Week -2

Aim:

To make a simulink model of a doorbell using solenoid block.

To use a thermistor to sense the temperature of a heater & turn on or turn off the fan.

1.Door Bell

Simulink Model:

Simulink Model Explanation:

• The pulse generator is used to create square wave pulses at regular intervals.The block waveform parameters Amplitude,pulse width,period and phase delay,determine the shape of the output waveform.

• The switch block used is controlled by external physical signal.If the external signal is greater than the thresold parameter then the switch is closed, otherwise switch is open.
• The positive terminal of the switch is connected to switch and the negative terminal is connected to the electrical reference.
• The Solenoid block is connected with switch and battery and we will get a complete electrical circuit.The port c is connected with mechanical reference.
• The ideal translational sensor is connected with solenoid block R to observe the movement of the plunger.
• Scope is connected with the ideal translational sensor to get the output.
• PS-Simulink converter is used to convert the physical signal to simulink signal.
• Solver Configuration:Each physical network represented by a connected simscape blocks requires solver setting information for simulation

2.Thermistor

Given Inputs:

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

Simulink Model:

Simulink Model Explanation:

• Signal Builder block is uded to input the values as per given conditions:

At point 1,Time=0 seconds,Temperature=293 K

At point 2,Time=10 seconds,Temperature=293 K

At point 3,Time=10 seconds,Temperature=300 K

At point 4,Time=30 seconds,Temperature=300 K

At point 5,Time=30 seconds,Temperature=296 K

At point 6,Time=50 seconds,Temperature=296 K

• Controlled Temperature source represents an ideal source of thermal energy,that can maintain a controlled temperature difference regardless of the heat flow rate. The temperature difference is set by the physical signal port S. A positive temperature difference causes the temperature at port B to be greater than the temperature at port A.
• Thermistor is a type resistor whose resistanc eis based upon temperature.
• A linear resistor is used is used inorder to control the amount of current from thebattery.
• The voltage sensor is used to convert the voltage measured between two points into a physical signal.
• Voltage source which represenrs dc or ac
• electrical reference block is given
• Solver Configuration:Each physical network represented by a connected simscape blocks requires solver setting information for simulation.

Results:

Door Bell:

Time period given is 2 seconds to the Pulse generator to open and close the switch.When the switch is closed the solenoid blocks receives electrical power from the battery and the plunger move from port R to c to hit the bell and produce sound.

Thermistor:

For 0 to 10 s fan is OFF condition because temperature is 293K which is below the thresold 298K.After 10 s t6emperature goes to 300K then the switch will be in ON condition as the temperature exceeds 298K.After 30s fan will turn OFF as the temperature comes down to 296K which is below the thresold temperature of 298K.

From the above conditions, all the values are evaluated.