I guess a magnetic reed switch wouldnt be sensitive enough? This device
that is often used for door and window alarms by moving a magnet towards
or away from the switch. I am guessing that 20-30mm is the normal
actuation distance. No doubt you could increase that distance by using a
stronger electromagnet

Cheers Bob VK2YQA

fh03 wrote:
So I was
wondering is there a way to create a magnetic field at the source to
generate an induced current in this tag