Need continuous Telemetry data

For my application I need to monitor the telemetry data stream from a Mini 3.5. I am not using a telemetry link, I just need the data on board, so there is no telemetry transmitter or GCS.

Is there a setting that activates the data stream? Is there a ‘heart beat’ protocol that can be fed into the telemetry input?


@Crane so your plan is to make a companion computer or similar that would
receive telemetry feed from autopilot. You need to request MAVLink feed
when system starts. Really similar like what we do in jD-IOBoard or MinimOSD.
Both hook up on additional serial ports on pixhawk and when they reboot, if
they don’t see needed values coming from that port, software will initiate
MAVLink rates command and request wanted parameters with wanted frequency.

Thanks for the response.

Yes, I am using the APM3.5 with an MSP430G2553. Where can I educate myself on the MAV protocol?

There is similar post going on with another user. You can look that here:

I have listed several good starting points for MAVLink on that post for this user.

That’s a good start. I’ll set up a test system and see how far I get.

Will probably have some specific questions once it’s operating.

Thanks again.

OK, I have a test set up and my MSP430 receives and parses the data stream from the APM 3.x.

I can select packets by command number. All works great, but I can’t decipher the packet. It appears that each command has a format (Schema) associated with it, Is there a clear specification for these formats?


Try this—).

That works.



Good information, but so far I can’t match up my results with the formats.

For heartbeat from the APM 3.5 I get (hexadecimal):


How do I read that? Is the packet order reversed?


Thanks for the help.

I’ve documented my learning experience here:

for anyone sharing the interest.