How to make the TFMINI rangefinder talk I2C

ppoirier · March 21, 2018, 5:58pm

@DHank01 Good === hit the “like” button

I fly loiter using optical flow
http://ardupilot.org/copter/docs/common-px4flow-overview.html

nicodh · March 24, 2018, 6:06am

@ppoirier: Hello Patrick, i’m trying to test the TF mini poc but i’m running into a small issue. Where do you got the mavlink.h library for the teensy? I got one but the distance message is not there. So i ‘stole’ it from the cleanflight code.

Thanks!

ppoirier · March 24, 2018, 11:33am

Hello Nicolas,
I generated it using the python export script, as showed in this excellent blog: MAVLink Step by Step

DHank01 · March 27, 2018, 5:14pm

@ppoirier In testing our copter with a Pixhawk, PX4FLOW, TFMINI Lidar for altitude, with all GPS parameters turned off(Optical Flow Only), we can take off in Loiter mode and hover relatively well but after a few seconds it kicks out of LOITER mode and we get an EKF variance error and looking at the EKF gages, the horizontal position EKF is high and in the orange.
When taking off in Stabilize and trying to switch modes to POSHOLD or LOITER the flight mode change fails. Altitude seems to be fine? These issues go away when we turn the GPS back on.
Do you have any suggestions or guidance? Any log plots you would like to see?

ppoirier · March 27, 2018, 5:56pm

Hello , I answered on your topic

nicodh · March 28, 2018, 6:52am

thanks patrick…
That is what i was looking for!

After trying a while i still cant compile the project. Getting all sort of errors:

TFMINI_I2C_MAVLINK:74: error: ‘MAV_TYPE_GCS’ was not declared in this scope

‘MAV_COMP_ID_PATHPLANNER’ was not declared in this scope

Any hint?
(i followed the step by step guide)

ppoirier · March 28, 2018, 12:53pm

Seems you are missing somethink in your mavlink library
try substituingthe define by the associated numbers from this http://mavlink.org/messages/common
6 MAV_TYPE_GCS
195 MAV_COMP_ID_PATHPLANNER

nicodh · March 28, 2018, 2:32pm

The error line is longer than just the PATHPLANNER (too long to put it here without spamming).

I build the mavlink using the step by step guide in a virtualbox linux. (it was impossible run it on windows).

ppoirier · March 28, 2018, 2:36pm

I will upload my mavlink library on gitter tonight

nicodh · March 28, 2018, 2:41pm

cool thanks patrick…i don’t know why mine does not work at all.

ppoirier · March 29, 2018, 12:29am

@nicodh It is too big for github, I did a share drive

I will leave it open until you copy == let me know

nicodh · March 29, 2018, 6:57am

Thanks downloading right now

Nicolas Grunbaum

nicodh · March 29, 2018, 7:06am

Thanks Patrick, it’s done, i downloaded it, and tested it, it works.

Thanks for the help!

Nicolas Grunbaum

rickyg32 · March 31, 2018, 10:54pm

Putting this out to the community. I seem to be in need of assistance. I flashed my pro mini with no issues, its wired up and double checked. I configured the Arducopter per the instructions. But no joy.
At rest the copters altitude reports as .15 meters and if I roll the machine on its side so it measures a longer distance if measures .23 meters. If I run my hand in front of the sensor it changes numbers quickly but only in the range of .15 to .23. I am stumped.
One small change. If I give it more room to measure it gives me higher numbers, I saw it go to 40 at one point. ITs a small room so its hard to get an unobstructed range.

I did sit the machine on the bench with the lidar over the edge. Its 1 meter to the floor and it read .21. No settings for the lidar in mission planner have any effect on the numbers other then to stop it from working.
I thought this may be a symptom of it outputting in say mm over CM…but I am not sure what the results would be like its its wrong.
Any thoughts would be appreciated.

rickyg32 · April 1, 2018, 12:00am

What should it be MM or CM

ppoirier · April 1, 2018, 1:01am

Hello,
Yes it look like the TFMINI is sending in cm,
here are the commands to:
Modify output unit to mm output: 42 57 02 00 00 00 00 1A
Modify output unit to cm output: 42 57 02 00 00 00 01 1A

Uou migh try to reduce gain as well on line 32

github.com

patrickpoirier51/TFMINI_MAXBOTIX_EMULATOR/blob/master/BeneWake_TFMINI_I2C_ProMini_Maxbotic.ino#L32






#include <Wire.h>
#define I2C_SLAVE_ADDR  0x70  //Standard MaxsonarI2CXL address


uint8_t Framereceived[9]; //TFMINI received Buffer
uint8_t Index;
byte received;
uint16_t distance;      // Distance value in 16 bit word
uint8_t OffSet = 120 ;  //Offset error of the LIDAR
uint8_t Scaling = 10 ;  //Benewake outputs in mm, we have to scale to cm


//Checksum is the sum of the first 8 bytes of actual data Checksum = Byte1 + Byte2 + ... + Byte8
uint8_t Checksum(uint8_t *data, uint8_t length)
{
    uint16_t  count;
    uint16_t  Sum = 0;
    
    for (count = 0; count < length; count++)
        Sum = Sum + data[count];
    return (Sum);

rickyg32 · April 1, 2018, 12:44pm

Merci beaucoup Patrick
That was it spot on. It’s working great now.

ppoirier · April 1, 2018, 1:24pm

Bienvenue Ricky, happy it works

Hit the like button , that’s how I get paid here

rickyg32 · April 1, 2018, 1:48pm

The button…???
Point me to the button I would be glad to hit it…lol

ppoirier · April 1, 2018, 3:20pm

️. Button below just push it