Software for my ATtiny88 based humidity sensor. The board is also some kind of development board to play around with the ATtiny88, but mainly focused on humidity.

The humidty and touch sensors are built on capacitive touch technology described in https://www.youtube.com/watch?v=BO3umH4Ht8o&t=547s

It consists basically of loading a capacitor and measuring the tics until the input is read as high.

The software works as a state machine and can do the following:

• measure humidity on humidity sensor and show if too humid/dry on 3 LEDs
• handle 3 touch button
• touch1/2/3 activates the display
• long press on touch2 sets the threshold humidity
• display shows humidity, humidity threshold, temperature and battery voltage

See the pcb folder for schematics.

brew install platformio avrdude
pyenv virtualenv 3.7.4 attiny88
pyenv local attiny88
pip install -r requirments.txt

Run the following to activate the necessary files. This command symlinks the files to the folder src/

./activate.py modules/humidityguard

Connect board with USBTinyISP to computer and run

make flash

Ensure tart serial console

make debug

• modules/common/def.h: IO definitions for the board and common functions
• modules/common/avr_print.*: Debug software to print to serial terminal