Week -2

1) Doorbell simulation using solenoid block:

Description:

Making of Simulink model of solenoid doorbell using solenoid block from simscape library.
The circuit has battery, controlled switch & solenoid block. Switch is controlled using pulse generator block and it is to be switched on for 2 secs.
Solenoid movement is captured using translational motion sensor block and a scope block.

Step-wise explaination:

1. An electric PS circuit is created containing a battery, PS switch, solenoid block & electrical reference.
2. Pulse generator block is added with parameters: amplitude=1; period=4; pulse width=50; phase delay=0. It is connected to PS switch.
3. Ideal translational motion sensor block is connected to R port of solenoid block. C port is attached to mechanical reference.
4. The input from pluse generator & output of translational motion sensor block is given to scope.

Output:

• When switch is turned on, plunger moves away from port C of solenoid block, and doesn't show oscillations because of contact damping.
• When switch is turned off, plunger moves to its previous position showing oscillations as seen in graph below.
  

2) Fan controlled by thermistor:

Description:

Using a thermistor to sense the temperature of a heater & turn on or turn off the fan as per given conditions.
A controlled temperature input is provided to thermistor A resistor is attached to it in series combination.
Voltage across the resistor is monitored and is used to turn on/off PS switch. The PS switch controls another electric circuit containing DC motor. The output of DC motor is measured using rotational motion sensor.

Step-wise explaination:

1. Signal builder block is used to generate temperature values as given in the question.
   This signal is then fed to controlled temperature source block, whose B port is connected ti thermistor & A port is connected to thermal reference block.
2. An electric circuit containing thermistor, battery and a resistor is made. Electrical reference and solver configuration is attached to it.
3. Volatge accross the resistor is measured using voltage sensor block by connecting it in parallel configuration.
4. The signal from voltage sensor is fed to PS switch which closes when the voltage is above 20 and opens otherwise.
   This switch is conntected in a electric circuit containing a battery and a DC motor.
5. Output of DC motor is measured using ideal rotational motion sensor block, whose R port is connected to R port of DC motor & C port is connected to rotational reference.
6. The input temperature from signal builder, voltage across resistor and DC motor rotational speed are given to scope block.

Output:

• Result shows that fan switches on when temp is above 25 degC and turns off when Temp becomes less than 25 degC