Originally Posted by
castroll
Hello, first off I apologize in advance for all the stupid things I can say next (I'm pretty ignorant in this area)
as i understand... the activator loop "emit a little power

" over the air , when a transponder it's over it, it use that power to activate itself and use his own battery to send the ID , right? I'm talking about transponder with a single 2032 battery
I'm trying to figure out how i can detect myself that "power" from the loop to activate my own system (don't send anything, just use the loop as trigger)
Can someone help me in the right direction?
I don't believe that any lap timing systems for RC cars have loops that emit any energy. The transponders transmit a very short message once every few milliseconds, all the time. The loops only receive, never transmit.
There are plenty of other systems that do send a signal to the transponder. Automated toll systems operate like this.
But don't let that keep you from creating a system that operates as you desire!