Doug and I met up last Wednesday at Atomic. He shared this cool project. He’s working on different touch sensors but this experiment was to see if a coaster could detect if a beer was empty or full and give of different lighting based on that.

I guess he’s using a capacitive sensor.

This begs the question of what kind of sensors could be in a coaster.

• Capacitive: Might be able to tell something about the content of the glass. Could it just detect how often the glass was lifted? The longer it’s away from the coaster the more the person is drinking right?
• Pressure: Perhaps can figure things out.
• Temperature: We may be able to tell if the glass is empty based on cooling rate and closeness to room temperature.
• Sound: Perhaps the waves in the drink can tell us something. Or I wonder if some sort of range finder can reflect of the beer surface and tell us something.
• Optical: Maybe there’s a way of sending some light into the payload and detecting what comes back?
• Pager motor: I wonder if the absorption of the energy into the beer can be detected. When the glass is at different levels perhaps the motor would feel a different load.
• Camera: An upward facing camera?