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Topic: Laser class 2 rangefinder in tube with liquid (Read 325 times) previous topic - next topic

mawuhe

Apr 01, 2020, 08:29 am Last Edit: Apr 03, 2020, 10:11 am by mawuhe
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)


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

Laser class: 1
Wavelength: 905 nm


Slamtec Lidar lite V3 pixhawk.
Slamtec

Laser class: 1
Wavelength: 905 nm


Then I search for rangefinders that carpenter used, and found this one:
bosch

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!




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

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 ) .


mawuhe

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 :)

mawuhe

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!

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