How to differentiate 2 objects having the same dimension?

Hi guys, I'm new to this forum. I apologize in advance if this topic was mentioned before. I'm currently working on a mini project. Now I want to detect 6 objects that are having the same dimension and size just that 3 of them are for A purpose, and another 3 for B purpose. What sensor can i use to differentiate them? Feasible to do so?

Thanks in advance!

Weight?

Same dimensions, even weight is the same. For example, someone puts 3 trays at a table, and he forgets to take it away. The next person comes with another 3 trays and the trays are mixed. So if the previous person came and wanted to retrieve the first 3 trays, how does he know that the bottom ones are the ones that hes looking for? We can use labeling to easily solve the problem, but is there any other ways such as using sensors to solve this kind of problem?

WAAAAAYYYYYY too vague to be able to help you.

Best I can do is say that you need to find something that is different about these objects or make something be different and find a sensor that can sense whatever that is. But without you even telling what the objects are or anything about what you want to do other than this vague description there is nothing anyone can do for you.

Color, obviously.

Are these "objects" animal, vegetable, or mineral? Is it larger than a breadbox?

Smell?

I'm sorry guys I wasn't describing my project in a way that it is understandable. The objects I meant were trays, metal trays that are used to house semiconductors. The trays are of the same height, metal smell, same color, same size, same weight.

issacchook: I'm sorry guys I wasn't describing my project in a way that it is understandable. The objects I meant were trays, metal trays that are used to house semiconductors. The trays are of the same height, metal smell, same color, same size, same weight.

OK, so what's different about them. If they aren't different then they can't be differentiated. Does that not make sense?

Put labels on them. Colored, obviously.

position in the stack? barcode labels? rfid tags? If the objects are truly identical and mixed together randomly, the problem cannot be solved.

Then what IS the difference between those trays?

You only tell is what is NOT different between them, but you DO say they ARE different.

It’s the actual difference that is important of course, as that’s where your focus of detection should be.

I see guys, my initial idea was to automate everything. Seems like in this case, the automated solution is a no go. But still I appreciate the replies, they gave me insights. THanks!

Your description is still too vague to give a reasonable response.

issacchook: Same dimensions, even weight is the same. For example, someone puts 3 trays at a table, and he forgets to take it away. The next person comes with another 3 trays and the trays are mixed. So if the previous person came and wanted to retrieve the first 3 trays, how does he know that the bottom ones are the ones that hes looking for? We can use labeling to easily solve the problem, but is there any other ways such as using sensors to solve this kind of problem?

If the 2nd person has total freedom to move the trays and rearrange them in any way they choose, then there is no way to tell the difference between identical trays, unless you want to get into some highly detailed examination of the trays, such as recording exact patterns of dents and scratches on each tray, or having the trays tested for fingerprints or residue left on the trays.

How are you currently telling the trays apart? There has to be something that differentiates them, or you wouldn't yourself be able to tell which set was which.

Labeling would work, or using trays with an embedded RFID tag or similar identification technology, but without more knowledge of how these trays are being used its hard to suggest a method.

Bar codes, if they are put into racks.

Well one way I can think of to differentiate between a number of identical objects is their location. You definitely know that they aren't all in exactly the same position. But to do anything practical with that information implies noting each object as it enters some predefined space, giving it an arbitrary identifier and tracking any and all movements of all such identified objects within the space.

But that sounds like cameras and a lot more processing power than Arduinos can provide.

Steve

david_2018: Labeling would work, or using trays with an embedded RFID tag or similar identification technology, but without more knowledge of how these trays are being used its hard to suggest a method.

He did say they were metal trays so that would rule out RFID.

issacchook: For example, someone puts 3 trays at a table, and he forgets to take it away. The next person comes with another 3 trays and the trays are mixed.

How many trays can fit on the table without stacking? How many tables are there? How do the people know which table to go to? Who/what puts parts in the trays in the beginning? Is there room on a tray for an additional item?

Seems like in this case, the automated solution is a no go.

Sounds like you’re giving up too easily.

If you make the decision to change, move, swap trays manually by walking over to the table - how do you make a decision which trays to change, move, swap?

There’s part of your mental process that hasn’t been discussed yet.

issacchook: I see guys, my initial idea was to automate everything. Seems like in this case, the automated solution is a no go. But still I appreciate the replies, they gave me insights. THanks!

If you think so. We don't know because you STILL haven't told us what the hell you are actually trying to do. If you told us the problem you are trying to solve then it may well be solvable. But as long as you keep giving us vague half-assed information without telling us anything then all we can do is throw out wild guesses and jokes.

If you really want help then come on out with it. the whole thing. Or just go away. But please stop this stupidity of asking us to help solve a problem with zero real information.