Week -2

1. Make a Simulink model of Doorbell using solenoid block with the following details:

Answer:

The below-mentioned blocks are used to create a doorbell using solenoid block

• The pulse generator is used to produce a square wave for every 2-sec interval of time.
• Simulink-PS converter is used to convert the Simulink signal to a physical signal.
• The Switch is used to complete the circuit.
• The battery provides the power to the circuit.
• Electrical reference is used as a common reference for the electrical circuit.
• The movement of the plunger in the solenoid is due to the EMF.
• The ideal Translational motion sensor is used to measure the position of the plunger.
• Mechanical translational reference is used as a common reference for mechanical blocks.
• PS-Simulink converter is used to convert the physical signal to a Simulink signal which is connected to a scope.

2. Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per the below conditions:

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

Answer:

Signal builder block is used to build the signals as follows:

• For 0-10 sec, the temperature is 293.15 K
• For 10-30 sec, the temperature is 300.15 K
• For 30-50 sec, the temperature is 296.15 K

This signal is passed through the Simulink-PS converter block to the temperature source block.

Temperature is connected to the Thermistor block, which is very sensitive to the change in temperature.

Voltage sensor is used to measure the voltage across the resistor.

To turn on the fan for above 25 °C temperature, Threshold value is calculated across the resistor for the temperature of 298.15K. The threshold value is 0.01196, above which switch will turn on the fan.

Simulation result for the simulation time of 0-50 sec.