Infra red camera’s and motion sensors
Electromagnetic Spectrum
Gamma rays, x-ray’s, UV, Visible Infrared and radio waves are all part of the
electromagnetic spectrum. Radiation is made up of vibrating waves of electrical
and magnetic fields. These waves travel in different wave lengthens, energies
and frequencies.

Wave lengthens- distance between each
wave, which extends from one billionth
of a meter (gamma) to a couple of meters
(radio).
 Frequency- Number of waves per second,
ranging from 1 billion waves per second (radio) to 3
billion billion waves per second (gamma).
All of these ray’s travel at the speed of light, 186,000 miles or
300,000,000 meters per second in a vacuum (e.g. space).
Infrared
Infrared is used to measure the amount of heat radiated by an object. The
vibrations of atoms and molecules in an object cause this. The higher the infrared
reading and temperature the faster the molecules and atoms our moving.
Anything above absolute zero (-273.15 degrees Celsius) produces infrared
radiation. The heat we feel on our skin is from infrared radiation and although
we can not see it the temperature-sensitive nerve endings in your skin can detect
the difference between the temperature inside your body and outside.
Infrared Cameras
Infrared Cameras are made up of detector and lens combinations, which produce
a visual picture of the infrared energy emitted by objects. The lens focuses the
waves from the radiation into an infrared sensor array. There are thousands of
sensors on the array, which convert the waves into electrical signals and then an
image. The more infrared waves emitted, the greater the amount is be picked up
by the sensors and then concentrated in to a higher temperature reading. This
lets you see how the heat is distributed.
An ice cube meltingyou can see how the
water slowly heats up.
A cup of boiling
water-see how the
heat has been
conducted through
the mug
Our Idea
Infrared cameras are incorporated in our idea as we think it would be helpful in
distinguishing a human hand from its surroundings, as it would give off a higher
amount of infrared waves. This would stop other moving objects distracting and
confusing our application. It is also very cost effective and could easily be
incorporated in a fairly modern phone. Of course we know this could not pick up
sign language alone, so we would also have to incorporate other motion
detectors.
Other Motion Detectors
Other motion detectors include:
Radar based- for example an automatic door that has a box above, which sends
out bursts of microwave radio energy and then bounces back, if there is someone
there it disrupts this pattern and the door opens.
Photo sensor – his uses a beam of light and when crossed sends of a signal to the
sensors.
We hope to use the radar based motion detector as well, so when a finger moves
it disrupts the bursts of microwave radio energy and creates an electrical picture
on the screen. This will hopefully make our application more accurate, which is
essential if it is to work.