[sam028]

Hello,

Today I have, on a Revo board with:
- GPS on Receiver port
- telemetry (MinimOSD) on Flexi port
- S.Bus on Main port

If I want to add an external mag the single option is to forget about sbus and have something like:
- PPM+GPS on Receiver port
- I2C on Flexi port
- Telemetry on Main port

Am I right, no magic trick to keep S.Bus in this case?

Thanks,
Sam

[f5soh]

You can consider a Naza GPS connected to the receiver port adding a external magnetometer without additional port used.
So GPS and Mag data using the same serial connection.

[TheOtherCliff]

You can also buy an SBus <-> PPM converter for about $10, but DJI/Naza GPS is probably better.

Also, if it is a large quad (say 500mm like I have) and you are very careful about wiring, you can fly with on board mag that is built in the Revo.

(edit) To be complete, you could also replace the FC with a Sparky2 (about USD $30 to $46 depending on quality and where you buy it) which can handle all of those directly and at once because it has a separate I2CPort for the mag and the SBus is put on the RcvrPort, not MainPort.  ...but some GPS/mags have mag issues that require adding a pair of pullup resistors to make the mag signal more reliable.

[sam028]

Thanks for the the replies, the NAZA GPS seems to be the best option.

@TheOtherCliff: it's a 250 so the internal mag is too close from the motors (and just above a 4 in 1 ESC and a RunCam Split PCB) so it's a bit too much for it.

[anthropo]

but some GPS/mags have mag issues that require adding a pair of pullup resistors to make the mag signal more reliable.

Can you explian that please ? where do you need to add pullup resistors ? what value do they need ? (I have a revolution board)

Thank you

[anthropo]

Just have found this post https://forum.librepilot.org/index.php?topic=1110.msg15398#msg15398

Forget my question and Thank you

[TheOtherCliff]

https://forum.librepilot.org/index.php?topic=3325.msg22786;topicseen#msg22786

The cheap clones sometimes have issues and the fix is to install a pair of pullup (to 3.3v, not 5v) resistors (say 3k to 5k) on both SCL and SDA lines in the I2C cable.  Best place is to just add the resistors inside the GPS shell.  The GPS has regulated 3.3v on the circuit board.

Note the recommendation of 3k to 5k, not the 10k you see in the schematic.