dimension measurement with a sensor

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raunak parekh

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can anyone let me know is there some sensor available to measure dimensions like length, height, thickness, radius of an object.?

can some sensor measure 'anyone' of above quantities?
please lemme know the name of such sensor?
 

Hi

fingers? eyes? camera? laser?

give more information:
Measuring the length of a molecule (size) is toltally different from measuring length of sheet of paper (straight) and totally different form the length of a road (with kurves).


Klaus
 

raunak parekh said:
can anyone let me know is there some sensor available to measure dimensions like length, height, thickness, radius of an object.?

can some sensor measure 'anyone' of above quantities?
please lemme know the name of such sensor?
Click to expand...

To my knowledge a calibrated TV camera can be used. To calibrate, use basic trigonometry to input pictures of an object along with known scales located near it.
For thickness measurement one can use ultrasonic sensors or microwave sensors if material parameters are known.
Radius can be measured also by the calibrated TV camera along with comparison objects with known dimensions
 
sorry i made it very general. i wish to measure thickness and radius of a washer (a small circular disc like coin). hence to detect the same i need a sensor.
please something worthwhile to use.

thanks alot for ur help and replies.
 

Hi,

usually with washers you like to know:
* inner diameter
* outer diameter
* concentircity
* thickness

the first three you can get with a band conveyor with constant speed and a line scan camera,
nowadays one tend to go to a standard two dimensional camera.

The calculations are done with DSP or PC and image processing.
The selection with compressed air.

***********

The thickness is problematic because during production of the washer it gets somehow spheric.
Maybe the better way is to test thickness before the stamping process.


Good luck

Klaus
 
what if i need to do it for a standalone system where i dont have access to computer? can a microcontroller do that for me? if i program it?

hey, can i measure thickness with a ir (infra red) or optical sensor?
 

Hi,

microcontroller?
I think it is possible, but i´d go for DSP, because it is optimized for things like image processing.
Maybe ARM processors are possible if you don´t like DSPs.
Or go for an FPGA solution, but then you need an FPGA expert.
(before you go this way discuss the application with an expert)

Another point is processing speed.
How much washers per second do you need to test?

Mind: maybe there are washers on each other. How to handle this?

Klaus
 

sir, its not about rate of measurement because mine is not a factory or production related project. you may assume something like....... aaa.... ya as in vending machine... in vending machine, people put coins one by one at a time.

further please reply can distance be measured with an ir sensor?
 

To measure distance from 0.5 to 10 meters there are low-cost commercial ultrasonic models available. Laser distance meters cost more and operate up to 50 meters.
An IR sensor can measure distance, usually short distance (0-10 cm) but a better precision. Check Keyence, for instance. If you can attach a reflector on the target, you can make a distance meter measuring time-of-flight for up to 10-20 meters. Commercial models are available, too.
 

Hi,

i hope the thickness of the washers is not in the range of some meters.


About IR thickness measurement... i don´t know.

for the millimeter range i can imagine capacitive sensors.
Or eddy current sensors?

Klaus
 

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