Hi,


I am working on a very small project in which I have to sort objects of different materials (glass, plastic, metal, and paper) into different bins in an automatic fashion.

I was thinking of using some sort of ultra cheap DIY radio tags in order to be used for tagging each object and then read those tags using a reader and sort them into different bins.


I need a passive tagging system that is very cheap and doesn't need to store any data except that it can be categorized into 4 groups, becuase we are trying to sort 4 different types of materials. For example, we can associate each tag to one particular material type ( tag#1=glass, tag#2=plastic, tag#3=metal, and tag#4=paper) then if our object is made of the glass we stick tag#1 on it in which later can be detected by a reader and can be directed into glass bin. Any suggestions how can I implement this?


I was thinking of passive RFID tags but I am not sure if it is viable option or not, since my target cost for each tag is only few cents (I want each tag to cost less than 5 cents). Is it possible to make home-made RFID tag without any IC? I know there are chipless RFID tags but they are not commercially available for purchase right now, thus I cannot use them.

Or once somebody told me that I can make 4 different LC tank circuits that can oscillate at 4 different frequencies, therefore I can make a system in which oscillating frequency can be detected by some sort of reader. in this way I can print one type of LC tank (that correspond to certain frequency) on my object and detect which object is what? I am not sure if this is even possible since it was my first time hearing about LC circuits. Any suggestion? Any ideas?



thanks

 

I was thinking of using some sort of ultra cheap DIY radio tags in order to be used for tagging each object and then read those tags using a reader and sort them into different bins.
Thanks

Not sure I understand your challenge, but it seems to me that the difficult part is to decide what classification each object should be, not how to tag it. How will you do that?

John

 

Can we have an example of what sort of object you mean? E.g. Do they vary in size/shape and are they packaged/boxed at all? This sort of separating can be quite difficult and expensive using sensors. It's really easy for recycling companies because they have the option to grind it all down first lol . Depending on how these objects vary the option of using its mass springs to mind but this could be an issue with lighter metals.

 

Not sure I understand your challenge, but it seems to me that the difficult part is to decide what classification each object should be, not how to tag it. How will you do that?

John

Sorry for confusion. Classifying the objects is the challenge to solve here. The tagging system is supposed to be the solution. What I am trying to say is that we can tag the objects so that we can identify and classify them by reading the tags.
Objects come with the appropriate tags attached to them.

 

Can we have an example of what sort of object you mean? E.g. Do they vary in size/shape and are they packaged/boxed at all? This sort of separating can be quite difficult and expensive using sensors. It's really easy for recycling companies because they have the option to grind it all down first lol . Depending on how these objects vary the option of using its mass springs to mind but this could be an issue with lighter metals.

This is a project I am working on for a school project and I am supposed to sort small objects, such as soda can (metal), beer bottle (glass), milk carton(paper) and etc

 

Let me re-phrase my question. Assume you come up with 5 categories of items. It could be more or it could be less. The tags themselves won't be able to attach themselves to each item. So, how are you going to sort the items before or concurrent with tagging them?

John

 

Well, cost IS an issue. Tagging an empty soda can? Not realistic.

I suspect you need to classify and then bin things. Not tag them.