Hi everyone,
An update about the I2C communication on my setup. I decided to use a twisted pairs wire (like phone cable or CAT5 cable) to connect the BMO compass and the MMA inclinometer from the roof of the tractor to the PCB V2. The total length of the cable is about 3 m. I used this document to draw the schematic : https://www.nxp.com/docs/en/application-note/AN10441.pdf.
I had to add two NMOS transistors (2N7002) and two 4.7k resistors to the PCB for 5V pullup. On the other side, I added two 4.7k resistors for 3.3V pullup and a 22µF capacitor to smoothen the sensors power supply.
I tried it for a few hours doing work in the field and the setup seems to work properly. I get MMA and BNO data continously.
Here is a schematic of my setup :
Some pictures :
An I2C extender like the P82B715 would be even more powerfull. It would allow to use even longer cables and would make the link even more reliable. It would be easier to have it included on the PCB though.