CanGrow - An OpenSource grow controller firmware for ESP8266 / ESP32

CanGrow is a firmware for ESP micro controllers for automation and monitoring of all plant needs. It can be understood as a lightweight standalone alternative to HomeAssistant for plant growing systems.

🌱 Features

• Support for ESP8266 and ESP32 microcontrollers
• Everything runs on the ESP microcontroller itself, no need for HomeAssistant
• Lightweight WebUI with integrated Dashboard
• Dashboard with Gauges and simple Linechart
• Data Logging into builtin flash with LittleFS for the line chart to see past 32 hours
• Free and flexible configuration of outputs (GPIO, HTTP, I2C) and sensors (builtin ADC, I2C modules)
• Sensor values offered by JSON API /api/sensor/
• Platform independent - Build your own hardware and drive it with the CanGrow firmware
• Set different light times for Vegetation and Bloom phase
• Simple watering plans, based on time interval and/or sensor value
• Control fan outputs depending on sensor values
• Support for I2C RTCs to keep the time when NTP is not available
• Support for I2C DAC GP8402 as output to control 0-10V devices like Grow lights, Fans, etc
• Support for Wifi Plugs as output by sending simple HTTP requests
• OTA update via the WebUI
• Access Point creation as Failsafe mode when Wifi not available (see serial monitor)
• Configuration saved as JSON within LittleFS for easy backup & restore

🤖 Supported Micro Controllers

Name	FQBN	I2C GPIO	Notes
ESP8266 D1 Mini	esp8266:esp8266:d1_mini_clone	SCL: 5 SDA: 4	The default build target for the moment.
ESP32 D1 Mini (WROOM)	esp32:esp32:d1_mini32	SCL: 22 SDA: 21	NodeMCU should work as well with this
ESP32-C3 Supermini (Makergo)	esp32:esp32:makergo_c3_supermini	SCL: 9 SDA: 8	Works with cheap nologo ones as well
ESP32-S2 Mini (Lolin)	esp32:esp32:lolin_s2_mini	SCL: 35 SDA: 33	Works with cheap nologo ones as well, Crashes when serial monitor is active and LittleFS writes
⬇️untested⬇️	⬇️untested⬇️	⬇️untested⬇️	⬇️untested⬇️
ESP8266 NodeMCU	esp8266:esp8266:generic	SCL: 5 SDA: 4	For all ESP8266 Dev boards
ESP32 NodeMCU (WROOM)	esp32:esp32:esp32	SCL: 22 SDA: 21	For all ESP32 WROOM Dev boards
ESP32-C3 Dev board	esp32:esp32:esp32c3	SCL: 9 SDA: 8	For all ESP32-C3 Dev boards
ESP32-S2 Dev board	esp32:esp32:esp32s2	SCL: 35 SDA: 33	For all ESP32-S2 WROOM Dev boards

🎛️ Supported Boards

Name	FQBN	I2C GPIO	Notes
CanGrow 12V PCB	esp8266:esp8266:d1_mini_clone	SCL: 5 SDA: 4	Outputs are inverted (not FAN2) Output GPIOs: - LED: 12 - FAN1: 14 - FAN2: 0 (NOT inverted) - PUMP: 16 Onboard analog sensor GPIOs: - Those GPIOs are needed to "activate" the analog sensors onboard (<= PCB v0.6.1) - Analog soilmoisture: 13 - Analog waterlevel: 15
ESP12F Relay X4	esp8266:esp8266:espino	SCL: 5 SDA: 4	Ensure GPIO PWM is set to No for the relay Outputs Relay GPIOs: - Relay 1: 16 - Relay 2: 14 - Relay 3: 12 - Relay 4: 13
ESP32 Relay X8	esp32:esp32:esp32	SCL: 22 SDA: 21	Ensure GPIO PWM is set to No for the relay Outputs Relay GPIOs: - Relay 1: 32 - Relay 2: 33 - Relay 3: 25 - Relay 4: 26 - Relay 5: 27 - Relay 6: 14 - Relay 7: 12 - Relay 8: 13

💡 Supported Outputs

Output name	Notes
GPIO Pins	On/Off, PWM support, DAC tbd.
I2C DAC modules	GP8402 (0-10V), MCP4725 (0-3.3V)
HTTP requests	- Tasmota / Shelly Wifi plugs - whatever REST API

🌡️ Supported Sensors

Sensor name	Readings	Notes
GPIO ADC	internal ADC GPIO, can be converted
BME280	Temperature, Humidity, Preassure
BME680	Temperature, Humidity, Preassure, Gas resistance	slow sensor, reading data takes up to 1,5s
SHT3x	Temperature, Humidity
MLX90614	Temperature
TCS34725	Color, Lux, Light temperature	slow sensor, reading data takes up to 2s
ADS1115	external 16 bit ADC
ADS1015	external 12 bit ADC
Chirp	Soilmoisture, Temperature
CCS811	eCO2 ppm, TVOC
ENS16x	eCO2 ppm, TVOC, AQI UBA
AHT1x/AHT2x	Temperature, Humidity
SCD4x	CO2 ppm, Temperature, Humidity	slow sensor, data refreshes every 3-5s (reading is fast)

