ESP32 IDF Plant Watering System in Rust 🌱

Welcome to my little corner of the internet, where technology meets nature. I'm excited to introduce you to my ESP32 Plant Watering System, a project that combines my love for plants and coding. This DIY solution, crafted with the Rust programming language, aims to make plant care a breeze. My goal was to find a way to keep my plants healthy and happy while learning embedded Rust.

Key Features:

• 🌡️ Temperature, Humidity, and Moisture Sensing: Precise monitoring of plant's environment is ensured, allowing for the ideal conditions for growth.
• 📡 MQTT Client: Seamless connection and communication with other IoT devices are enabled, enhancing the system's overall flexibility and integration capabilities.
• 🔔 Discord Notifications: Share plants' status through Discord notifications.
• 🌐 OTA (Over-The-Air) Updates: Effortless system updates where the microcontroller is installed in hard-to-reach areas.
• ⏰ Scheduler: Intelligent watering schedules are planned, automating the process based on your plants' specific needs and environmental conditions.
• 💧 Valve Control: Automated management of water flow to the plants is ensured, conserving water and guaranteeing optimal hydration for every plant.
• 🔐 Secure Boot: Security is prioritized with a RSA signed secure boot process, guaranteeing the integrity of the system and data.

Flash image

Note

otadata partition erase is needed if ota partition bit is changed from default during operation.

espflash erase-parts otadata --partition-table partitions.csv
espflash flash  target/xtensa-esp32-espidf/release/esp-termo --monitor --partition-table partitions.csv

Flash signed image

Note

Signed image is necessary to enable secure boot and secure OTA updates, since it contains the root of trust.

Important

First, previous espflash flashing step need to be performed to add the bootloader to the chip. The esptool.py utility is designed for flashing the application partition only.

esptool.py  --chip esp32 elf2image --secure-pad-v2  target/xtensa-esp32-espidf/release/esp-termo

espsecure.py sign_data target/xtensa-esp32-espidf/release/esp-termo.bin  --version 2 --keyfile certs/secure_boot_signing_key.pem

esptool.py --chip esp32 -p /dev/tty.usbserial-0001  -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x10000 target/xtensa-esp32-espidf/release/esp-termo.bin

OTA

Build OTA image

espflash save-image --chip esp32 target/xtensa-esp32-espidf/release/esp-termo image/new.bin

Sign OTA image

espsecure.py images/new.bin --version 2 --keyfile certs/secure_boot_signing_key.pem --output serve/public/signed_new.bin image/new.bin

run basic image endpoint

cd serve/ && node serve.js

MQTT

Start MQTT broker

podman run -d --name emqx -p 1883:1883 -p 8083:8083 -p 8084:8084 -p 8883:8883 -p 18083:18083 emqx/emqx

Certificate

Generate certificate

openssl req -x509 -sha256 -days 356  -nodes  -newkey rsa:2048  -subj "/CN=alabaster.local"  -keyout key.pem -out cert.pem
echo -e "\0" >> test

Note Ending NUL character is needed for the esp-tls lib can read the whole cert file Add ASCII \0 character to end of cert.pem file via vim CTRL+V, 000

Add certificate to the MQTT server

In case of emqx: Follow instructions

Moisture sensor

The one I have is cheapo version so it need 5V for it's timer chip to work correctly.

Info is from this beautiful human being testing a bunch of cr@py sensors Video link

Sensor code greatly inspired by this Repo