“ It has to be some electro-magnetic based communication instead of currents so the circuit has to be more complicated. I doubt it's done without using any kind

“ It has to be some electro-magnetic based communication instead of currents so the circuit has to be more complicated. I doubt it's done without using any kind of software but would be glad to hear otherwise.” You can do the whole thing in analog fairly easily. The hardest part would be to get the magnetic sensor integrated into the same chip, but I guess that’s been a solved problem for a while.