Yes, a detector, there are plenty of readers around - so something like direction finding equipment for radio transmitters or hidden bug finding
equipment. The actual data or number in these tags is not so important as the finding whether there is one in the area. With these things being so
small, we need to know -
a) if there are any in the room
b) where they are
c) if we have one in our body
d) where it has lodged
The thought I had is that it could be like a radio scanner which sweeps the frequencies for radio transmissions and then once you know what you are
dealing with, then you could use a more sensitive detector to find it in room/body/etc
Depending on where you are in the world there are different licensed radio frequencies Europe, USA, etc There are quite a few
bands used for these things
and then within the bands I think you can use
different frequencies so they dont interfere with each other.
I am sure it is more complicated than that but a proof-of-concept device might be interesting.
Edit - It seems like the Instructable is an RFID READER detector as it picks up the energy transmitted by the reader (the reader needs to do this to
allow the tags to be activated). If my understanding is correct, it only detects the reader and not the tag itself.
We would need a fairly powerful transmitter coil to energise any tags in the room and cause them to chirrup back to the device we would be using. Then
if we wanted to sweep other frequency tags we would have to change the size of the coil so that it resonated in tune with the correct frequency of the
tag we were searching for. (I dont know much about electronics as you can tell, but I think this is right. Someone correct me please if wrong)
Maybe Hitachi makes a detector for the small chips?
I suspect that they only supply readers and they probably assume you know where
you put the tags. Readers can pick up tags from a fair distance depending on the transmitted power and whether the tags are passive, semi-passive or
active ones with batteries in them. One of the links I gave in the original post mentions 300ft I think but that may be for active tags.
The read range of passive tags depends on many factors: the frequency of operation, the power of the reader, interference from metal objects or
other RF devices. In general, low-frequency tags are read from a foot or less. High frequency tags are read from about three feet and UHF tags are
read from 10 to 20 feet. Active RFID tags, on the other hand, offer very long read ranges -- up to 300 feet under optimal conditions.
for passive Hitachi RFIDs
it can operate at temperatures of -40 degrees to +85 degrees Celsius (-40 degrees to +185 degrees Fahrenheit—make it unique, he says, as does
the ability of the tag's built-in antenna to capacitively couple with a booster antenna (or other metallic object), thereby extending read range to 4
or 5 meters (13.1 feet to 16.4 feet).
edit on 15 Jun 2014 by qmantoo because: comment on instructable
edit on 15 Jun 2014 by qmantoo because: (no reason