How The FASTag Sticker Works Without Any Battery Or Solar Cell?
FASTag is an electronic toll collection system in India, operated by the National Highway Authority of India (NHAI). It is a simple-to-use, rechargeable tag which enables automatic deduction of toll charges and lets you pass through the toll plaza without stopping for the cash transaction.
The FASTag employs radio frequency identification (RFID) technology. It is a thin sticker, slightly longer than a credit card—usually 10cm x 5cm in India. It is affixed on the vehicle’s windscreen after the FASTag account is activated. Just like RFID smart card for Metro, you can recharge it once the amount is exhausted.
Whenever the vehicle with FASTag sticker (Fig. 1) passes through the toll plaza, the RFID reader installed on top at the toll plaza automatically captures the FASTag details (like tag ID, vehicle class, etc) and sends it to the acquiring bank for processing and deducts the amount from the tag holder’s bank account.
The RFID technology consists of a tag and a reader. Again, there are passive and active tags. Passive tag does not use battery or solar cell or external power source, whereas active tag uses a battery.
Passive RFID requires a high-power RFID reader that sends out a high-power RF signal to passive tags. The electromagnetic energy transmitted from the RFID reader is received by a passive tag through its antenna. This received energy powers up the tag. That is, the energy flowing through its antenna wakes up the circuit. The tag then transmits a coded message back to the reader, which further processes the information. Passive RFID range is roughly about five metres from the RFID reader. Passive RFID tag is simple with no battery and can last virtually forever.
The current FASTag system in India uses passive tags. It does not require battery to operate but is completely dependent on the reader for the required power. Since it does not have battery, hence its charging is not required.