[qfqxmkuw] Emergency battery interface

A door lock with an electrical component will fail to function if it doesn't have electricity, for example, if its batt

[rysbedyh] Automatic light switch

Design a light with an ambient light sensor that automatically turns on the light when it becomes dark and turns it off

[ogihsgnx] Push to antenna

Create a NFC device whose antenna becomes connected only when the user pushes a button on it.  This seems easy and