# Counting dimensions with Sensors

Hi people, i am a begginer on arduino projects but i must say this is really awesome!

I have this problem,

i want to count the dimensions X & Y of a carpet ( yes a regular carpet ). I am guessing something with light sensors, counting the time that carpet is passing of them and then use the carpet speed to determinate the dimension.

What do you suggest ? ( Is there any sensor or even entirely new aspect to do this ? )

Thank you

So we need a little more detail. Are you planning on running a wheel across the length and width of the carpet, and wanting to measure it? If that’s the case, I’d choose a rotary encoder with a lot of steps. I’d roll the wheel one full revolution and measure that distance and divide it by the number of steps of the rotary encoder. That gives you ability to then calculate the distance the wheel has rolled. For example, if you used a 64 step rotary encoder and your wheel travels 1 foot for a complete revolution, then that’s 12 / 64 = 0.1875 in per step. So if you then pushed the wheel one direction for 783 steps, that would be 783 * 0.1875 or 146.8125 inches. You get the idea.

Yeap i got it, EXCELLENT IDEA!

I'll give it a try in about 1 month i will post the results. I must say i was thinking about a solution like this, but i have a problem, my wheel will be spining if there or there isnt a carpet to pull! You see, its activated from a button on my foot.

I can't based on my human reactions to stop the right time the wheel. I need to, maybe, how long does the carpet to pass, (with static speed) and from then.. it's easy stuff :)

I appreciate your solution, i ll give it a try, but i need an alternative for the problem above.

xristos3490: I can't based on my human reactions to stop the right time the wheel. I need to, maybe, how long does the carpet to pass, (with static speed) and from then.. it's easy stuff :)

I appreciate your solution, i ll give it a try, but i need an alternative for the problem above.

I don't understand the problem. Can you please explain in greater detail? I have no idea what you are talking about.

make an array of light sensors (strip) and the carpet will cover X of them for Y seconds.

Y seconds times transport speed = width
X times sensor distance = height

First! The problem explain: A carpet will be placed on top of the machine, and it will slide along using pipes moving with a motor. (think the machine like a box with pipes on top) the machine has a button down to activate the slide! So the actual slide is controlled by me pressing the button. So the problem, is that when the carpet "ends", i will be there to release the button. I may be late and count an extra inch ...

The solution with the array of light sensors, its really suitable to my problem. Where can i find these sensors? Does the andruino shop has any?

P.s. My english isn't very good, i really try to get you understand my problem, sorry if sometimes, what i write, doesn't make any sense :)

Your English is quite good, more than good enough to be understood!

What are typical sizes (ranges) of the carpets in both directions?

think you need to design your own strip as I do not know any.

a strip can be simplified to only detect the edges.

``````---SSSSSS----------------------------SSSSSS-----  S = sensor
<------------------------------------>        max carpet size
<----------------------------->           min carpet size
``````

—SSSSSS----------------------------SSSSSS----- S = sensor
<------------------------------------> max carpet size
<-----------------------------> min carpet size

Very accurate represantation for minimize the cost. I certainly go with this solution.

Although i thought another similar solution:

Use 1 sensor that can travel along the machine with a motor with a certain speed, and count the “LOW time” to determinate the X width. Then bring it to the center, and start the timer for Y axis.

But can anyone point me to a link for buying these sort of sensors? That would much appreciated.

might be as simple as - https://www.sparkfun.com/products/9088 - ? use with a voltage divider

one with a linear motor for Y size one static for X size ..

I decide to go with the rotary solution for my first protorype. I tried to make a represantion so people who wonder for the same or similar problem, could get some ideas. I will post the results in summer cause i dont have time to test this now.

Can anyone point to a good Rotary encoder with many steps, that can provide me accurate widths?

Thank you

you can use any rotary encoder if you use gears...