Working: 

The heart of the Lillypad is a Spark core which serves as the brain and also connects to wi-fi. A pressure sensor keeps track of the weight of any object placed on the platform indirectly through pressure and, a custom made capacitive sensor is used to make the glowing touch button. The sensor is just a piece of aluminium foil wrapped around a circular piece of card and hidden behind the button's surface.The capacitive touch sensor works simply by creating a rising edge on a 'send pin' and observing how long the capacitance of the sensor takes to charge through a high resistance. This response is read from a 'receive pin' and the difference in time between send and receive response is indicative of the capacitance. Since capacitance can be created across an insulator, the sensor is able to penetrate the touch surface and respond to the capacitance of the human body.

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.