Benewake TFmini LIDAR works on Ardupilot

Hi, a question, Iā€™ve disconnected and reconnected the lidar, working ok above 30 40cm, but I have a new prearm message that I didnā€™t had before: PreArm: RTL_ALT above rangefinder max range
My MAX range is set to 600CM and RTL_ALT is 1500, seems standard, but why this message? Seems o me logic that RTL could be higher than Lidar Max range, no? Running Arducopter 3.5.5.Thanks.

RTL_ALT is 1500 is the default parameter of the pixhawk, if you know more about the pixhawk parameter, you can reset the parameter(0-8000); RNGFND_MAX_CM = 1200 is the highest range of the sensor

thanks @Joey but surprised by your answer. If you read the wiki about your product TFmini, you will see that 700cm is the max reliable recommended altitude:
RNGFND_MAX_CM = 700. This is the distance in centimeters that the rangefinder can reliably read.
So please do not tell people to change this value to 1200. And the RTL ALT to 1500 is ok to me, always used it. This was not the purpose of the questionā€¦

hi,chris661
RNGFND_MAX_CM = 1200 is the highest range of TFmini in the room, RNGFND_MAX_CM = 700 is the highest range of TFmini in outdoor

Chris,

The message, ā€œPreArm: RTL_ALT above rangefinder max rangeā€ means that it is configured to try and use the range finder during RTL I think there is a TERRAIN_FOLLOW parameter has been set to ā€œ1ā€ which means, ā€œUse in RTL and Landā€. I think itā€™s safer to leave that as 0. It will still use the lidar in althold, Loiter, PosHold when it is within range of the lidar.

Thanks @rmackay9 that was it. Will help for documentation when I will have all points clear :slight_smile:
One point, in a post you told me:
"Sorry, we donā€™t currently support blending sonar and map-based terrain following so itā€™s one or the other"
In another post Iā€™ve found this:
"In case youā€™re wondering how we decide whether to use google earth data vs lidar, if the vehicle has a lidar attached it will use it, if not, and the mission specifies terrain altitudes, google earth data will be used"
So what I understand, is that if a lidar is attached, in Auto mode (combo Terrain instead of Relative selected), the FC will use the Range Finder (between RNGFND_MIN_CM and RNGFND_MAX_CM) when TERRAIN_ENABLE is set to 1. otherwise Goggle terrain data will be use, right? In order this to work, this is mandatory to upload the Terrain Data (only possible when GPS lock is ok). right?
If Google terrain data is NOT uploaded, will Alt work only with Range Finder or nothing will work?
Thanks. Chris

We wrote some new drivers for the tfmini and tf02 recently. These will go out with Copter-3.6-rc2 in the next week or so.

If anyone wants to bench test them then a Pixhawk/Cube binary for Rover-3.4-dev and Copter-3.6-dev binary can be found here in this zip file. I definitely do not recommend flying these binaries because they havenā€™t gone through much testing.

Iā€™ve updated the wiki pages for the tfmini and tf02 to match whatā€™s in these binaries.

No pressure but all feedback is welcome!

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Cool,
I dont see the new drivers here ?
https://github.com/ArduPilot/ardupilot/tree/master/libraries/AP_RangeFinder

Hi @ppoirier,

Itā€™s still in the PR stage so it hasnā€™t made it into master yet. Looks like Francisco has found a couple of issues so Iā€™ll be resolving those now. Iā€™ll produce another .zip file as well (unless it gets pushed to master soon).

Moved to another thread: Using LIDAR for auto landing, which one?

Hi everyone. I have a question regarding the use of two lidar tfmini in a vehicle to avoid obstacles. I have a pixhawk controller 2. I changed the mode to pix mode. I connected sensors for telem1 and telem2. I configured according to the instructions. It seems that the sensors show the correct distance from the obstacle. The mission planner shows which sensor detects an obstacle. They are set up to avoid an obstacle at a distance of 1.9 m. On the table in steering mode everything seems to work correctly. Sometimes itā€™s like being stupid and turning into an obstacle instead of avoiding it. But when the vehicle moves in AUTO mode, starts to drive along the planned route and encounters the first and second obstacle, it will avoid them, but next time it starts to spin in circles. What could I do wrong, that it does not work properly?

Hi Chris,

Is the RNGFND_RMETRIC set on 1 needed? I havenā€™t found anything like this in the wikis or forums. Thanks.

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hi, I didnā€™t changed this value, thinks 1 is default.

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is it possible to use several tfminis in one drone with ardupilot? for example front, left and right directions and back as well. Is it worth of it? It is just idea to make sure drone doesnt hit the obstackles and of course to make everything safer.

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Talk to ppoirier.
He has worked out how to do it I believe.

Thank you for answer. As I read the whole thread, here was exact topic I was looking for! Avoidance Experiments with the POC and Benewake TFMINI

Wow, really nice test indeed!

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Glad it was what your looking.
Patrick P, Tridge and Randy are my heros on this site. They have all the answers. lol.

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Yes, they have lot of knowledge about this area. I like this kind of open source point of view to tune different kind of setups. This area of technology is also growing really fast and all the different kind of branches are being tested, so I have to testā€¦ or try to test :slight_smile:

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Does the sparkfun i2c version work on Copter 3.6 out of the box?

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Interesting, that BENEWAKE is now offering this Serial to I2C converter. Yes it should work OK but you need to change the I2c address.

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