Posts made by Eric Katzfey

@valvarez Some examples include: https://www.modalai.com/collections/expansion-board/products/m0151?variant=47083939791152 and https://www.modalai.com/products/m0141?variant=46829445513520

@valvarez No, you cannot connect two separate devices to the same UART.

@JP-Drone I understand the request. Yes, it seems like that would be a nice feature to support in voxl-mavcam-manager. We don't currently have time to develop this new feature but we will add it to our list of desired updates and hope to be able to get to it at some point. If you are able to do this update on your own please send us a merge request so that we can update the code for everyone to use.

@valvarez That is the IO board. Yes, that's part of what I was talking about. Perhaps I don't quite understand your question. I would suggest creating a wiring diagram of your proposed system and including that in this thread. We can take a look and see if looks feasible. What you are proposing is a customization to the platform that we have never attempted so the best we can do is to take a look at your proposed design and provide some feedback on it.

@Jetson-Nano Depends on what you mean by RC. If you are using a dedicated RC transmitter / receiver to control the drone then it is a separate thing. If you use a joystick with your ground control software then "RC" (or manual control) data is sent via Mavlink messages over the telemetry link.

@Jetson-Nano Here's some example code: https://gitlab.com/voxl-public/voxl-sdk/services/voxl-vision-hub/-/blob/master/src/autopilot_monitor.c?ref_type=heads#L514

@valvarez The IO board was created to allow builders of custom drones who need to use PWM ESCs and / or SBUS RC units to be able to connect to a VOXL 2 which has neither PWM nor the ability to configure UARTs for SBUS. So, for example, if you wanted to use PWM ESCs instead of our UART based ESC then you would attach the IO board to the UART that normally is connected to the ESC. Or, for RC, you would connect (as in that diagram) to the UART that normally is connected to an RC receiver. If you still want to use our ESC, the current RC and GPS then you don't have a spare UART for the IO board. One possible way to do this would be to move the GPS from it's current connector to a UART on the applications processor side and then attach the IO board to the UART that has the GPS now. This would require an add-on board that exposes such a UART.

@bkim1301 I would start by connecting the VOXL 2 UART 7 to a PC with a serial to USB cable. Make sure you can communicate back and forth using that setup and then do the same with the Teensy before connecting the Teensy and the VOXL 2 together. It's often very helpful to use an oscilloscope on the rx / tx lines to verify that there is actually data flowing.

@Jetson-Nano I think what you are trying to do is entirely possible. But it isn't anything we have ever tried. So I'm just throwing out some ideas that could maybe help you develop this. Or maybe you have some better ideas. One possibility, that I was referring to above, is to create a new program running on the Linux applications processor. It would have to use the libqrb5165-io library to get access to the UART on J19 that is mapped to the SLPI DSP. Another idea is to actually run PX4 on VOXL 2 and either use px4-listener to monitor the input_rc topic or monitor the RC_CHANNELS Mavlink message via voxl-mavlink-server or even voxl-vision-hub and use that to create an RC_CHANNELS_OVERRIDE Mavlink message to send to the external FC. I'm just brainstorming here and can't really provide much more support than offering some high level ideas.

@Jetson-Nano Instead of listening to the input_rc topic with the listener function you can now monitor the RC_CHANNELS Mavlink message from the FC v2.

@Jetson-Nano Which connector would you use for this on VOXL 2? In order to send RC values to PX4 running on an external FC v2 you need to send the RC values in an RC_CHANNELS_OVERRIDE Mavlink message. (https://mavlink.io/en/messages/common.html#RC_CHANNELS_OVERRIDE) So, you would need a custom program on the VOXL 2 to read the input from the RC receiver, create the Mavlink message, and send it to the external FC over the UART.

@Jetson-Nano It should be no different than with any other flight controller hardware running PX4. The PX4 documentation should be able to explain how to do that.

@Jetson-Nano Yes, that should work. You should be able to send heartbeats from a Python script using pymavlink and connect to the flight controller via voxl-mavlink-server. Then you should start receiving all the normal messages sent out by the flight controller to the GCS which should include the RC channels message.

@Jetson-Nano Probably should also look at the pipe for messages from the flight controller to the GCS (Labeled mavlink_to_gcs in the above diagram but you'll have to double check that name). Generally the flight controller is configured with two mavlink streams. One is the onboard stream that has high rate messages and is intended for local use (e.g. on VOXL or VOXL 2) and the other is more the default settings for communication with a GCS. You can configure what each of these streams contain in PX4. You can add streams, change stream rates, etc. all via PX4 configuration. Please refer to the PX4 documentation for details on how to do this.

@Jia-Wan Yes, you should be able to do your testing with SITL before trying it on Starling.

@Jia-Wan You can specify a secondary GCS link in the voxl-mavlink-server configuration file (/etc/modalai/voxl-mavlink-server.conf). This can be used to send your mavlink commands from your automation program.

@Kiazoa-Joao Figure 8 code is here: https://gitlab.com/voxl-public/voxl-sdk/services/voxl-vision-hub/-/blob/master/src/offboard_figure_eight.c?ref_type=heads. You can use that as a reference to make it do whatever you want.

@Mouhamed-Ndoye What is the interface to control these propulsion units? Is it standard PWM? VOXL does not have a flight controller integrated, it is only a companion computer. But VOXL 2 and VOXL 2 mini support either PX4 or ArduPilot. They, however, do not have any PWM outputs. You would need to use our VOXL 2 Digital IO expander board (https://www.modalai.com/products/voxl2-io?variant=40610514206771) in addition to the VOXL 2 to get that added capability.

@boga There's a number of ways to get it. One way, if you are using qvio, is with voxl-logger. For example: voxl-logger -v qvio will store the odometry data in /data/voxl-logger/logxxxx/run/mpa/qvio/data.csv. You can start this in a service file (e.g. /etc/systemd/system/voxl-logger.service) so that it is always generating a log

@Gary-Holmgren I'm thinking you could write a program that uses libqrb5165-io to communicate via the UART on J18 and then expose the traffic on UDP on the applications processor. Sort of like a bridge application.