NSF ITEST SPIRIT December Workshop 2006

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NSF ITEST SPIRIT December Workshop 2006

• WELCOME
• Building an IR Controller for Your TekBot

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Building an IR Controller for Your TekBot

• Introducing IR, or Infrared, Technology
• What it is
• How it works
• How you will use it to remote control your
  TekBot.
• Ideas for Educational Experimentation with your
  TekBot IR Controller
• Design Details and Instructions for Building the
  TekBot IR controller circuitry.

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What is an IR or Infrared Transmitter?

• IR stands for Infrared. It has to do with the
  frequency the transmitter sends its data.
• IR requires line of sight with a receiver and has
  generally less range.
• RF stands for radio frequency, which is the
  frequency on which the devices transmit their
  data. RF signals can travel a great distance
  very fast, and pass through solid matter.

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What is Infrared Light?

• Infrared radiation or "light is invisible
  electromagnetic radiation that has a longer
  wavelength than visible light and is detected
  most often by its heating effect.
• The name means "below red, red being the color
  of visible light of longest wavelength.

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Background Electromagnetic Waves

• To see a cool demo of the spectrum of
  electromagnetic waves, from Radio Frequency
  through Microwave to Infrared to Visible Light,
  Ultraviolet, X-rays and Gamma rays (in order of
  increasing frequency)
• http//www.lon-capa.org/mmp/applist/Spectrum/s.ht
  m

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IR Wireless Communications

• IR data transmission is employed in short-range
  communication among computer peripherals and
  other devices that usually conform to standards
  published by IrDA, the Infrared Data Association.
  
• Remote controls and IrDA devices use infrared
  light-emitting diodes (LEDs) to emit infrared
  radiation which is focused by a plastic lens into
  a narrow beam.

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Infrared Transmitter

• Infrared light from the LED of a remote control
  as seen by a digital camera.

  
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IR Wireless Communications

• The beam is modulated, i.e. switched on and off,
  to encode the data.
• The receiver uses a silicon photodiode to convert
  the infrared radiation to an electric current. It
  responds only to the rapidly pulsing signal
  created by the transmitter, and filters out
  slowly changing infrared radiation from ambient
  light.
• Infrared communications are useful for indoor use
  in areas of high population density. IR does not
  penetrate walls and so does not interfere with
  other devices in adjoining rooms.
• Infrared is the most common way for remote
  controls to command appliances.

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Range Data for the TekBot IR Transmitter/Receiver

• 60 degree emitting angle
• Radiant Power  (from datasheet) 35mW
• (MAX) Observed stable transmitting distance 10ft

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References

• http//en.wikipedia.org/wiki/Infrared
• http//www.umass.edu/prs/SRRFTransmitterFAQ.html
• http//www.tpt.org/newtons/11/infrared.htmlVOCAB
• Assembled by Alisa N. Gilmore, P.E.
• For NSF SPIRIT ITEST grant 12/2/06