Week -2

Aim:-

To make a simulink model of doorbell using Solenoid and to create a situation the switch is closed for 2 seconds and then released and to observe the physical movement of the plunger.

To make the simulink model using a thermistor to sense the temperature of a heater & turn on or turn off the fan with the given conditions.

EXPLANATON:

1.DOORBELL ALARMING USING SOLENOID:

A doorbell is an alarming system used to signalling there is a visitor. In ancient times ,a simple bell used as an alarming system. In modern times updated into doorbell controlled using switch.

In this model, we use a solenoid to alarm the doorbell. A solenoid is nothing but a set of coiled wire surrounded to the piston,

If the switch is closed the current flows through the circuit it generates magnetic field in the solenoid. The magnetic field produced changes the position of the plunger resulting in the alarming of doorbell.

BLOCKS:

PULSE GENERATOR:

A pulse generator is used to generate an input signal for 2 seconds.The period denotes the total rum time of the simluation,and pulsewidth determines the on time of the signal. we assumed the pulsewidth as 20,it means 20% of 10 seconds which is mathematically 2 seconds.

BATTERY:

A battery is provides the current to generate an electromagnetic force in the coil, which then creates a magnetic field in the solenoid.

SWITCH:

A switch is used to close the circuit, if the switch is pressed . In this model , we give an input signal for 2 seconds using the pulse generator.

SOLENOID:

A solenoid is an set of coiled wire, which act as an electromagnet when current is introduced.

IDEAL TRANSLATIONAL MOTION SENSOR:

We need to observe the movement of the plunger during the switch is pressed. So we need a motion sensor to detect the motion of the plunger.

SIMULATION:

Input signal:-

PLUNGER MOVEMENT:-

RESULT:

Thus the movement of the plunger is visulaized using the scope.

2.THERMISTOR :

Aim:-

The objective the project is to use a thermistor to sense the temperature of the heater and turn on & off the fan as per the conditions given.

DEFINITION:

Thermistor

A thermistor is a semiconductor whose electrical resistance varies with respect to the temperature,it has resistance capacity more than a conducting material and less than an insulating material.

TYPES:

1.Negative temperature coefficient

2.Positive temperature coefficient

PROCEDURE:

First we have to set the input signal using the signal builder as per the given condition.

And then the input signal is given to the controlled temperature source,the positive temperature source at port B is given to the thermistor.

The voltage sensor is connected in parellel with the resistor, and the battery is connected to the positive terminal of the thermistor.

The electrical reference and the thermal reference should be given to the circuit and thermistor.

The voltage from the thermistor is given to as the input to the switch ,so only the switch will be turn on according to the threshold voltage.

SWITCH:

if the temperature rise above 25c(298k).

The switch will be turned on if the threshold is obtained,for 298k voltage is 0.01189, so the threshold is given as 0.01189.

When the output voltage is less than the threshold we gave in the switch, the fan will turn off

OUTPUT:

RESULT:

As per the given condition ,the fan will be turned on and off using the switch.