Capacitive Soil Moisture Sensor

[Ron]

Hi everyone,

I am happy to share my very first PCB design project with you. It is a capacitive soil moisture sensor using an ATmega328P and NRF24L01+.
The capacitance is measured as commonly done through a low pass filter using the ATmega PWM instead of a NE555.

I am not a professional in the area of microelectronics and pcb design and have thought me most of the things myself. This is also why I already have a ton of ideas for future improvements on the design with the switch to a NRF52 being on top. Still I am quite satisfied with my results so far. The pcb is tested and working (despite the fact that I soldered a wrong value capacitor and forgot the capacitor for the ftdi connector, which is already fixed). You can see example measurements on a plot below.
I have made all source files available on the corresponding GitHub repository.

I am happy to hear your thoughts and maybe some tips and remarks.

Cheers!
Ron