How to make the TFMINI rangefinder talk I2C

Dave84 · February 6, 2018, 9:52pm

ok… as i have understood i must first set the sonar for arduino and after this i can wire it on it… right

rickyg32 · February 6, 2018, 10:20pm

Correct. Chances are it came the right way but be safe

chris661 · February 7, 2018, 7:05pm

@ppoirier very interesting, thanks. One question: is this a better option than the ultrasonic modules? If I ask this, this is because now we can find such modules for 8 USD on AE. Reference: GY-US42V2 Replace MB1242 / SRF02

ppoirier · February 7, 2018, 7:21pm

@chris661 Wow … this is what we call a clone

The major problem with sonar = the signal get ‘‘washed’’ when installed on a quadcopter.
And the infamous problems with EMI; I recommand everyone to read Maxbotix integration guide, it is an honest description of all the problems you might experience when dealing with sonar.

chris661 · February 7, 2018, 8:17pm

yes, the clone war…
and the VL53L0X, the problem is the short range?( 2 meters).

ppoirier · February 7, 2018, 8:28pm

Yes , they claim 2 Meter but in effectively it is 1,70M , but as you can see in this blog, I used them succesfully in an avoidance system:
https://discuss.ardupilot.org/t/avoidance-experiments-with-the-poc-and-benewake-tfmini/25277

chris661 · February 12, 2018, 10:55am

hi, to be sure to understand what you say, with one Arduino mini pro I can connect 2 sensors? or you say this is a way to use 2 couples of Arduino + sensor?

chris661 · February 19, 2018, 3:12pm

For your outside test, what was the max reliable altitude, 6 meters?

ppoirier · February 19, 2018, 3:29pm

Will resume external tests in a few weeks and report my results back

nicodh · February 20, 2018, 6:52am

i did some tests outside with the TFMINI as front obstacle avoidance rangefinder and i get some results as long as 8 meters at least. I will try to relocate the log of the flight to get the actual distance measured by the TFMINI if it is interesting.

ppoirier · February 25, 2018, 8:29pm

@nicodh ok I did some test and I confirm the “0” distance when reading over 6 Meter outdoor.
An easy work around can be implemented using the Arduino , we output 7 Meter when the distance and the signal strength is below a certain level.

I uploaded an example on my github

github.com

patrickpoirier51/TFMINI_MAXBOTIX_EMULATOR/blob/master/BeneWake_TFMINI_I2C_Maxbotic_Outdoor_Limit/BeneWake_TFMINI_I2C_Maxbotic_Outdoor_Limit.ino#L74


   if(Index<8){
     Framereceived[Index]=inChar;
     Index++;
   }
   else{
      Framereceived[Index]=inChar;
      if( Framereceived[1]=='Y'){
       if(Checksum(Framereceived, 8)==Framereceived[8]){
       distance= (uint16_t)(((Framereceived[2] + (Framereceived[3]*256))+OffSet)/Scaling);
       strength = (uint16_t)(Framereceived[4] + (Framereceived[5]*256));
       if ( (strength < strLimit) && (distance <= distLow ))  {
           distance = OutdoorMax;
             }  
        }  
        }           
      for(uint8_t i=0;i<8;i++){
      Framereceived[i]=0;
      }
     Index=0;
   }
}

The outputs reads like this ( I can be adjusted with : strLimit = 10; distLow = 46; )

nicodh · February 26, 2018, 3:06am

@ppoirier take a look at my log, i get 12meters all the time without any problem,

and this is the flight path:

i’m getting 12m without issue.
I dont know why.

nicodh · February 26, 2018, 3:10am

Just fyi, i’m using the 1.53 firmware for the TFmini.

MerkaTony · February 26, 2018, 8:57am

Dear @nicodh, is your TF Mini Connected i2C as @ppoirier has done with an arduino or is it serial direct?

nicodh · February 26, 2018, 11:51am

For now is just serial, I’m using serial 4 for this…

MerkaTony · February 26, 2018, 12:08pm

Thank you for your reply @nicodh,

Do you happen to have the FW? because i am trying to make sense with Siya from Benewake and have their latest in order to test and hopefully fix my issue.

nicodh · February 26, 2018, 12:40pm

I don’t have it with me… I will get it on Wednesday. Or I can ask someone
if you want it before that.

MerkaTony · February 26, 2018, 12:41pm

Dont like to push. as soon as you can is fine by me! Thank you

nicodh · February 28, 2018, 12:30pm

Hey Tony here is the firmware and the uploader.
1.5.3BootLoader_TFMmini(pix).zip (542.7 KB)

chris661 · March 1, 2018, 1:23pm

@ppoirier @nicodh, hi,
as you surely know there is an issue about fly away in terrain mode if RNGFND_MAX is set ower his real capacity, https://github.com/ArduPilot/ardupilot_wiki/issues/1097#event-1495573910
so my question is what would be the “secure” value for this sensor, in order not to risk for a fly away or not working RTL, 6 meters? 8 meters? Anyway, thanks for your precious investigations. Chris