PX4Flow without Lidar possible any other suitable options?

Hey there,
thanks for this awesome community and thanks for those who Keep this runnig!

I am trying to get the PX4Flow Sensor to run on my quad but the result is not good yet. I think the problem is that I am not using a LIDAR for height measurment.
Here my Setup:
Pixhawk 2.1
ACopter 3.5.3 (now 3.5.4, did not a testfly yet)
PX4Flow without LIDAR

Unfortunatly there is no LOG-File of the last flight, let me try to explain what happend:
-I put the Quad in place and armed in loiter mode
-sometimes it started to accelerate and keep the position in 1m height.
-then it drift away a bit and i switched to stabelized and land
-back to loiter on the ground sometimes only one side accelerate so that the props touched the ground or the drone shoes some other unpleasent behavoir
–> So in conclusion it seems to me that the drone got some proplems to get a proper height measurement

After Research (PX4Flow for multiple purposes) and reading the instructions it is clear that a LIDAR get highly recommended but that is a few days ago, and so I am wondering is there any possibility to get this run without LIDAR or with cheaper additional hardware?

Thanks for taking your time!

From wiki its clearly stated that you need a lidar http://ardupilot.org/copter/docs/common-px4flow-overview.html
You need to follow each steps
Garmin lidar lite v3 is a cheaper alternative

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Hi ppoirier,
thank´s for your answer. Correctly it is written in the Manual. But sometimes I seems the Manual is not complete and up to date (that´s my Impression so far). So I just want to ask if someone got some different expierience. I did another test flight and it´s very clearly that the pixhawk can´t Keep the Level without a exact measurement.

Thank you

I can garantee that each and every steps are required :slight_smile:
The Lidar distance signal is consumed by the EKF to scale the Optical Flow as well, so no rangefinder = no opticalflow.

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You can do this: https://www.lambdrive.com/depot/Robotics/Controller/Firmware/ArduPilot/OpticalFlow.html#using-the-sonar-on-px4flow-as-rangefinder-not-recommended
But very much not recommended. Lidar is far less noisy and yields more consistent results over most surfaces.

Hi James,
thank you, that what I was looking for. But nevertheless I think I will buy a LIDAR directly and go straight for the propper way :-). I am struggling between LIDAR Lite V3 and TeraRanger One. Any advise or recommondation for these ones?! I think both will do the Job, but for the TeraRanger I do Need a I2C Adapter cable and possibly a USB Adapter cable. That means extra Money and maybe extra weight.

Thank you!

I haven’t used either of those: the earlier LidarLite had problems which I’m not sure have been resolved, and the Teraranger I don’t know much about (although I’ve used their Tower in a build, which worked better than I’d expected). I’m considering looking at the benewake TFMini. I think @ppoirier has tested them out.

Lidarlite v3 is working fine, its I2C and recommend using a decicated supply and capacitor
Benewake TFMINI has a relexion problem on short range making it useless under 40cm
Teraranger I havent tried

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Is it possible to use PX4FLOW with tfmini that uses SERIAL 4/5 port?

yes it works = You specify a Lightware serial at the specified port @ 115200baud


Please note that TFMINI has native driver now with ArduPilot