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Hi all,

Do anyone knows what type of sensor is available in the market to detect the size of the object. Like it area etc. How can i detect a object size.

Thanks in advance.

RE: Sensor

Hi IRstuff,

I’m trying to detect DC power supply adapter sizes. So probably 4cm by 9cm and smaller.

RE: Sensor

I'm trying to do a 'automatic cables sorter/counter'. It main purpose is to sort out different type of DC power supply adapter. The operator will pick up an adapter from a box of mixture adapter and placed it onto the conveyor belt. These adapter will go through a sensor and automatically sort out the adapter. I'm thinking to use a sensor to detect the size difference and sort it to respective boxes. Or is there a better way/sensor to sort these adapter?

RE: Sensor

That's a pretty specific situation!

The normal method for that would be weight. Use a conveyor weigher. Select some number of the type-one chargers and weigh them. Then do the same for the second style. Use the average for each with a tolerance. They'll definitely weigh different amounts. You may be able to weigh them without a conveyor and have the same hand shove them into the appropriate box after the unit beeps. It can be under a second.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Sensor

Three normalized-axis cameras could figure out volume pretty quickly... but unless you need to sort 100's/minute, seems like a human would be much better/faster at such a job.

Dan - Owner

RE: Sensor

Sounds like a machine vision system would be another route. Overhead comera as product goes by. Setup would be to add all possible images that are to be sorted into the camera. Then give some binary or integer number that you assign a sorted area to from a plc. Use an encoder on conveyor to track the product down the conveyor. Is the product conveyable and is there a way to sort the product as it goes down the conveyor? I am sure i missed something but that's the whole scope i believe.

RE: Sensor

Sounds like a job for a Cognex or similar vision system.


"It's the questions that drive us"

RE: Sensor

There are many items which are sorted by size purely mechanically, for example by rollers that are slightly angled so that the spacing slowly widens as the items progress along. Once the gap is the right size, the items fall into the bin directly below. It's normally applied to roundish items, such as tree fruits. But the essential concept might be applicable here if the adapters have a suitable width variation.

If this is related to recycling and resale, then beware that many adapters can be packaged identically but have variable electrical characteristics.

RE: Sensor

Are adapters of identical size also of identical output? Why would one sort by size?

RE: Sensor

Aside from the "why" issues, this is a classic example of a machine vision application as previously pointed out. Assuming color recognition is irrelevant, there are (relatively) low cost camera systems that can be "taught" to recognize a specific size and shape of object, with or without tolerances that can allow for slight variations. Most are now very intuitive and can be set up to give a "go/no-go" output, or communicate to a higher level system for decision making. Cognex, as also previously mentioned, is one of the bigger players in this, but now there are many others who make simpler less expensive versions for applications like yours. I used one from Balluf that I trained to recognize various different size product bottles coming down a line to a capper so that it would pick and place the correct size cap on it. Worked flawlessly, allowing the facility to have one capper for 6 different production lines all feeding into it randomly rather than 6 different cappers.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Sensor

Sorry, but if a person is handling every item to put it on conveyor, why not train the person to sort by size or any other "vision" criteria? I'll vote for machine vision, if it can do a better job to the task.


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