Matthew Witheiler has a great blog post about tearing down the Coin electronic ‘credit card’. Coin is meant to replace all the credit cards in your wallet with a single electronic card that can still be used in magnetic card readers. Unfortunately Matt’s Coin card broke, but he took the opportunity to take the card apart and show what it looks like inside.
Matt found that overall Coin is a well-engineered device with very thin components that help make it so small. There are long coils at the top of the card where the magnetic strip is normally located, and these are what send data to a card reader when swiped. Interestingly the Coin card is powered by a Nordic nRF51822 system on a chip which is the same chip that’s used in Adafruit’s Bluefruit LE friends and the upcoming BBC Micro Bit. Check out Matt’s blog post for all the details.