Week -2

1) Door Bell model:

Simulink Model:

Input Signal : From signal builder block

Parameter Changes made:

Battery Voltage - 24V

Motion Direction of the plunger: R moves towards C when signal is given

Initial Position (Motion sensor): 5mm

Output:

Observation:

when an input signal or switch ON position signal (1) is given, the arm moves from away position to close position to ring the bell.

2) Thermistor Model:

Thermistor Model Part:

Fan model part:

Input Temperature signal:

• Input signal is given to controlled temperature source block which gives signal to the thermistor block
• Thermistor is connected to a resistance where a voltage sensor is connected parallel across the resistor to obtain the voltage signal.
• Threshold voltage value for temperature above 25deg. C is obtained
• Switch block is provided to give 1 (ON) signal when voltage value goes beyond threshold value. For rest of the time, it gives 0 (OFF) signal.
• This ON/OFF signal acts as the input signal of the voltage source block and gives corresponding voltage signal to theDC motor block.
• Rotational sensor is used to sense the motion of the DC motor.

SIMULATION:

Initially, for the changing temperature, voltage variation plot is obtained.

Now using switch block to create On/Off signal when voltage goes beyond the threshold value, output from switch block is as follows

When the temperature is above 25 deg C from 10 to 30 seconds, ON signal is produced.

This signal is fed to the DC motor part which makes the fan to be ON from 10 to 30seconds.

It is observed that the fan is turned on from 10 to 30 seconds where the temperature goes beyond 25deg C and reaches speed of 1450rad/s for the 20 seconds of time.

Note: to find the threshold voltage, a constant temperature input of 25deg.C was given to the model.