Sensor experience: a day of exploring sensors

  1. Alarm clock snooze button - while 'merely' a digital switch, it temporarily pauses the alarm for exactly 9 minutes.
  2. Touch-screen display - I used the touch-screen display of a self-service digital picture printing station. I believe the display is pressure-sensitive, with a thin membrane-type layer that rests atop the monitor, though it may be heat- or area-sensing (like a QProx).
  3. CD drive - the digital 'eye' of the drive passes under the surface of the CD scanning digital 1's and 0's converting that information to, say, images.
  4. Bar code scanner - I know the sensor is a bar code reader, emitting a series of red lasers recognizing the pattern of the 15 or so lined bar code, but I don't really know how it works.
  5. Credit card 'machine' - I call it a 'machine' because I don't actually know what it's called, but I'm referring to the fancy ones that you swipe your card in and then sign. There's a lot going on in there, what with the bar reader, the touch pad, and the 'pen' you sign your name with. I had one actually deny my signature when I 'signed' using a shape rather than my name. Thinking about sensors, I'd have to say this is an impressive little invention!
  6. automatic door opener - this is motion sensing, as the sensor box rests obviously above the door.
  7. Laptop - while there must be dozens of sensors in my Apple-branded laptop, I notice 2 on a daily basis. The first is what I believe to be a mechanical sensor, 'knowing' when I open my laptop, awakening it from sleep and putting it to sleep when I close it. I think the sensor is built in to the hinge that clasps it closed.
  8. Laptop - The second sensor is a light sensor, hidden somewhere to the left of the keyboard. The contrast adjusts based upon the lighting conditions of the room my laptop is in. I know it to be to the left of the keyboard because when I place my hand over the left speaker, the contrast adjusts to accommodate a low-light setting.
  9. Elevator - this 'modern miracle' uses an IR sensor (I think) to recognize presence as the door closes.