, and make sure it's one that's fully encapsulated and sealed at the area where it enters the soil.
..integrating a corrosion-resistant capacitive moisture soil sensor
The first line states that it IS capacitive and corrosion resistant.
They are saying the circuit (being capacitive) doesn't have the electrolysis effects of the normal resistive circuit. That's all. Look at the PCB; I work with these things -- You HAVE to seal the edges with solder resist as well, to seal the system.
I've somehow been able to keep a baby dragonfruit cactus alive for a little while now. I feel like I'd kill it using this.
I imagine you configure the parameters that trigger it to water, and how much. Is there more you pay attention to than soil moisture and how much water you add when taking care of it? (Like how it looks, or whether it's flowering/fruiting if it does those things)
I know little about plant care (I killed my snake plant, Fettucine 🥲), I'm genuinely curious :)
I think the big problem is that the amount of watering drastically changes throughout the year. In the winter, it only should be watered like once a month, and in the summer like once a week, with gradual steps in-between.
I'm sure there is a way to program it, but I feel like I'd get the curves wrong or some shit.
I'd still find a way to kill it.
I just ordered one and I don't even have a house plant!
I have a serious esp32 problem.
Love the idea, but capacitative sensors like this do degrade somewhat quickly. If you bump them, your calibration curve is no longer valid. Putting all of your electronics a centimeter from the soil, which will also be watered is also a mistake.
An esp32 dev board, a motor board and an unpluggable replaceable sensor makes so much more sense from a practical standpoint.