ESP32 Plant Logger

Logs temperature, humidity and moisture of plant soil using MicroPython.

Components

• Microcontroller: ESP-WROOM32 DEVKIT 1
• Temperature & humidity sensor: DHT20
• Moisture sensor: Geekus Soil Sensor
• Micro SD slot: 3.3V Mini TF
• Micro SD card: Any card, formatted to FAT32 without any partitions.

Pinout

Component	Pin Name	Pin #
SD Card	MISO	19
SD Card	MOSI	23
SD Card	SCK	18
SD Card	CS	5
DHT20	SCL	14
DHT20	SDA	13
Moisture	ADC	36
Built-in LED		2

Setup

Erase flash

esptool.py --chip esp32 erase_flash

Compile & install micropython firmware

Build micropython locally

# compile micropython
cd micropython/
make clean
make submodules
make BOARD=ESP32_GENERIC

# write firmware to device
esptool.py --chip esp32 -b 460800 --before default_reset --after hard_reset write_flash --flash_mode dio --flash_size 4MB --flash_freq 40m 0x1000 build-ESP32_GENERIC/bootloader/bootloader.bin 0x8000 build-ESP32_GENERIC/partition_table/partition-table.bin 0x10000 build-ESP32_GENERIC/micropython.bin

Copy code

Initial RTC clock:

mpremote rtc --set

Copy *.py files to device

mpremote fs cp src/*.py :

Usage

Add SD-card and reboot device. The LED will flicker every 30 seconds as data is collected.

License

MIT