The Memory Wallet – Arjun Kalyanpur

Imagine you go to a bar or restaurant, indulge and imbibe, and decide on the spot to get up and go to a new place. You’re feeling free and happy; the night’s going so well!

Riding this sense of exhilaration, you decide “why not!” and tell your friends “this cab’s on me”. You pull out your wallet, only to find that you left your credit card 40 blocks and two glasses of wine behind. Embarrassment and a sense of loss take over. Your night is ruined.

But no longer! Enter “The Memory Wallet”. This proof-of-concept show what happens when an intelligent yet elegant switch is incorporated into one’s wallet.

A built-in circuit is interrupted by your card of choice. When you remove said card and close your wallet, it completes the circuit, jump starting a red LED that flashes at you and reminds you to always, always, close your tab!

The code itself is relatively simple, utilizing a pull-up resistor and digitalRead and digitalWrite commands to signal the LED to begin flashing when the switch is connected.

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This was such a fun project, and I’d love to see what other complexity and code I could incorporate with some more time in the future!