NSF ITEST SPIRIT December Workshop 2006 WELCOME 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.

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.

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.

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): capa.org/~mmp/applist/Spectrum/s.htm capa.org/~mmp/applist/Spectrum/s.htm

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.IrDA 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.

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

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.siliconphotodiodecurrent 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.remote controls

Range Data for the TekBot IR Transmitter/Receiver 60 degree emitting angle Radiant Power (from datasheet) 35mW (MAX) Observed stable transmitting distance 10ft

References AQ.html AQ.html OCAB OCAB Assembled by: Alisa N. Gilmore, P.E. For NSF SPIRIT ITEST grant 12/2/06