Distance sensor required with 0.1mm accuracy and upto 4m range

[matrixofdynamism]

For an application, I need a distance measuring sensor that has 0.1mm accuracy and no worse and can measure upto 4m easily. It will need to be incorporated into a design with a microcontroller so I can make use of the data. I have not been able to find something that matches these requirements.

The table saw contains a fence and is used in woodworking. All table saws have it. I need a sensor that help me measure the distance between the sensor and the table saw fence. This is the application.

Does anyone know what type of sensor I could use? Maybe you have done a project of such nature already.

[Conrad Hoffman]

Ultrasonic sensors have an accuracy of about 1%, so not good enough. There are LIDAR sensors used on 3D printers that do the resolution, but not the distance. I think you need an interferometric laser sensor, and that's not going to be cheap. Or, maybe a mechanical sensor based on a fine cable and rotary encoder. There was also the Trav-A-Dial used on lathes that essentially tracked a surface with a wheel- http://www.lathes.co.uk/trav-a-dial/#:~:text=An%20ingenious%20device%20%2D%20and%20widely,surfaces%20sliding%20against%20each%20other. What's your budget?

[Retirednerd2020]

A magnetic scale and pick-up for a DRO would do it for you if it works for you mechanically.  They can be made any practical length.
Have a look at dropros.com to get an idea.

[langwadt]

https://www.sra-measurement.com/high-accuracy-magnetic-linear-tape

[matrixofdynamism]

You understood the predicament that I am in. If the device is expensive, what does that really mean? 1,000£?

May there are prexisting solutions for this problem that are digital, that I can use.

[Someone]

You understood the predicament that I am in. If the device is expensive, what does that really mean? 1,000£?

May there are prexisting solutions for this problem that are digital, that I can use.

You go and talk to the suppliers:
https://www.astech.de/astech/download/ldm51-lumos/Datasheet_LDM51_EN_V1.7.pdf

Or do some research about how/why other machine tools all seem to use pre-packaged solutions:
https://www.touchdro.com/resources/getting-started/dro-scale-selection-guide.html

[David Hess]

Get a scale for a DRO.  They come in magnetic and optical versions.  The advantage of the magnetic versions is that you can cut the scale to length.