Sensing device plz help

[bhan1992]

First of all im not sure if this is the correct topic, sorry if im wrong.
What i want to make here is a device that can emit sound when a tag is within the device range.
For example, the sound emitting device is placed on a table and a person carry a tag on him. When the person is near to that table, the device will emit sound.
I need some guide on how to achieve this. Like what component should i use?
Thanks for the reply

 

[davenn]

Google RFID systems

Dave

 

[jcaram]

RFID would work, specially if the "tag" has to be passive (no power supply), but you have to orient it correctly with respect to the reader. A quick solution with prototyping boards, would be to have an RF transmitter (cheap 430 MHz) be the "tag" transmitting some code, and the device on the table be a receiver. As soon as it can read whatever the tag is sending (known before hand), it makes a sound (piezo buzzer). If you can make the receiver/transmitter yourself, you would transmit a tone and detect power.

JP