Creating and automatic chemistry buret with arduino

Projects General Guidance
1

Hello,
I am trying to make at home for personal and educational purposes and automatic buret (see photo) with arduino for acid/base titration.

The buret faucet is connected to a servomotor. First thing, i need to calibrate the buret.

For this, i would like to buy and try VL53L1X sensor for mesuring lever of water (so it supposed to measure the distance between the sensor and the top level water inside the buret with light Time of flight).

I fulfill the buret with water.

Then I would like to fix the sensor at the buret's top the sensor pointing to the water.

Then, i open the tap's buret thanks to servomotor and liquid starts slowly flowing.

I close the tap for a few seconds, and then open the tap again for a few seconds, close it again and so on...

I would like to see in my computer the value from the volume of water that i have push off from the buret each time the tap from the buret is switched off, so i need to know the distance between the sensor and the level of water (to find a linear correlation between distance and volume).

Does this sensor sensitive enough for this? Do you think it's going to work with a colorless liquid (water, chlorhydric acid,...)

Buret is 70 cm height and 1 cm diameter.

Thank you !

Burette
Burette1499×3188 133 KB

2

Hi,
Accuracy

VL53L1X datasheet.

see : 3.2 Accuracy, repeatability, and ranging error definitions

3

Under favorable conditions, such as low ambient light with a high-reflectivity target, the sensor can report distances up to 4 m (13 ft) with 1 mm resolution.

Ummmm ... may not be accurate enough for Op

I have not had my morning coffee, so I am not going to do the math; but 1mm of fluid height in a 1cm diameter tube can easily be converted to dropplets.

To me, I would likely suggest Op forget LiDAR and count dropplets from the end of the cpu-controlled valve through the burette tip.

4

Is the need to create an automatic burette or to dispense a precise volume of fluid? Those are not the same things.

5

Look for a reversible peristaltic pump?

6

I will program first to dispense 1 mL by 1 mL.... but when i will be close from "equivalence" of titration (arduino is connected to a pH sensor too), the program will decrease the volume of liquid dispensed with a shorter rotation from the servomotor.

7

You can generally get 1ml precision from a good peristaltic pump.
If a high quality pump is too expensive, there are projects online to build even more precise pumps using syringes.

8

Syringe pumps can be very accurate, and are easy to make using a stepper motor with lead screw. One example

9

That has a 27° field of view so it probably isn't suitable for looking down a narrow bore.

10

Hummm...., yes, you are probably right....i must find another sensor model with very narrow field.

11

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