DIY fertilizer mixer and plant watering machine
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Thomas Buck 3a80536871 add support for dark-mode in web ui 2 months ago
include in fullauto mode run pumps as a last step to really empty the lines as far as possible. 3 months ago
influx add influx calibration script, readme note. 10 months ago
lib first commit 1 year ago
src add support for dark-mode in web ui 2 months ago
test first commit 1 year ago
.gitignore various fixes. return to init screen on idle. missing fillnwater case. added some influx export scripts for testing. prepared for automation menu. 1 year ago
COPYING Added GPLv3 license. Extended Readme. 1 year ago add influx calibration script, readme note. 10 months ago
platformio.ini revert back to older esp32 platform version. had issues getting a wifi ip. 5 months ago


Firmware for automatic plant-watering machine, with web interface, LCD and keypad support, using two MCUs communicating via I2C.

For more please also take a look at Giess-o-mat on my website.

Quick Start

If you don’t already have it, get PlatformIO.

Before building for an ESP32 or ESP8266 target, execute the following commands, replacing “…” with the values of your network, so you can connect to WiFi.

echo '#define WIFI_SSID "..."' > include/wifi.h
echo '#define WIFI_PW "..."' >> include/wifi.h

Then simply run the build for all supported configurations with platformio.

pio run

You can of course also use pio to flash your targets.


In general, the project consists of two parts, the controller and the ui. They both communicate via I2C. In my own setup, I’m running the controller on an ESP32, and the UI on an Arduino Nano. It is also possible to run the controller with an ESP8266 or an Arduino instead. You can also run both on one board, but this was up to now only used on Arduino for testing purposes.

Of course you need to take care of voltage levels when connecting different boards. I’m running the UI with 5V and the ESP32 is using 3.3V. For safety reasons I added a bi-directional I2C level converter between them.


The following targets are defined for this project.

Name Board Function Tested Usable
esp8266_main ESP8266 Controller No ?
esp32_main ESP32 Controller Yes Yes
arduino_ui Arduino Pro UI Yes Yes
arduino_test Arduino Pro Both Yes No
leonardo_main Arduino Leonardo Controller Yes Yes
leonardo_test Arduino Leonardo Both Yes No

The “unusable” test targets were only used for easier development. They do not have enough GPIOs for all functionality!

ESP8266 should work in theory, as long as the board has enough GPIOs, but I have not tested it.

See ‘include/config_pins.h’ for the GPIO number definitions for the different configurations. Some other options can be set in ‘include/config.h’.

When an ESP is used, a webinterface and OTA updater will be included as well. For the ESP32, you can upload a new firmware using a webbrowser. Simply use the link on the main page of the web ui, then upload the ‘.pio/build/esp32_main/firmware.bin’ file from the project directory after building.

Writing events to InfluxDB is also supported. Configure the server and database in ‘include/config.h’. It will store the valve-open duration (in seconds) with the following measurement types:


Fertilizer shows each time a fertilizer pump has been running. Plant shows when multiple plants have been watered at the same time. Additionally, calibrated_filling can be used to determine the inlet flowrate and calibrated_watering can be used to determine each outlet flowrate, as long as the tank size is known.


Copyright (c) 2021 Thomas Buck <>

Giess-o-mat is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Giess-o-mat is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Giess-o-mat.  If not, see <>.