Week -2

We have to make Simulink model of doorbell using solenoid and thermistor to sense a heater to control the fan for cooling.

Firstly we see a doorbell ring from solenoid .

The doorbell works under the principle of magnetic field where the soft iron armature get attracted to the magnetic field generated by the copper wound when electricity passed from them .

Blocks used for this simulation :

1. Pulse generator
2. Scope
3. Simulink ps
4. SPST switch
5. Battery
6. Electrical &Mechanical reference
7. Solenoid Block
8. PS Simulink.

• The pulse generated signals are generated after every 2 sec.to control the switch to the ring the bell.
• The generated signals are plotted on the scope and converted into real time environment by Simulink PS converter .
• Then according to the signal switch acts to control the flow of current to the solenoid .
• When the current is passed through is generate a magnetic field to attract the iron mature
• From the solenoid the motion is sensed using ideal motion sensor then the signals are converted into the Simulink phase to record the motion of the hammer.

Thermistor to sense the temperature of a heater to control.

This setup is completely dpend upon the thermistor in which the resistance changes with the temperature .and the sensed resistance is used to generate voltage respectively to control a circuit.

The following blocks are used for this setup.

1. Signal builder
2. Scope
3. Simulink PS
4. Thermistor
5. Battery
6. Simulink PS
7. Voltage Sensor
8. Display
9. PS Simulink
10. Threshold control switch
11. Control voltage source
12. DC motor
13. Ideal Rotational Motion Sensor
14. Electrical and mechanical reference

• The signal builder generates the time interal with various temperature as a source of heater .

Give some condition of heat source :

• T = 20 Degree Celcius For (0- 10s)
• T=27 Degree Celcius For(10-30s)
• T=23 Degree Celcius For (30- 50s)

Condition for fan

T=25 Degree celcius >on

T=25 Degree celcius<off

• Next the temperature data is passed to the thermistor to sense and generate the resistance value accordingly
• As the resistance varies according to the current ,voltage accrose it sensed using voltmeter.
• That value is input to the switch for turning on the motor
• Then at particular value dc motor starts .
• Using ideal rotational sensor the activites of dc motor is obtained for plotting the velocity and angular displacement plot.