My office frequently hosts many guests. Restrooms are shared with other businesses on the floor and require a key to access which guests are given and quite often forget to return. We are not allowed to duplicate the keys and the landlord charges a fee when they go missing. Attaching a bigger keychain like a hubcap was frowned upon by management so I came up with a Bluetooth solution using the Adafruit Feather nRF52840 Express board.
This detailed guide provides a complete solution that is much better than a wheel rim, I mean hub cap.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.