Week -2

#Part 1

Title: Make a simulink model of doorbell using solenoid block.

Simulink Model:

• Description:

• Blocks used in the model:

1. Pulse Generator:

The, pulse generator block generates square wave pulses at regular intervals. The block waveform parameters, Amplitude, Pulse Width, Period, and phase delay, determines the shape of the output waveform.

2. Simulink to PS Convertor: The Simulink to PS Convertor block converts the input Simulink signal into a physical signal. Use this block to connect simulink sources or other simulink blocks to the inputs of Physical Network diagram.

3. Switch:

The switch block models a switch controlled by an external physical signal. If the external physical signal PS is greater than the value specified in the threshold parameter, then switch is closed, otherwise switch is open.

4. Solenoid:

The solenoid block represents the electrical characteristics and generated force for solenoid as shown in figure.

The block paramerters for solenoid are set as follow:

Ideal translational motion sensor:

In the above model translational motion sensor senses the motion of pluger which is placed inside core.

• The signal to the model is given through pulse generator. Pulse generator parameters are set as amplitude=1, pulse width=50%, time=4sec. So that it generates a signal as T ON=2sec, T OFF=2sec. This pulse signal is then converted into physical signal using simulink to PS convertor. The controlled voltage source provides controlled input to the solenoid circuit as pulse applied to it. During ON time of pulse Solenoid acts as magnet and attracts the plunger. At the end of TON plunger backs to original position due to spring force. this collision produces sound. Here to sense the motion of plunger translational motion sensor is used.

Output from scope:

Conclusion: Thus simulink model for doorbell using solenoid has been executed.

#Part 2:

Title: Use thermister to sense the temperature of a heater and turn on or turn off fan as per below condition. Temp. source 20 degree C from 0 to 10 sec. 27 degree celcius from 10 to 30 sec, and 23 degree celcius from 30 to 50 sec. Fan condition :ON fan if temperature above 25 degree celcius, off otherwise.

Simulink Model:

Description:

- In signal builder block desired signal is build as per condition given. The signal is generated by converting degree celcius into kelvin and corresponding values are plotted on signal builder.

- Thermister senses the temperature. This temperature is converted into voltage signal so as to operate motor and fan circuit accordingly.

- The condition that is Ton at 25 degree celcius is given to switch. Threshold is set to 0.0199V which is corresponding voltage at 25degree celcius above which the switch closes otherwise open. As soon as swich closes controlled voltage gets applied across motor terminals, results into rotation of motor.As the motor rotates fan turns on.

Output from scope:

• Temerature in kelvin:

• Voltage to corresponding Temperature:

• Speed in RPM:

• Conclusion: Thus from the above exercise we can conclude that thermistor can be used to sense themperature of a physical system and signal generated from te thermistor can be used to operate cooling system. It can also be used to turn ON the heating system when temerature falls below the operating temperature.