In this project I develop a small, battery-powered soil moisture sensor using the ESP32 with a status indicator and logging to the cloud!
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Read the project logs for all the detailed information 😊, or view the project on GitHub:
https://github.com/maakbaas/esp32-soil-moisture-sensor/tree/master
The final assembled product in a 3D printed enclosure:
To maximize battery life a bistable flip-dot status indicator is used to show if the plant needs water:
The sensor has enough resolution to measure differences in water levels in the required range:
Case.zipSTL files for the 3D printed casex-zip-compressed - 118.58 kB - 04/18/2021 at 17:12 |
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Gerber.zipGerber files for the PCBx-zip-compressed - 38.24 kB - 04/04/2021 at 14:29 |
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Schematic.pngThe schematic for the PCBPortable Network Graphics (PNG) - 34.00 kB - 04/04/2021 at 14:14 |
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After publication on the front page, I got several requests for the design files. I have posted them to GitHub here:
https://github.com/maakbaas/esp32-soil-moisture-sensor/tree/master
In this final post I will dive into the connectivity and WiFi functions for the ESP32 soil moisture sensor. The goal is to be able to log the sensor data to the cloud and pull it into a home automation system. The data will first be buffered locally, and then pushed to the cloud in a batch. This is needed because WiFi is significantly more power hungry compared to other activity. With this approach the device should theoretically have a battery life of two years.
In this post and the next I will present the software that is running on my ESP32 soil moisture sensor. In this initial version of the software I focus on the parts that allow the sensor to work in standalone mode. This includes the push button, the status indicator and the actual sensor implementation. In the next and final post I will dive into the connectivity and WiFi functions.
After receiving the circuit boards for my soil moisture sensor, the biggest question was whether the actual sensor would work. It seems like dark magic, how a simple copper pad, connected to an ESP32 without any additional circuitry could turn into a moisture sensor. Therefore, the first thing I did after building the boards is to see how well this would work.
Recently we bought some new plants to fill up some of the space after we moved to a larger house. I am not the best plant owner, and need to be reminded when to water these new housemates. Roughly at the same time, I found a cool new component, that can switch from red to green, and only requires current when switching. This makes it a great status indicator for battery-powered products. One plus one is two, and this gave me the idea to build a soil moisuture sensor using this status indicator.
Awesome project! I want to try and recreate your project and create some of my own. I'm wanting to order some PCBs based on your gerber files, but I'm still a bit of a noob & newish to custom hardware. Do you mind sharing some of the information when you ordered the PCBs? I'm curious on the overall size dimensions, PCB layers, etc. Thanks in advance!
Hi, thanks for your message. Normally, if you upload the Gerber files, this information is extracted automatically. The PCB is a 2 layer PCB, roughly 107 by 23mm.
Maakbaas
Rex Garland
Bud Bennett
Debasish Dutta
AG March
Hello. Great project - I think I'm going to make some of them. Any chance you'd put the code for this on your github?