Introduction
Almost every modern home has one or more remote control device, such as television
or CD player. There are two major types of remote control, depending on the
transmission signal used.
This RC robot uses the first type: infrared light (IR). It is commonly used for TV and
home appliance control because of lower cost and it will not interfere with other radio
devices. However, the range is short and the remote control must point at the device.
In other words, the device must be able to “see” the control signal from the remote.
Furthermore, it does not work well outdoors because the infrared part of sunlight will
interfere the sensor.
The other type of remote control uses radio wave, it is often used in car security alarm,
radio controlled planes and video game consoles, etc. They have the advantages of
longer range, and will not be blocked by walls and objects in between. However, they
are more expensive and may interfere with other radio devices.
How does a remote control work?
Most control remotes for electronic appliances use a near infrared diode to emit a
beam of light that reaches the device. This infrared light is invisible to the human eye,
but picked up by sensors on the receiving device. Video cameras see the diode as if it
produces visible purple light. The sensor converts the light pulses into electrical signal
and passes it to the microprocessor which decodes them as commands, for example,
to turn left or move forward.
