ModalAI Forum

Eric Katzfey

Yes, there is ground, power, and the transmit line from the receiver. The receive line to the receiver is not connected. But this is a 4 wire UART.

Eric Katzfey

It shows that no bytes have been received over the UART. So you need to see why there are no bytes coming across. Is the receiver generating any? You can attach a oscilloscope to the transmit line from the receiver and see if it is trying to send anything. Are you sure that the receiver and transmitter are properly bound?

Eric Katzfey

Looks like the px4- version of the command isn't printing anything. You'll need to stop px4 running as a service with systemctl stop voxl-px4. Then wait a few seconds. Then start voxl-px4 from the command line in non-daemon mode with voxl-px4 -d. Once the startup script completes and you get a px4 prompt enter qshell ghst_rc status.

Moderator

I wanted to inquire about the maximum input voltage of the VOXL FPV ESC.
On one hand, the data sheet states, that it is usable for 2-6S (6-26V), under performance it is stated as 40V.

For a project we were considering a 7S battery (maximum charge voltage 29.4V).
This is above the official maximum input voltage of the VOXL FPV ESC, but below 40V.

Could you advise, if it would be possible to use the FPV ESC with a 7S battery?

Thank you very much for your support.

wilkinsaf

Hey @arvind_g3aero

So, it does look like you were able to get this working with the dev release of voxl-camera-server which is great to hear. The natural progression of a software package is through dev-> staging -> release.

So, this version of voxl-camera-server will be released in a future SDK. There will most likely not be a backport onto the 1.6.2 SDK

Eric Katzfey

Could you post a log of the drone flip?

Eric Katzfey

A drone immediately flipping over is usually caused by some combination of incorrect motor mapping, incorrect motor spin direction, and / or improper prop direction.

Alex Kushleyev

hi @nostrain ,

Thank you for providing an important detail regarding unloaded motor. I am going to test that condition with a similar motor.

I am a bit hesitant to ask you to go back to the older firmware since we have had a number of improvements since the original firmware, so we will try to figure out how to make this work.

In general, the ESC with unloaded motor should not be doing this, even while running in RPM control mode (which has been tuned for optimal response with a propeller). Ideally, the unloaded performance should not fail (while would behave differently from loaded motor).

Meanwhile, i am not sure how much value it is to do RPM step response tests with unloaded motor, because RPM controller assumes a loaded motor and the RPM controller is using the tuning parameters you provided. However, the motor behavior is extremely different without the propeller. To test realistic conditions, we typically run robustness tests like this with propeller on.

One more request, are you able to repeat the same test with the original firmware (that currently works) and set the demag_timing ESC parameter to 0. This was a feature originally put in for testing to help with low kv motors, but we later decided that this feature was not complete / robust enough to cover general use cases and it was removed. I am curious if it is helping in this case.

Alex

Eric Katzfey

Yes, you can monitor the battery data. What did you want to do with it?

Eric Katzfey

Yes, you can create custom code. Have you looked at our documentation? https://docs.modalai.com/voxl-sdk/

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