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I am trying to develop a data logger application with the TMS37157 smart RFID chip.
Can anyone help me find a HI POWER, LONG RANGE (1-2 meter) reader that will work with this chip? I would prefer something that is in commercial production that we could buy off the shelf after arranging a demonstration with the manufacturer.
I would also enjoy chatting with anyone who has actually created a working application using this chip to share ideas and solutions.
Kelly Borsum, P.E., 1-619-794-7788 in southern California
Hi Helfried!
First MANY thanks for the referral.
Next, I used two ferrite antennas from Coilcraft that I've been using as direct replacements for the unavailable Neosids, and placed them on the TAG board with the TMS37157. I haven't modified either of the two readers I have. I did the math and used a 2% cap that put the resonant frequency in the 130KHz range. The tag's voltage seemed to be reasonable in the 5-6V range, but there was no data coming back from the tag. I'll try it with a battery shortly and see what happens. Your friend indicated that two antennas at 90 degrees would give a 45 degree vector, and we really needed three separate antennas with their own drivers.
One of the things that came out of the looong chat with the folks in Houston, there was and perhaps still is another chip that provided for 3-D antennas (3 separate circuits for three orthogonal antennas). He remembered it as having a part number something like TMS37126 and it was used as a smart tag in measuring displacement in bridge abuttments at about 20 feet deep. I did find a TMS37F128 3D keyfob, but we definitely need some way of transfering data from a uC at the TAG end. If you know of such a chip that existed at some time in the past, could you send me information on it? I might be able to find some somewhere in the supply chain. If it is still in production, then you will probably hear the shouts of joy :-)
The -128 3D tag included a design for driving three high power antennas separately using a UCC27424 (SCBA031). This might work for the reader, but we are thinking that the TAG also needs the 3D antenna system since there is know way we would know the orientation of the tag in the animal.
Best regards for now.
Kelly