Measure fabric lenght workaround

Projects General Guidance
1

Hello guys,

I made a custom machine to cut fabrics and I want a way to measure the fabric length.

Here are the solutions I came up with but every of them have its own issues.
I am looking for recommendations/workaround to make any of those work.
Resolution should be 1-2mm with a range of 0.5m - 4m

  1. Use a gear with holes on the motor shaft with a hall or photo sensor.
    the problem with this is that the fabric travels 20cm for each shaft rotation which means that if I use a secondary gear with 7cm diameter each 1mm on fabric the outer of the gear will be moved around 1mm which I guess is too small to work. Correct me if I am wrong.

  2. use a laser distance sensor.
    I made a search and I found out that the sensor does not have a maximum of 4m range or the resolution is 1cm or the error is too much. I found some products with higher specs but the price is out of my budget.

Maybe I miss something? Maybe there is a sensor that I miss?

I would be very thankful for any advice.

2

Your topic was MOVED to its current forum category as it is more suitable than the original

Why did you think that your post was a suggestion for the Arduino project ?

3

You could attach an encoder to the motor shaft.

4

So an encoder of 200 counts per revolution would get you 1mm resolution.

5

Could you please recommend such a sensor? or refer a similar that might work?

6

Unfortunately, the 200-count encoders on DigiKey.com are over $100. If 2mm resolution is enough (100 counts per 20 cm) they have one for about $32:

1 Like
7

Now of course, accuracy is a whole different ball game! :astonished:

8

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