A Low Frequency RFID reader for less
than $200
Using a few different bits and pieces
from various suppliers, TIG International assembled this RFID reader
for Low Frequency RFID tags. It
was intended that this reader would connect to mobile Personal Digital
Assistant (PDA) styled devices, so it would have to be light weight,
battery powered and small enough to fit easily into a
person’s hand.
It came as a surprise to us that you
can find all the necessary bits and pieces to build a low frequency
RFID reader for less than $200. Inside
the case is a RFID reader module we sourced from electronics suppliers
with a LED and Buzzer to indicate a successful read, and we installed a
rechargeable 9V battery for a power supply and a few other components
to allow the battery to be recharged inside the unit.
On the back we put a power switch
and a DC power connector for charging input.
We attached a 9 pin DIN serial
plug to the unit wired in cross over mode so we could connect the unit
to one of our PDA devices.
 The
reader is pictured here with a Symbol SPT1800 PalmOS PDA styled device
that has an integrated bar code reader.
Using the standard communications
cable that came with the device, we now have a crude portable system
that supports bar codes and RFID in a single mobile solution. Just the thing we need for
making practical use of RFID technology in the field.
It allows us to scan bar codes and
RFID into our software solutions in any combination.
Hence we can identify components
with a bar code, a RFID tag, or both.
TIG International has also sourced
commercially produced RFID readers that couple nicely with PDA devices
like the one pictured into a “one handed” unit, and
they are reasonably priced. So
I suppose this little project was just a quick, cost effective test of
one type of RFID technology. It
enabled us to test the physical and computing aspects of using low
frequency tags and was also used in testing our some of our RFID
enabled PDA software.
The performance of this hand built
device without an external antenna was very good.
The device is pictured here
reading a tag. As
you can see the read range is limited for these Low Frequency tags and
a very simple reader. It
works about the same a most door lock RFID devices with a range of up
to about 100mm. The
data was transferred to the PDA device at 9600 baud, which resulted in
a very quick sub-second response from the read and if the tags were
suitably positioned, we were able to get more than two RFID reads per
second.
Now we were armed with a PDA device
with integrated bar code scanner and tethered RFID reader that was
looking like we were the “fastest bar code RFID mobile data
collector in the west…”
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