Laser class 2 rangefinder in tube with liquid

Other Hardware Sensors
1

hello, I am trying to find a sensor which can detect various distances in a tube with an inner diameter of 55 mm. The surface, that the sensor is pointing at is a liquid. (See picture below)

Forsøgs opsætning.png
Forsøgs opsætning.png1611×800 4.68 KB

I have the following challenge:
I have tried the VL53L1X but have troubles with the FOV (Field of view) interfering with the inner walls and makes the output between 20 mm and 60 mm. This problem is similar to what j_fdez + arduino-forum posted around a year ago.

So, I have searched various placed for a sensor with a narrow FOV and found the following two.
Lidar-lite v3HP:
Lidar
lidar lite v3HP.png
Laser class: 1
Wavelength: 905 nm

Slamtec Lidar lite V3 pixhawk.
Slamtec
Slamtec lidar lite V3 pixhawk.png
Laser class: 1
Wavelength: 905 nm

Then I search for rangefinders that carpenter used, and found this one:
bosch
Zamo.png
Laser class: 2
Wavelength: 635 nm

In the datasheet it says that at 10 m the lasers area is 9 mm, which fits perfect for my project. However, I cannot find any specification to the laser that the rangefinder is using. I looked in the datasheet, but it seems as there is no technical detail on what laser it is using.
I have considered 2 options, but any suggestion for another path is deeply valued.

  1. Buy one of the two sensor that I have found.
  2. Buy the sensor from the carpenter store and open it up and try to reverse engineer it.
    The thing that got me wondering is the difference in price. The two sensor I found varies in price between 150 to 180 dollars, compared to the carpenter rangefinder at around 30 dollars.
    Has anyone made a similar project and have the time to point me in the right direction?
    Thanks in advance!

Forsøgs opsætning.png
Forsøgs opsætning.png1611×800 4.68 KB

lidar lite v3HP.png

Slamtec lidar lite V3 pixhawk.png

Zamo.png

2

Have you considered the HC-Sr04 ultrasonic sensor? If not, I'll post a link below.

3

You could use a float with a magnet and sensor in the outside of the tube , or a float connected to a pulley and encoder - pulley rotates as float moves ( there are commercial sensors using this method ) .

4

jmann3400:
Have you considered the HC-Sr04 ultrasonic sensor? If not, I'll post a link below.

https://cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf

Tried it already, but because it is sound waves it will not work in a tube cause the soundwaves will be bounced all over the place.
But thanks anyway :slight_smile:

5

hammy:
You could use a float with a magnet and sensor in the outside of the tube , or a float connected to a pulley and encoder - pulley rotates as float moves ( there are commercial sensors using this method ) .

Thank you so much! I will look into that!