Small distance/dislocation measurement

Projects General Guidance
1

Hello everyone,

I am currently struggling with choosing the most appropriate way to measure distance/dislocation.

The project I am currently working on is a hand-held device with a slider-like moving part.
I will have to know the distance the slider is away from its starting position (0-10cm, possibly 1-11cm).
I assume only the body will have electronics inside.
The solution should not add any friction to the sliding part.

Two ideas came to my mind, but due to lack of experience with near-distance measurements it is hard for me to assess them. I would like to discuss my doubts about each of them.

  1. 1-px ToF Sensor (VL53L0X alike)
    The cone of light has pretty large angle (>20 degrees) and the moving part is fairly narrow.
    I am afraid the slider had to be several cm thick in order do get stable measurements.

  2. I came across a solution with linear encoder: [[/url]
    It seems to match the requirements, but I couldn`t find the linear encoder module and the designated stripe at online stores.

I will be grateful for any tips and hints.](How to use linear encoders with Arduino. hardware, code, and demo. - YouTube)

2

Use a standard digital caliper and measure when the movement is finished.

3

What accuracy do you require?
How will the endpoints that define the distance be identified?
How often and how quickly does this distance need to be determined?

Any details you care to add will help forum members help you.

4

Railroader:
Use a standard digital caliper and measure when the movement is finished.

I took a look how a standard digital caliper works and this approach could satisfy the requirements.
However, I would prefer to buy the parts needed instead of tearing a digital caliper apart.

jremington:
What accuracy do you require?
How will the endpoints that define the distance be identified?
How often and how quickly does this distance need to be determined?

The accuracy of +/- 1mm will be okay.
Due to mechanical reasons, the slider will be able to move across the 10cm distance, so both endpoints are defined.
Of course, there will be some, unknown at this point, offset.
Sampling rate is not crucial, let`s say 10Hz is the very minimum, every value above 30Hz would be more than enough.

There are other sensors in this project. The key point is to store their measurements with the corresponding distance the slider has been moved.
It will be perfect to store measurements of those other sensors at some specified distance points.
But as long as the measurements are taken at, say, 10-20 points during sliding, it will be sufficient.

Thanks for your help!

5

Some of the very inexpensive digital calipers can easily be modified to read the output using Arduino, described here, for example. That way you get about 0.01 mm accuracy.

6

jremington:
Some of the very inexpensive digital calipers can easily be modified to read the output using Arduino, described here, for example. That way you get about 0.01 mm accuracy.

Thanks a lot!
I'm waiting for solderable USB connectors in order to let an UNO read, manipulate and display the measurements for my lathe and also for my 3 axle mini mill.

7

Do you think, Hall sensor could also be an option here?