Week -2

Question 1

AIM : Make a Simulink model of Doorbell using solenoid block.

Principle of Doorbell : The solenoid is an electromagnet with wire winding and a small metal plunger inside it. When electric current flows through the wire, an electromagnetic field is generated which pulls the metal plunger towards it. The metal plunger hits the bell for sound wave.

Body :

The model is created using pulse generator, scope, simulink-ps converter, switch, slover configuration, battery, electrical refrence, solenoid, mechanical translational refrence, ideal translational motion sensor, ps-simulink converter & scope.

Pulse generator is used to generate the signal input to switch. The signal needs to convert into physical signal using simulink ps converter. When the switch is on for first 2 sec. & turned off current passes through solenoid makes the plunger displaced according to the properties. The displacement caught by translational motion senser & the reading taken as plot.

Input signal of Pulse Genrator:

Input parameter for pulse generator where phase delay is 2 seconds with amplitude 1 and Pulse time is 4 secs to make it in half with 50% pulse width.

Input signal :

Output signal :

Above result is obtained for the time period of 10 sec.

Question 2

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

INPUT :

BODY : A thermistor is a resistance thermometer, or a resistor whose resistance is dependent on temperature. The term is a combination of “thermal” and “resistor”. It will sense the heater.

CONDITION 1 : 0 to 10 seconds temperature 20 °C = 293.15 K .

CONDITION 2 : 10 to 30 seconds temperature 27 °C = 300.15 K .

CONDITION 3 : 30 to 50 seconds temperature 23 °C = 296.15 K .

Fan conditions: ON if the temperature above 25 °C, OFF otherwise.

Here the temperature is converted in Kelvin from degree Celcius because the signal converter does not take °C value as input. I also have to set the signal unit as "Kelvin" in Simulink-PS Converter.

The formula for conversion: 1 °C= 273.15 K .

MODEL EXPLANATION :

1. At first, the signal is created in "Signal Builder" and further passes to "Simulink-PS Converter" to convert the input signal into the physical signal.
2. This physical signal is connected to a block "Controlled Temperature Source". This block is connected to the thermistor and a "Thermal Reference" block.
3. The thermistor is a part of an electric circuit where a battery, a voltage sensor, a resistor connected parallel to the voltage sensor, an electrical reference are connected to make a complete circuit. A solver configuration is connected to that electrical circuit to solve all parameters before the beginning of the simulation.
4. The voltage sensor senses the temperature in the form of voltage and sends the data to its port "V".
5. From this port, we get our output and send it to two different "PS-Simulink Converter".
6. From converter, the signal is sent to the threshold switch. In the switch, the threshold limit is set . If the temperature is above or equal to the threshold limit, then it gives "1" as output which is "Switch On". If the temperature is below the threshold limit, then it will give "0" as output which means "Switch Off".
7. From converter, it converts the physical signal into a Simulink signal and sends the voltage data from the Voltage Sensor to display. This display gives us the threshold value of voltage. This value is set in the switch.
8. Scope is connected with 3 ports , first port is the input signal from signal builder block . Second port is the voltage across resistor connected through PS-Simulink Converter . In last port switch is connected to the scope where we can see our output plot .

OUTPUT :