Assalamualaikum,
After doing some research and ask some lecturers, there are such sensor that have the same characteristics of what I've been searcing for my FYP. The sensor is Radio Frequency Identification (RFID). RFID is is the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking. Some tags require no battery and are powered by the electromagnetic fields used to read them. Others use a local power source and emit radio waves (electromagnetic radiation at radio frequencies). The tag contains electronically stored information which can be read from up to several metres (yards) away. Unlike a bar code, the tag does not need to be within line of sight of the reader and may be embedded in the tracked object.
the tag item is very small, it is almost the size of a grain of rice. So it will be easily to attach to the item or even at a card. This chip contain a unique radio frequency electromagnetic field so when the antenna detect the chip it will give certain signal.