PX4FLOW spikes on data output

Yes it looks like its running fine. Just can’t test the vehicle with apm planner, and don’t have a window laptop here. The px4flow still doesn’t seems to work though.

The parameter list issue comes from using router. after switch back to hotspot it works. The opt_flow outputs contant none zero value at flow_comp_m_x and flow_comp_m_y, and the rest is zero. The ground_distance is taken from the lidar lite now. I am seeing hope :slight_smile: Currently on 3.6-dev

I see this appearing repeately
[MAV 001:1] EKF2 IMU0 is using optical flow
[MAV 001:1] EKF2 IMU0 has stopped aiding
This keeps appearing

you can kill the process, sudo systemctl stop ros.service in order to disable sudo systemctl disable ros.service.



I think it wasn’t the problem. I was able to run the arducopter 3.6-dev now, however optical flow still not functioning correctly.btw, do you know where I can find the launch file of the gcs bridge in erle? I need to setup gcs id for override purposes


If you’re using “frambuesa” OS, you can found the launch file under /opt/ros/kinetic folder. If you’re using the “escarlata”, the path is /home/erle/ros_ws.



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Hey @LanderU , thanks for coming in :slight_smile:
Gentlemen, I was getting suspicious , so I decided to give it a try.
So I installed my HomeBrew PXF MINI cape

On a RPI 2B and compiled the latest master and connected my Px4Flow & Lidar Lite V3.
did sudo ./arducopter -C udp:my.ground.station.pc:14550 and opened Mission Planner
I enabled the optical flow and the range finder as type 15.

Rebooted and voilà , optical flow signal and rangefinder signal :


Good to know px4flow can be used! I am getting super jealous. Maybe I should try it with Mission Planner instead. Did you also connected them on different I2C buses?

Yes you should Use Mission planner in this particular case.
I just have one I2C bus so both sensors are connected using the DIY Hub as shown in previous pictures.

I suspect that your Px4Flow might not flashed with the correct firmware.

I flashed it with the firmware I got from qgroudncontrol. Which version are you using?

This one

The first step:
Download and unzip the PX4Flow-KLT firmware https://github.com/priseborough/px4flow/tree/klt_flow

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I have lots of communication issue with mission planner in general. However, with the previously flashed firmware from qgroundcontrol I was able to read images from the mission planner.

I am losing faith. Maybe this is a issue with I2C bus on raps pi 3? Or something with erle firmware? As far as I know, no erle user has bought px4flow to work… Maybe not a coincidence.

Well, if you have uploaded the correct firmware on the Px4Flow and still canoot read the signal on Mission Planner , @LanderU will have to either fix it or ship me an ErleBrain :wink:

I guess so… thanks for the support anyways!

The USB port works fine for the px4flow, and I receive meaningful ROS messages. Is there a way to feed this information to ardupilot’s optical flow read? I am not afraid to compile something from source.

I really need to get my project to work :smirk:


are you using the latest master?



Hi @LanderU

I tried first with the latest master 3.6dev and it is giving one constant value.( And it didn’t work well with APM planner 2.0.25rc)
I was at 3.4rc2(the version erle is usually on) when I observe the spikes.

However I also need a higher version then this for my lidarlite v3 to work, so my next plan is to test 3.5rc7.

Hi @ppoirier,

are you using the current master?



Quite sure he did :slight_smile: Although I didn’t use Mission Planner. But both Qgroundcontrol and APM shows I am reading constant value

Yes ,I just cloned master , waf configure with erlebrain2 and waf copter

@LanderU thanks for the update
@JD-ETH I think I might have the answer why Px4Flow does not work with GCS

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