More than 2 sensors on PX4 ArduCopter

Viktor_Zafirovski · February 9, 2019, 2:30pm

Is it possible to chain 6 rangefinders (Say, the Benewake TF Mini), straight into PX4 ports and have ArduCopter recognize them for 6 way flow control?

I’m working on a drone that will hopefully avoid crashing into things in an enclosed space and I noticed that even though I can add a rangefinder in any direction, I can only add up to 2 hard coded sensors (As read in mission planner and the official documentation).

I don’t mind reading the sensors on an Arduino Teensy and then feeding that into the single i2c port on the drone, but I need to know whether there is a native way to feed my ArduCopter with 6 sensors worth of data simultaneously for 6 way evasion.

Thank you.

james_pattison · February 9, 2019, 9:16pm

Master allows up to 10 rangefinders.

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_RangeFinder/RangeFinder.cpp

/*
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "RangeFinder.h"
#include "AP_RangeFinder_analog.h"
#include "AP_RangeFinder_PulsedLightLRF.h"
#include "AP_RangeFinder_MaxsonarI2CXL.h"
#include "AP_RangeFinder_MaxsonarSerialLV.h"

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ppoirier · February 9, 2019, 10:12pm

Viktor_Zafirovski · February 10, 2019, 11:04am

James had the technically correct answer, but Poirier, your project is literally exactly what I am looking for. I am going to try to clone your progress with 5 Benewake TF Minis for 5 way flow control (Every direction except upwards). I’ll make another forum question and ping you if I get stuck. Much MUCH appreciated.

ppoirier · February 10, 2019, 11:47am

As you probably know already, Benewake has released an I2C version of the TFMINI, and a driver should be ready soon. With these you could interface directly as @james_pattison showed.

Viktor_Zafirovski · February 10, 2019, 1:03pm

Well that would be ideal, but I’m not sure when the new driver would be arriving (or how to find out for that matter).

So if a Teensy driven chain is the best current solution, I’ll roll with that.

Viktor_Zafirovski · February 10, 2019, 1:11pm

It’s worth noting however that I’m not quite certain of your setup (I read a bunch of your other posts regarding this system). Is it:

1 x Attiny85
Multiple TF Minis
Attiny85
?

Also are you using the regular TF Mini or the Qwiic i2c version?

ppoirier · February 10, 2019, 1:25pm

It is 5 TFMINI serial talking to 5 Attiny85 that are outputting to I2C. The I2C bus is scanned by an Arduino Pro Mini that sequentially read each sensors and output as MavLink Avoidance Message on Serial to the PixRacer

Viktor_Zafirovski · February 11, 2019, 5:17pm

Excellent! Thank you very much!