An Oyster card, as described by Wikipedia, is:
a form of electronic ticketing used on public transport services primarily within the Greater London region of England. It is promoted by Transport for London and is valid on a number of different travel systems across London including London Underground, buses, the Docklands Light Railway (DLR), London Overground, trams, some river boat services and most National Rail services within the London Fare Zones.
This describes how to extract the RFID chip from an Oyster card.
- Oyster card
- Acetone (commonly found in nail polish remover)
- Submerge card in acetone until it softens.
- Peel off layer of plastic and submerge again.
- Repeat until chip is visible.
The wire for the antenna of the chip is very fine so it’s easier and quicker to extract the chip without it and opt to solder on your own antenna. The contacts on the chip are quite weak so care has to be taken not to break them off (They look like wings on either side of the chip. Should be easy to spot if you look at where the aerial connects to the chip). Encasing the chip in something like hot glue will help prevent the antenna detaching. For what it’s worth, the aerial in the card is about 13cm with 5 loops long but you may need to experiment a little to make a working replica.