Hi, I am devising a system to sort out 4 types of different material into 4 different bins in an automatic fashion. For this I was thinking
of using some sort of cheap tag on each item that can be read to see whether it is type 1,2,3, or 4.
what kind of tagging system can I use for this? any recommendations?
A 2 or 3 bit tag would be enough.
cost is very important
I though of chipless RFID tags but I could not find place where I can buy them. They are cheaper than ordinary
rfid tags, and have enough capacity for my work. They are radio wireless based therefore making automation easy.
I would appreciate it Do you know where can I purchase couple of chipless rfid tags? or you have any other alternative.
Curious as to what a "chipless RFID tag" might be?
As I understand it, most of the common security tags on products consist of a simple coil (often printed foil on paper) and capacitor which resonate at a particular frequency. The security gates presumably sweep across the frequency range looking for a resonance (the resonant frequency will alter markedly in the proximity of other materials to the tag). They are easily made, though as with everything else, tedious to produce in quantity without the appropriate manufacturing automation.
And you have to have - or construct - the detector unit.
So... some kind of programmable tag that you could program with 0, 1, 2, or 3. What frequency? You'll need to keep them physically separated while going through detection as there is no collision detection built into these kinds of passive tags. But it can be done.
Grumpy_Mike:
What sort of material do you want to attaché them to? The "product effect" will limit what you can use. For examples normally metals are right out.
I am trying to sort the materials into 4 categories: plastic, metal, glass and paper. I know metals tend to interfere with the RFID signals but I have read about the new generation of tags that solve these problem:
Clearly you need something akin to a signal analyzer to read such tags which won't be cheap,
even if the tags can be printed dirt cheap, I suspect this is research, not product.
That research paper does not address the problem of mounting on metal. This can be addressed by using thin ferrite sheet material between the tag and the tagged.
But as you say all very experimental.
So, you want to attach tags to pieces of recycling garbage ? That doesn't make sense. It would be easier to detect what the objects are, by other means.