Sensors are backbone of plant automation
and robotics. Interfacing their output to the firmware is one of the
important areas in industrial applications. Understanding their
parameters is of great importance in designing a control system. Sensors
such as temperature, gas, humidity, IR, ultrasonic laser, PIR etc are
widely used in the industries. Developing projects involving such
sensors give a clear idea in understanding their use & limitations.
Data acquisition, SCADA, fuzzy logic control are few advanced level
projects those usually adopt embedded systems and requires software
domain knowledge particularly the “C” language.
Details about few sensor based projects
1. Contactless Liquid Level Controller:
A water level controlling mechanism is
developed which senses the water level in the tank without any contact
with the tank and accordingly controls the pump to fill water into the
tank. Here ultrasonic sensors are used to sense the water level in the
tank.
The ultrasonic sensor senses the liquid
level in the water tank and feeds this information to the
microcontroller. Based on the input from the sensor, the microcontroller
accordingly controls the switching of the relay switch, which is a
combination of a transistor and a MOSFET in this case. The relay is
accordingly controlled to switch on the load in case the water level is
less or switch off the load incase the water level is more.
2. Using TV remote as a cordless mouse for computer:
This system uses a TV remote as a cordless mouse to perform operations on a computer. The TV remote works on the principle of IR communication and the commands are send to the computer through a control unit.
Here the commands are sent from a TV
remote in form of modulated IR rays. These rays are received by the IR
receiver and converted to electrical signals which are given to the
microcontroller. The microcontroller converts these signals to binary
commands and sends these commands in serial form to the computer through
a level shifter IC.
3. Remote Jamming Device:
Here a device is developed which
produces IR rays which can block the rays from the TV remote. The
frequency of the IR light is same as the frequency of IR light by the TV
remote. This can be placed at the TV receiver such that the rays
received by the remote are superimposed by the IR rays emitted by this
device.
Here a timer powered by a battery is
used to produce pulses at frequency equal to the remote output signal
frequency and at more than 50% duty cycle, to drive the transistor,
which is turn provides power to the IR diode and accordingly the IR
diode emits IR rays at that frequency.
4. Speed Checker to detect rash driving on vehicles:
Rash driving is one of major reasons for
road accidents. Most of the road accidents can be prevented if the rash
driving is controlled. This is achieved by monitoring the speed of the
vehicles and accordingly generates a warning when the speed of the
vehicle increases. Here a speed checker system is designed where time
taken by the vehicle to travel from spot on the highway to another is
measured and the speed of the vehicle is accordingly calculated.
Here two IR sensors are used at two
different locations. Two timers are used which receives input from the
two sensors. Output from both the timers drive a NAND gate which in turn
drives another timer to trigger a buzzer in case of the speed going
more than the set limit. A decade counter shows the time count of the
output pulses or counts the clock pulses, i.e. the time taken to move
from IR sensor position to another. A speed limit is set and the
distance between the two spots are fixed. Incase the timing count is
less than the set time limit, the speed is known to be exceeded and
correspondingly a buzzer starts ringing to give the indication.
5. Distance measurement by ultrasonic sensor:
Ultrasonic sensor can be used to measure
distance of any object from a certain position. The sensor emits
ultrasonic waves which are reflected back by the object. The time taken
by the waves to travel back and forth is calculated and multiplied with
velocity of sound to get the distance measurement.
6. Optimum Energy Management System:
This system is used as a way to manage
the consumption of energy in an optimal way. It defines an easy way to
save energy by controlling the switching of loads in a room only on the
basis of the number of persons entering the room. The project uses IR
sensors to sense the persons entering and leaving the room and
accordingly the control unit controls the switching of the load.
7. Bidirectional Rotation of Induction Motor with Remote Control Device:
The exhaust fans used at homes are used
only to expel out hot air from the room. These fans are operated using
split phase induction motors which consist of a main winding which gets
the mains supply directly and an auxiliary winding which gets the main
supply through a capacitor. By interchanging the supply between the two
windings, the windings can be interchanged and the direction of the
motor can be changed. This project uses this principle to achieve the
bidirectional rotation of the motor. The commands for the desired
direction are given by a TV remote and accordingly the motor is rotated
in desired direction.
8. Street lights that glows on detecting vehicle movement:
The major advantage of using LEDs as
street lamps are their intensity can be controlled by controlling the
power supply to the LEDs. By sensing the arrival of vehicles, the LED
street lights can be made to be switched on only at the time when the
vehicle passes through it. This helps to save a relevant amount of
energy. This project develops a way to achieve this by using an array of
LEDs to represent the street lights and pair of IR sensors is used to
sense the number of vehicles on the way.
9. Density Based Traffic signal system using PIC microcontroller:
This system defines another way to
optimize the use of energy and also to overcome the problem of traffic
jams. By sensing the number of vehicles on each side of a junction, the
time for which red light of the traffic signal glows can be controlled
accordingly. This project achieves this by using LEDs as the traffic
lights for each side of the junction and using IR sensors for each side
to sense the number of vehicles.
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