Table of Contents
Introduction:
The ‘Infra-red based device Control’ project described here is a novel approach to controlling the devices like a Fan, induction motor, incandescent bulb, or resistive heater/ Boiler with the help of a compact remote control Handset unit, from a remote place.
The main feature of this system is the total digital control of the required physical parameter, simplicity of operation, and flexibility. These features make this system very useful in the fields of Industrial Automation as well as Home Automation.
Block diagram explanation :
Power supply unit:
This section needs two voltages viz., +12 V & +5 V, as working voltages. Hence specially designed power supply is constructed to get regulated power supplies.
Buffers:
Buffers do not affect the logical state of a digital signal (i.e. a logic 1 input results in a logic 1 output whereas logic 0 input results in a logic 0 output). Buffers are normally used to provide extra current drive at the output but can also be used to regularize the logic present at an interface.
Drivers:
This section is used to drive the relay where the output is the complement of input which is applied to the drive but the current will be amplified.
Relays:
It is an electromagnetic device that is used to drive the load connected across the relay and the o/p of the relay can be connected to the controller or load for further processing.
Indicator:
This stage provides a visual indication of which relay is actuated and deactivated, by glowing respective LED or Buzzer.
IR Receiver:
The Infra-Red signal [which contains each vehicle’s registration number in RC-5 code] transmitted by the moving vehicle is received by this IR Receiver.
IR Transmitter:
The IR LED or Infra-Red Light Emitting Diode is an electronic device that gives off or emits light when current is passed through it. Like a general diode, this IR LED passes current only in one direction and requires a forward operation voltage of about 2V and forward operation current in the 10 to 20 mA range. The maximum reverse voltage that the IR LED can withstand is typically 3 to 5V, more than this could damage the component. It does not have any current control function, so, when the IR LED is used in a circuit, a resistor must be used in series to limit the current flow through it. If a greater range is required, this resistor may be reduced to a minimum value with a consequent adverse effect on current consumption
Methodology:
The remote handset consists of a switch, pulse generator, and an IR source, usually IR Led. Whenever the switch is pressed, the pulse generator generates a pulse and the IR source is powered for a time interval equal to the pulse width. The IR source and the IR sensor have to be in a straight line so that the sensor picks up the signal generated by the remote handset unit.
As soon as the IR sensor detects the pulse transmitted by the IR source, its output goes high. The output of the sensor triggers the PIC decoder. The output of the decoder triggers the relay driver stage, which in turn drives the appropriate relay, and depending on which relay is energized devices will turn ON or OFF.
Advantages:
- They are portable and lightweight.
- These devices provide comfort and convenience and can be especially helpful for people with disabilities, bedridden convalescents, and people with various mobility impairments.
- These devices can allow presenters to move about a room while speaking and so engage with the audience e.g. PowerPoint presentations.
Disadvantages:
There is a distance limit for controlling devices.
Applications:
a. Industry.
b. Garage and Gate.
c. Military.
d. Space.
