The main aim of this project is to control the speed and
direction of DC motor using IR remote. For controlling the speed we are using
PWM technique. A pulse width modulator (PWM) is a device that may be used
as an efficient DC motor speed controller or light dimmer. This project is a
versatile device that can control DC devices which draw up to a few amps of
current.
A
PWM circuit works by making a square wave with a variable on-to-off ratio, the
average on time may be varied from 0 to 100 percent. In this manner, a variable
amount of power is transferred to the load. The main advantage of a PWM circuit
over a resistive power controller is the efficiency, at a 50% level, the PWM
will use about 50% of full power, almost all of which is transferred to the
load, a resistive controller at 50% load power would consume about 71% of full
power, 50% of the power goes to the load and the other 21% is wasted heating
the series resistor.
One additional
advantage of pulse width modulation is that the pulses reach the full supply
voltage and will produce more torque in a motor by being able to overcome the
internal motor resistances more easily.
Rotating the
motor anticlockwise or clockwise, or increasing or decreasing the speed of the
motor can be done easily with an IR remote without actually going near the
motor switches and operating them manually. The manual operation of the motor
is completely avoided in this project.
IR
remote acts as the transmitter in this project. When a button is pressed in the
remote, the signal will be passed and received by the IR receiver that is TSOP 1738
Receiver. The frequency of IR used in this project is 38 KHz. This signal is
sent to the microcontroller which decodes the signal and performs the
corresponding action in accordance with the button pressed in the remote.
The direction
and speed level will be indicated through LEDs.
This project uses regulated 5V,
500mA & 12V, 500mA power supply. 7805 three terminal voltage regulator is
used for voltage regulation. Bridge type full wave rectifier is used to rectify
the ac out put of secondary of 230/12V step down transformer.