Simulation Of Door Bell Using Solenoid And Thermistor  Controlled Fan

Simulation Of Door Bell Using Solenoid And Thermistor Controlled Fan

Aim: To make a simulink model of doorbell using solenoid and a thermistor controlled fan

Objectives:

1. Make a model of doorbell using solenoid
2. Make a simulink model which senses temperature of heater and control the ON/OFF of a Fan by the help of thermistor

Platform Used:

Matlab – simulink

Simulink model of Doorbell using solenoid

The above model of a simple doorbell works with help of a solenoid. As we all know solenoid is a device comprised of wire, the housing and a moveable plunger. When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. More simply, a solenoid converts electrical energy into mechanical energy. Followed by a switch and a battery to power up.

While pre-planning the simulink model, its decided to generate the signal using pulse generator since given condition of the switch, is closed for 2sec and released. And the movement of plunger using a ideal transition motion sensor.

Main Blocks Used

1. Pulse generator
2. Simulink P-S, S-P converter
3. Battery
4. Controlled switch
5. Solenoid
6. Ideal transition motion sensor
7. Scope

Overall Methodology

1. Desired signal is generated by the help of pulse generator
2. Sumulink converter is used to convert simulink signal to a physical signal and sent to a controlled switch which is connected across the battery
3. When the current is passed, solenoids plunger draws in.
4. The plunger motion is sensed by the ideal transitional sensor

Simulink model

Results

Generated signal

Displacement of plunger

Velocity of plunger

From the Displacement & Velocity plot, it is found that bell rang for every 2 sec .

SIMULINK MODEL OF THERMISTOR CONTROLLED FAN

In this model, a fan ON/OFF condition is controlled with respect to the temperature of a heater. The temperature of a heater is sensed with the help of a thermistor. A thermistor is a resistance thermometer or a resistor whose resistance is dependent on temperature.The term is a combination of ‘thermal’ and ‘resistor’ . It is made of metallic oxides, pressed into a bead, disk or cylindrical shape and then encapsulated with a impermeable material such as epoxy or glass.

Condition to turn ON/OFF the switch - Temperature source: 20 °C from 0 to 10 seconds, 27 °C from 10 to 30 seconds, 23 °C from 30 to 50 seconds

Fan conditions: ON if the temperature above 25 °C, OFF otherwise

Main blocks used

1. Signal builder
2. Controlled Temperature source
3. Simulink PS & SP convertor
4. Battery
5. Thermistor
6. Voltage sensor & Resistor
7. Switch
8. Controlled voltage source
9. DC motor
10. Ideal rotational motion sensor
11. Electrical and mechanical references

Methodology

1. Using signal builder the desired condition generated, that is
2. 20 Degree Celsius from 0 to 10 sec
3. 27 degree Celsius from 10 to 30 sec
4. 23 degree Celsius from 30 to 50 sec
5. Then sent through Simulink to physical converter to controlled temperature source
6. Thermistor is connected to the controlled temperature source .
7. Voltage through thermistor circuit is measured with voltage sensor and then used as the threshold value. Threshold value is determined by putting the ON condition (25 Degree Celsius ) as input to the controlled temperature source
8. Threshold value set on switch and the output is used for controlling the controlled voltage source which connected to the DC motor
9. The rotation of DC motor is sensed by Ideal rotational sensor
10. Electrical and Mechanical references are used for the proper grounding

Simulink model

Generated signal with conditions followed

Amplitude of the signal is set as temperature input with respected to time.

Results

Angular Displacement

Angular Velocity

Conclusion

From the about two plots we can conclude that Heater produced temperature of 27 degree Celsius between 0 to 10 sec , 27 degree Celsius between 10 to 30 sec and 23 degree from 30 to 50 sec.

From the Angular velocity and Angular displacement plot, we can conclude that DC motor turned ON when the condition T>25. Thus DC motor Aka Fan turned ON between 10 to 30Sec.