We are operating
the home appliances by using an IR remote which is interfaced with the
microcontroller by using various components.
A
12v power supply is generated and it is supplied to the micro controller by
using a transformer. Atmel microcontroller based hardware is used along with
real time clock interface. The development involves writing the software code for
microcontroller at which the automation can be done. The microcontroller based
hardware is chosen to implement this concept. The loads like lights, motors,
heaters, power controlling system and also current through the loads can be
controlled in this project. We can control all loads at a time from one place
(control room) without connecting any physical wire between loads and control
room.
Since AC loads are also
controlled in this project and the microcontroller cannot handle AC loads,
TRIAC is used to control the AC loads. The speed of AC motor can be varied
rapidly on and off by TRIAC. The main advantage of using a TRIAC to vary the
speed of an AC motor is the TRIAC reduces the energy flow to the motor and
TRIAC works very well for alternating currents. Hence, in our module we use the
TSOP 1738 IR receiver, MOC 3021 TRIAC, IR remote controller, crystal oscillator
and some other related equipment. Crystal
oscillator is used to generate a frequency of 11.0592MHz. Two load capacitors
of 33 pF are used to eliminate the noise which is occurred in the oscillator. For
reset button we used one pull up switch which is connected to reset pin of
micro controller. An IR remote control device uses IR light which is invisible
light about 950nm wavelength. One biggest problem in using IR light is that
there many other sources of it like sun, light bulbs, fire. In order to exclude
other sources, IR signal is modulated by some frequency. Receiver has to be
tuned for this frequency. Mostly remote controls transmit IR signal using 36
kHz frequency signals. Here in our
module we are using TSOP1738 IR receiver which generates the frequency of 38
kHz, exactly matched with our remote controller.
Thus, we can control (i.e., switch
on/off) the home appliances by using an IR remote which is interfaced with
microcontroller.
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