💾 Installation

You find in the Releases section of the Git repository pre-compiled binaries which you can upload directly.
The WLED project made a very good instruction how to upload a .bin File to the ESP. Please have a look here: https://kno.wled.ge/basics/install-binary/#flashing-method-2-esptool

Alternatively you can also build and upload the code by your own. Please have a look into the Section Build Environment

If you are interested in a mostly working and bleeding edge development release, check out the pre-built snapshot binaries on pub.la10cy.net

🔌 Setup

After uploading the firmware to the ESP, you might want to perform a factory reset of the firmware.

Factory reset step-by-step

1. Power on the ESP
2. The internal LED flashes 3 times
3. While the LED flashes, bridge the pins as shown in the table
4. Release after holding for three seconds
5. The internal LED will flash fast and the ESP restarts
6. Factory reset done, to check, have a look into the serial console

ESP variant	GPIO	bridge to
ESP8266	D4 (2)	GND
ESP32 WROOM	2	+3.3V
ESP32-C3	8	GND
ESP32-S2	15	+3.3V

CanGrow creates a new Wifi by default

SSID	Password
CanGrow-unconfigured	letitgrow!

Connect to it and open the page http://192.168.4.20

📷 Screenshots

🔨 Build environment

The helper script cangrow.sh is written for a Debian 13 system.

To install all dependencies you need for building the firmware, run the cangrow.sh setup:

$ ./cangrow.sh help
./cangrow.sh [setup|build|upload|webupload|monitor]
setup: setup build environment, download arduino-cli, install all dependencies for arduino ide
build: build firmware binary. will be saved into build/
upload: upload firmware by serial connection /dev/ttyUSB0
webupload: upload firmware with webupload to 192.168.4.20
monitor: serial monitor /dev/ttyUSB0

# Install all dependencies for build environment
$ ./cangrow.sh setup

The script installs arduino-cli to ~/.local/bin/arduino-cli.

⚙️ Compile

# compile and output to build/CanGrow_v0.2...bin
# Default Target is ESP8266 D1 Mini
$ ./cangrow.sh build

# Compile for ESP32 D1 Mini
$ export BOARD="esp32:esp32:d1_mini32"
$ ./cangrow.sh build

# Build and upload by serial USB connection for ESP32 (WROOM generic)
$ export BOARD="esp32:esp32:esp32"
$ ./cangrow.sh upload

# Build and webupload to IP
$ export IP="192.168.4.69"
$ ./cangrow.sh build # need to make .bin first
$ ./cangrow.sh webupload # upload

# listen to serial monitor on /dev/ttyUSB2
$ export TTY="/dev/ttyUSB2"
./cangrow.sh monitor

♾️ Compile with Arduino IDE

You can also avoid using ./cangrow.sh setup , for example if you are on a different Linux distribution or Operating System, like Windows or OSX.

For this, you just have to copy the content of the libraries/ directory to your Arduino libraries Folder. This would be on

• Windows: My Documents\Arduino\libraries\
• Mac OSX: ~/Documents/Arduino/libraries/
• Linux: ~/Arduino/libraries/

After this, you just have to ensure, you have the correct Arduino Core installed for your ESP you want to compile CanGrow for.
How to add the ESP Arduino Cores is well described in this Instructables

🦭 Podman / Docker build container

Just do a compose up with the container engine of your favor to build all supported firmware binaries

# With podman
$ podman-compose up ; podman-compose down

# With Docker
$ docker compose up ; docker compose down

To only build for one ESP platform (e.g. the ESP32 NodeMCU), just put the (supported) FQBN into the BOARDS environment variable:

$ echo 'BOARDS=esp32:esp32:esp32' > boards.env
$ podman-compose up ; podman-compose down
# just remove the file to build for all platforms again
$ rm boards.env

To update the build environment just run

# re-generate the whole container image (safest method, takes longer)
$ podman-compose build

# just re-run 'cangrow.sh setup' within the actual image before build
$ echo 'UPDATEBUILDENV=1' > updatebuildenv.env
$ podman-compose up ; podman-compose down
# dont forget to remove it, if you dont need an update afterwards 
$ rm updatebuildenv.env

🪔 Geany IDE

I wrote this project using Geany IDE. . The Geany Projectfile is also included, just run

$ geany CanGrow.geany

F8 compiles the project, F9 uploads firmware to /dev/ttyUSB0. You can change these settings for .ino and .h files in Project -> Settings -> Create/Make.

📐 Development

Please have a look into the Project Board to see which Issues are open or already in work.

If you want to open an issue, feel free to do so on the public Codeborg Mirror or Github Repo (empty).

📜 License

Copyright (C) 2025  DeltaLima
This program 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.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.