Remote control for home appliances is an absolute necessity in our
fast-paced life. As a result, much important has been given to this aspect and
a range of remote controls are prevalent today. One of the most common is that
which makes use of IR radiations at particular frequencies. Our product is a
Remote Operated Home Appliance or Remote controlled Home appliance. The circuit
is connected to any of the home appliances (lamp, fan, radio, etc) to make the
appliance turn on/off from a TV, VCD, VCR, Air Conditioner or DVD remote
control. The circuit can be activated from up to 10 meters. It is very easy to
build and can be assembled on a general-purpose PCB. The circuit essentially
consists of a transmitter consisting of a 555 IC; the receiver consisting of an
IR module, CD4017 IC, LED’s to indicate the reception of the IR radiations,
otherwise indicating the ON/OFF state, relay and other components.
Connect
this circuit to any of your home appliances (lamp, fan, radio, etc) to make the
appliance turn on/off from a TV, VCD or DVD remote control. The circuit can be
activated from up to 10 meters. The 38 kHz infrared (IR) rays generated by the
remote control are received by IR receiver module TSOP1738 of the circuit. Pin
1 of TSOP1738 is connected to ground, pin 2 is connected to the power supply
through resistor R5 and the output is taken from pin 3. The output signal is
amplified by transistor T1 (BC558). The amplified signal is fed to clock pin 14
of decade counter IC CD4017 (IC1). Pin 8 of IC1 is grounded, pin 16 is
connected to Vcc and pin 3 is connected to LED1 (red), which glows to indicate
that the appliance is ‘off.’
The
product consists of a remote which is the transmitter of the IR radiations and
the receiver which responds to the radiations and switches ON and OFF the
appliance.
TRANSMITTER
The transmitter is basically an astable multivibrator using 555
timer IC which provides a 38 kHz frequency at its output. The circuit here uses 555 timer IC to avoid
fast switching. (This can also achieved by using a high value capacitor across
TSOP sensor.) You can only switch the circuit after 3 seconds.
RECEIVER
Connect this circuit to any of your home
appliances (lamp, fan, radio, etc) to make the appliance turn on/off from a TV,
VCD or DVD remote control. The circuit can be activated from up to 10 meters.
Circuit Operation:
The 38 kHz infrared rays generated by the remote control are
received by IR receiver module TSOP1738 of the circuit. Pin 1 of TSOP1738 is
connected to ground, pin 2 is connected to the power supply through resistor R5
and the output is taken from pin 3. The output signal is amplified by T1 (BC558).
The amplified signal is fed to clock pin 14 of decade counter IC CD4017 (IC1).
Pin 8 of IC1 is grounded, pin 16 is connected to Vcc and pin 3 is connected to
LED1 (Red), which glows to indicate that the appliance is ‘off.’
The output of IC1 is taken from its pin 2. LED2 connected to pin 2 is used to indicate the ‘on’ state of the appliance. Transistor T2 (BC548) connected to pin 2 of IC1 drives relay RL1. Diode IN4007 (D1) acts as a freewheeling diode. The appliance to be controlled is connected between the pole of the relay and neutral terminal of mains. It gets connected to live terminal of AC mains via normally opened (N/O) contact when the relay energizes. Result, we get a relay toggling on each press on the remote.( If a DC 12 volt relay is to be operated, then a regulated DC 12 volt power supply is used and the circuit voltage should not exceed DC 5 volts). Any appliance connected to this circuit can be switched ON or OFF.
The output of IC1 is taken from its pin 2. LED2 connected to pin 2 is used to indicate the ‘on’ state of the appliance. Transistor T2 (BC548) connected to pin 2 of IC1 drives relay RL1. Diode IN4007 (D1) acts as a freewheeling diode. The appliance to be controlled is connected between the pole of the relay and neutral terminal of mains. It gets connected to live terminal of AC mains via normally opened (N/O) contact when the relay energizes. Result, we get a relay toggling on each press on the remote.( If a DC 12 volt relay is to be operated, then a regulated DC 12 volt power supply is used and the circuit voltage should not exceed DC 5 volts). Any appliance connected to this circuit can be switched ON or OFF.
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