Shopping Card Chip (size of a 1 Euro coin)

thingiverse

This shopping cart chip is for getting a shopping cart, that requires a one Euro coin to be released. Depending on the mechanism of the cart, it is possible to remove the chip right away after the cart is released, so you can't forget it when you return the cart. I have created different sizes, as the indentation in the middle is critical. If it is too big, the release mechanism of the cart will not be triggered, the chip simply does not work. If it is too small, the chip works well to release the cart, but will be locked inside the cart and you risk to forget your nicely printed chip when you return the cart. At exactly the right size, you can put your chip back in your pocket right away. I have successfully tested the chip with the 18mm indentation.