Inav_I2C with US100 + Arduino nano only shows altitude up to 60cm

[minhdungDIY]

Hi guys,
I successfully set up the range finder using a US 100 sensor and an arduino nano, connected to I2C bus. I had to manually included the HCSR04 driver to the target files (as mentioned in closed issues #4 and #5). Everything seems to work fine, the altitude with US 100 is accurate. But only work up to 60cm. Above 60cm, the value just came back to -1cm.
Any idea why this is happening?
Thank you,

[DzikuVx]

On a quad? This is expected, all ultrasonic rangefinders suffer from working near propellers with all that noise and distrurbed air coming from them. Tops is like 1.5m above concrete but not always

[minhdungDIY]

Hi,
Thanks for replying,
Yes, it's on a quad. But it shouldn't get any disturbance since I was just testing on computer (INAV configurator) without props on and the motors were at stop. I tried the Arduino sketch from the link bellow and it's showing higher than 60cm:
https://github.com/trunglp/inav_sonar_i2c_arduino.
This just makes me think that there's some bug in the Arduino sketch.
This problem also was mentioned at the end of this thread:
iNavFlight/inav#2475
Let me know if you have any update on this.
Bests,

[DzikuVx]

Arduino uses this:

#ifdef USE_US100
  #define PULSE_TO_CM 59 //Multiplier pulse length to distance in [cm]
  #define MAX_RANGE 300 //Range of 4 meters
#endif

So cutoff is at 3m, not 60cm. I will try to test it in upcoming weeks

[georgekucher]

Hi guys,
@minhdungDIY thanks for mentioning.
@DzikuVx I've tried to test rangefinder on the fly but it seemed like it didn't work even on <60cm altitude. ANGLE, NAV ALTHOLD and SURFACE modes were enabled. And I was able to change altitude from the ground to 3+ meters. Is this expected behavior? Does the type of the surface matter and how much?
Here in Pawel's video everything goes smoothly.
I'll attach a log.
LOG00139(cut).TXT
And here is the video of this fly so that you see the surface.
Please help me with that.
Thanks in advance.

[georgekucher]

BTW
What is this parameter used (or not) for?

[georgekucher]

@DzikuVx
OK. I finally sorted our this sketch.
So. PULSE_TO_CM is not used for calculations of distance, at least for US 100. It is used (multiplied by MAX_RANGE) only for cutting off max range.
Another thing is that cutting off has a strange behavior. When MAX_RANGE is 300 (which is 3 meters not 4 how is written in cooment) it works only up to 60 cm. Vert weird for me. But if I set MAX_RANGE say 600 it works fine.

[georgekucher]

Tested it yesterday. Max altitude in SURFACE mode was still 60-80. No. Even not like this. Whenever I switched into SURFACE mode, whatever altitude copter was at, it went down to 60-80 cm above the ground.
Unfortunately I had a crash that very flight (bad soldering at battery). And I can't open log files. "error opening log no logs in this file could be parsed successfully" it says.
If anyone knows how to fix it I would very much appreciate for the help.
Bag coincidences(((

[englebert]

I think is the sonar sensor issue. I had bought many of these sonar modules, some works great and some just not.