PART III ELECTRICAL SYSTEM OF THE UNIT
3-13
ENGLISH
Infrared light is also known as plain-old "heat." The basic premise at work in an IR remote control is the use of light to
carry signals between a remote control and the device it's directing. Infrared light is in the invisible portion of the
electromagnetic spectrum. An IR remote control (the transmitter) sends out pulses of infrared light that represent
specific binary codes. These binary codes correspond to commands, such as Power, Speed or Timer. The IR receiver
in the device decodes the pulses of light into the binary data (ones and zeroes) that the device's microprocessor can
understand. The microprocessor then carries out the corresponding command. The basic parts involved in sending an
IR signal include: Buttons, Integrated circuit, Button contacts and Light-emitting diode (LED).
Fig. 3.8-1 Remote control circuit board (3V dc).
Fig. 3.8-2 The remote control button
contacts and painted conductive coating in
the backside of the sticker.
Radio
Mircowave
Infrared
Visible
Ultraviolet
X-Ray
Gamma
Ray
3.8 REMOTE CONTROL
Generally, there are two types of remote controls: infrared (IR), and radio frequency (RF). Infrared remote controls work
by sending pulses of infrared light to a device, while RF remote controls use radio waves in much the same way.
Button contact
circuits (32)
Capacitor
Circuit board
LED
LED
Integrated Circuit
Painted coat inside the
keypads of the sticker
Button contac circuit
Remote control work process
Pushing a button on a remote control sets in motion a
series of events that causes the controlled device to
carry out a command. The process works like this:
You push the "Speed" button on your remote control,
causing it to touch the button contact beneath it and
complete the "Speed" circuit on the circuit board. The
integrated circuit detects this. The integrated circuit
sends the binary "Speed" command to the LED at the
top of the remote. The LED sends out a series of light
pulses that corresponds to the binary "Speed"
command. The remote signal includes more than the
command for "Speed" though. It carries several chunks
of information to the receiving device, including: a "start"
command, the command code for "Speed", the device
address, a "stop" command (triggered when you release
the "Speed" button).
The unit remote control
The unit applies a thin remote control. The backside of the
keypads contacts are painted and coating with conductive
materials. When the painted coating touches the button
contact circuit on the remote circuit board, the LED at the
top of the remote send out infrared light signal to the unit
remote receiver so that the microprocessor can carries out
the corresponding command (Fig. 3.8-2). If the button
cannot be released after pressing, the remote control does
not work. The reason is signal is not stopped and can not
send out other signals you desired.
SPEED
Summary of Contents for R200T
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