How Can I Use RFID to Open Pet Doors?

I want to use the RFID microchips in my dogs to activate an automatic opening door. There are microchip reader doors that unlock a flap-type door, and there are automatic opening doors that are activated by a sound-generating collar. I have not seen an automatic opening pet door that senses the microchip in the pet for ID purposes to activate the opening. I am considering retrofitting the switch into a PX-1 model door. The issues to consider: Is the pet moving toward the door, vs. just passing by or sleeping near the door? What is the range? And is it adjustable? I am thinking the direction sensing can be from two sensors at different ranges. This product would sell easily, and if anyone out there could prototype a door, I'll be the tester.

—Greg

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Greg,

There are three different types of passive RFID technologies: low-frequency (125 to 134 kHz), high-frequency (13.56 MHz) and ultrahigh-frequency (860 to 960 MHz). UHF has the longest read range (30 feet or more), while UHF readers emit beams of energy and the tags reflect back a signal using something called backscatter. The length of the beam can be scaled back by reducing the power output of the reader and attenuating the reader antenna's signal, but the read field is not easily defined. Radio waves bounce off things and might open the door when the pet was 10 feet away.

LF and HF each have a read range of about 3 feet, and it's much easier to control the read range of such technologies. The reader creates a bubble of energy that can be increased or decreased in size by changing the power output and the size of the reader antenna. If an animal walked into this read field, the tag under its skin or in its collar would trigger the door to open. You would need to experiment a little to get the size of the read field right.

Mark Roberti
Founder and Editor
RFID Journal