Transfer data between coils

[fsoender]

Im looking into designing a wireless data transmission using two coils.
Tx coil will send a 8 bit data to the Rx coil that sends it to the PC thru USART.

I want to read multiple temperature sensors thru a steel wall. I will be using a Atmega128.

Transmit package:

XX XXXX XX = 8 bits
2 bit Address / 4 bit Data / 2 bit Checksum

I know that this kind of system is in use, do anyone know how to design this or have an example to help me on the way?

 

[FvM]

You should get an idea of feasible carrier frequency and attenuation through the stell wall.

Then decide about a suitable modulation method.

 

[fsoender]

Ok, thanks.
Have you ever seen any schematics for similar project?
The frequency have to be low, I know they are in the ELF band.