How secure would it be to use UHF RFID wristbands to monitor the children's entrance to dangerous areas in parks and at hotels?
The answer would depend on what you mean by "secure," as I am unsure whether you are concerned that someone might clone a tag to gain access to areas of parks and hotels that they should not have access to, or whether you are concerned that tags will not be read 100 percent of the time to prevent children from being endangered. If it's the former, there are ways to use the tag identification number (TID) written into the chip by the manufacturer, as well as the serial number in the tag, to ensure that every tag is unique.
If your concern is that tags might not be read 100 percent of the time, that would depend on how the system is designed. There are wristbands with active RFID tags that broadcast a signal. These can be read virtually 100 percent of the time. Such tags are used in toll-collection systems, and they need to read the tag on every car passing a toll booth. Since active tags broadcast a signal, it is easier for a reader to pick up a signal.
Passive UHF tags have a long enough read range that a tag can be read automatically as a child approaches the dangerous area of a park or hotel. Reading the tag 100 percent of the time would mean choosing the right transponder (one sensitive enough to pick up even a weak signal from the reader and respond), and setting up the readers to ensure that power can reach the transponder and be reflected back, regardless of the tag's orientation of the child's position. You would need to perform testing in the areas where the readers would be installed in order to determine the ideal locations for reader antennas. A good systems integrator should be able to design a system that is highly reliable.
I hope this answers your question, and I look forward to seeing you at RFID Journal LIVE! in May.
—Mark Roberti, Founder and Editor, RFID Journal