The Lillypad is a platform like device that you keep in you refrigerator. Placing your milk bottle on it allows you to receive automatic SMS notifications when you are running out of milk. It can also update a status incase you acknowledge the notification so that, others back at home can know if you have read the message. It does so by changing the color of the button's glow from red to green.
Development process and schematics of the Lillypad
The glow under the capacitive button is created by a pair of LEDs placed under the button. I used the IFTTT (If this, then that) service to send out SMS notifications and receive acknowledgements.