Hi, I'm building a probe that needs to communicate through the ground, all the usual frequencies would not reach any lower than a few inches to about 1 ft in dry ground. I'm usually between 3 to 6 ft deep sometimes in clay.
I'm already generating signal to locate the probe and receive it fine at 512 Hz and 32.8 kHz, stepping this project further I want the probe to send pressure and a few Analog reading to a receiver above the ground.
So far I'm using Arduino Micro, Fet driver and coil antenna.
Beeing a total noob in data transfer, I'm looking for an existing protocol that can be useable at a extremely low frequency. I will need to build both antennas and probably some analog to digital converter, filter, etc
So if someone have seen a project like this, know good reading for getting me started I would appreciate some help