Week -2
AIM- This challenge aims to make a simulink model of a doobell using a solenoid block and make another simulink model where a thermistor will be used to sense the temperature of aheater and turn it on or turn it off the fan.
Objective:
1. Make a Simulink model of Doorbell using solenoid block with the following details:
In the above arrangement, when the switch is closed the electromagnet receives electrical power from the battery and pulls the metal arm to hit the bell producing sound. Create a situation where the switch is closed for 2 seconds and then released. Observe the physical movement of the plunger.
Solution:-
Doorbell:-
A doorbell is a signaling device typically placed near a door to a building's entrance .when a visitor presses a button the bell rings inside the building ,alerting the occupant to the presence of the visitor.the heart of a doorbell is an electromagnet.Electromagnets are coils of wire wrapped around a small piece of magnetic metal.
The magnetic field generated by the electromagnet is then used to power a mechanism that creates the doorbell sound.
Doorbells are low-voltage devices .This means they require relatively little energy to operate.An important part of a doorbell mechanism is the transformer .the transformer converts regular 120-volt household current to the lower voltage (usually somewherebetween 6-16 volts)required by the doorbell.
Solenoid:-
A solenoid is a 3- dimensional structure of wire.when the wire is wrapped around a metallic block in a coil and electricity is passed throughit,it has some special magnetic properties.
The side in which the current appears to be passing clockwise is the south pole,and the side in which the current seems to be passing anticlockwise is the northern pole.The solenoid works just like a bar magnet and therefore has many uses.
1. Pulse Generator:- The pulse generator block generates square wave pulses at regular intervals.the block waveform parameters,amplitude,pulse width,period and phase delay,determine the shape of the output waveform.
2. Simulink:- Converts the unitless simulink input signal to a physical signal.
3.Scope:- Display signals generated during simulation.
4. Switch:- Switch contrilled by an external physical signal.
5.Battery:- The battery block represents a simple battery model.
6.Solenoid:- Model electrical characteristics and generated force of solenoid.
7.Ideal Translational Motion Sensor:- The ideal translational motion sensor block represents a device that converts an across variable measured between two mechanical translational nodes into a control signal proportional to velocity or position.
Thes sensor is ideal since it does not account for inertia,friction,delays,energy consumption,and so on.
8.Mechanical Translational Reference:- The mechanical Reference block represents an electrical ground.electrical conversing ports for all mechanical translational ports. all translational ports that are rigidly clamped to the frame must be connected to a Mechanical translational Reference block.
9.Electrical Reference:- The electrical reference block represents an electrical ground.electrical conserving ports off all blocks that are directly connected to the ground must be connected to an electrical reference block.A model with electrical elements must contain at least one electrical reference block.
10.Solver Configuration:- The solver configuration block specifies the solver parameters that your model needs before you can begin the simulation.
11. PS-Simulink Convertor:- convert physical signal into Simulink output signal.
Model Explation:-
1.The pulse generator is used to give the signal input where,Amplitude=1,period=4sec,pulse width=50%,and phase
delay=2sec.
2.After that, the input signal is converted into physical form with the use of "simulink-PS convertor" and further send to the switch of the electrical circuit.
3.The electrical circuit consists of a solenoid,a battery and a switch.one end of the solenoid is connected to the battery and its other end is connected to the switch.An electrical reference is provided in the electrical circuit.
4. The mechanical part of the solenoid is connected to an ideal translation motion sensor and mechanical translational reference.
5. The P-Port of the sensor makes a connection with the "PS-Simulink Convertor" to provide the output in signal form.Further,the convertor is connected with scope to display our output signal.
6.A solver configuration is connected to an electrical circuit to solve all paremeters before the beginning of the simulation.
scope:-1
scope:-2
Output:- we can see that the switch is closed for 2 seconds after that switch is open.
AIM:- 2
Objective:-
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.
Thermistor:- A thermistor is difend as a type of resistor whose electrical resistance varies with temperature changes.
although all resistors resistance will fluctuate slightly with temperature,a thermistor is particularly senstive to temperature changes.
Thermistor act as a pressure component in a circuit. they are an accurate ,cheap and robust way to measure temperature.while thermistors do not work well in extrremely hot or cold temperatures,they are the sensor of choice for many different applications.
SIMULINK MODEL OF OBJECTIVES:-2
The figure shows the representation of thermistor connection whisch sense the temperature of a heator and passes the signal to a switch where a thershold limit is already set . if the temperature is avbove or equal to the thershold limit.
MODEL EXPLANTION;-
1. At first ,the signal is created in "signal Builder" and further passes to "SIMULINK-PS CONVERTOR" 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 a an electric circuit where a battery,a voltage sensor ,a resistor connected parallel to the voltage sensor,an electrical reference are connected to make complete circuit.Asolver 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 it to two different "PS-SIMULINK CONVERTOR".
6.From convertor -1 ,the signal is sent to the thersold limit is set to 1.10555e-02. if the temperature is above or equal to the threshold limit. the input signal is generated with the help of a "signal Builder".
7.the switch is connected to the scope where we can see our output plot.
8.From convertor -2 , it converts the physical signal into a simulink signal and sends the voltage data from the voltage sensor to display. the display gives us the thershold value of voltage.this value is set in the switch.
OUTPUT:-
it can be seen that the value of signal is "0" from 0-10 sec because in this time the temperature was 20 degree celsius which is below 25 degree celsius means"switch off the fan". after that ,the signal vaiue gives "1" as output from "10-30 sec because in thi time the temperature was 27 degree celsius which is above 25 degree celsius "switch on the fan" . the value of the signal is again goes to "0" from 30-50 sec because in this time the tempereture was 23 degree celsius which is below 25 degree celsius means "switch off the fan".
Scope:-
NOTE:-
Simulink models of both objectives and outputs along with other dataare attached in the attachment box.