X10+v2 and ELRS

[flyingw]

Hello Jim,

It had been a long time and I hope you and your family are well.

I have been working with a new ELRS system.  I'm using a RadioMaster TX15 transmitter and several RadioMaster receivers.  I got an 8-channel ER8GV receiver that I want to put into my sailplane that currently has an RFU and X10+v1.

To begin I configured an X10+v2 to take SBUS as its input.

Then I configured one of the PWM servo outputs on the ER8GV receiver to be a serial port and to output SBUS.  I connected it all up and powered on and it worked.

The X10+v2 green led flickered about three times per second.

I got feedback from the RCGroups ELRS forum that the SBUS errors are there because ELRS periodically sends back telemetry packets in time slots normally occupied by control packets.  My system's overall packet rate is 100Hz for 10ms frames and my telemetry ratio is 1:32.  That means it sends about three telemetry packets every second.  That could explain the three led flickers pre second.

My ELRS frame rate is set to 10ms and the receiver's PWM outputs are set to 50Hz.  The ELRS system therefore sends every other control packet to the PWM outputs.

The setup and servos seem to work, so I plan to try it out at the airfield soon.

Can you think of any reason I shouldn't fly it?

Thanks,

Paul

p.s.  Will your proposed X10+v3 take CRSF as an input?

[XPS]

Well, you are losing data, but at 100Hz it probably doesn't matter.

The X10+ V3 will support several new protocols including CRSF.

[flyingw]

Thanks Jim,

I agree that losing a small amount of data 100Hz may not matter for sport flying, but since the non-standard SBUS prevents the X10 from setting the failsafe positions I can't use it.  That's why the news about the X10+v3 supporting CRSF is encouraging.

I am learning about ELRS radios and receivers now and found a significant problem with the currently available receiver that have PWM servo outputs.

When you power up the receiver (with servos connected), the servos move un-commanded to a position about one half of their throw in random directions.  A few seconds later the transmitter and receiver engage, and then the servos move to their center and ready positions.

This problem even manifested itself on one of my planes such that the prop spins before the receiver and transmitter engage properly - I do not like that.

I just tested the XPS system with an XPS-J1 module and Nano receiver. It does the same thing: The servos move a little bit when I connect the battery to the receiver. But the Nano boots up so fast, maybe half a second for the servos to snap to their ready positions.

And, I repeated the test with an old Futaba 72MHz transmitter and receiver - it does the same thing! But, the receiver acquires the transmitter signal almost instantly (no boot up for analog electronics) so the spurious servo movement is hardly noticeable.

[XPS]

The XtremeLink system boots in about 80ms. Servos often have a small delay before they are up and running too.