Week -2
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
AIM:
To simulate the operation of a doorbell using a solenoid. The system should demonstrate the physical movement of the plunger when the switch is closed for 2 seconds and then released.
Doorbell:
A doorbell is a siginaling device which is placed near a door to building entrance.when a visitor press a button the bell rings inside the building alert the presence of vistor.this doorbells are low voltage devices.
When you press a doorbell button a complete an electrical circuit that allows household electricity to flow through the doorbell's internal electromagnet. The magnetic field generated by the electromagnet is then used to power a mechanism that creates the doorbell sound.
Solenoid:
A solenoid is a device comprised of a coil of wire, the housing and a moveable plunger.When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in.
More simply, a solenoid converts electrical energy into mechanical work.
Simulink model for doorbell using solenoid:
The figure above is the representation of "A doorbell operated on solenoid". In this model, some blocks are used to make the working model of the doorbell. These blocks are:
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-PS Converter: Converts the unitless Simulink input signal to a Physical Signal.
3. Scope: Display signals generated during simulation.
4. Switch: Switch controlled 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. You can specify the initial position (offset) as a block parameter. The sensor is ideal since it does not account for inertia, friction, delays, energy consumption, and so on.
8. Mechanical Translational Reference: The Mechanical Translational Reference block represents a reference point, or frame, for all mechanical translational ports. All translational ports that are rigidly clamped to the frame (ground) must be connected to a Mechanical Translational Reference block.
9. Electrical Reference: The Electrical Reference block represents an electrical ground. Electrical conserving ports of all the 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 Converter: Convert physical signal into Simulink output signal.
Model Explanation:
The pulse generator is used to give the signal input where, Amplitude=1, Period=4 sec, Pulse width= 50%, and Phase delay= 2 sec.
After that, the input signal is converted into physical form with the use of Simulink-PS Converter and further send to the switch of the electrical circuit And the input signal is show below.
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.
The mechanical part of the solenoid is connected to an ideal translation motion sensor and mechanical translational reference.
The P-port of the sensor makes a connection with the PS-Simulink Converter to provide the output in signal form. Further, the converter is connected with scope to display our output signal.
A solver configuration is connected to an electrical circuit to solve all parameters before the beginning of the simulation.
RESULT:
Here we can see that the switch is closed for 2 seconds and after that switch is open. Amplitude= 0 means the switch is closed. It can also be seen that the plunger strikes after every 2 seconds.
The motion of the plunger was simulated and recorded and plotted in scope.
When the simulation is run, the model should demonstrate the following sequence of events:
1. The switch is closed, allowing electrical power to flow to the solenoid.
2. The solenoid energizes, creating a magnetic field that pulls the plunger towards the bell.
3. The plunger strikes the bell, simulating the sound of a doorbell.
4. After 2 seconds, the switch opens, cutting off power to the solenoid.
5. The magnetic field dissipates, allowing the plunger to return to its initial position.
By observing the movement of the plunger and the corresponding bell sound in the simulation, the model effectively demonstrates the operation of a doorbell triggered by a solenoid.
CONCLUSION:
The Simulink model effectively simulates a doorbell system using a solenoid. The orchestrated interaction between the electrical and mechanical components during a 2-second switch closure accurately replicates the transient behavior of a real-world doorbell, providing valuable insights into the electromechanical dynamics of the system.
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
Aim:
To design and simulate a fan control system using a thermistor for temperature sensing. The primary objectives include developing a control logic, creating a Simulink model, and verifying the system's performance through simulation. The goal is to enable the fan to operate based on specified temperature 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
SIMULINK MODEL:
EXPLANATION & RESULT:
1. To create a straightforward Fan Cooling Model using a Thermistor, Battery, Resistor, Voltmeter, and a logical switch in Simulink, we need to use Step Signal Block.
2. Initially, a Thermistor Block is added to represent the thermistor. Subsequently, a Battery Block is introduced, and the positive terminal is connected to the positive port of the Thermistor Block. For the resistor, a Resistor Block is used with a resistance value of 100 ohms, and its positive port connects to the negative port of the Thermistor Block. An Electrical Reference Block is placed near the negative terminal of the Battery Block, symbolizing the circuit's grounding.
3. A Voltage Sensor Block is connected in parallel to the Resistor Block to measure the voltage across it. The model is completed, but physical quantities are needed as signals for the Thermistor to function. To achieve this, a Controlled Temperature Source Block is utilized to generate specified temperature outputs despite varying heat flow.
4. For different temperature inputs to the Controlled Temperature Source Block, a Step Signal Block is used. The Step Signal Block provides a step change in temperature at specified times.
5. Upon running the simulation, the output of the Voltage Sensor Block, representing voltage changes concerning temperature, is connected to a Scope Block via a PS-Simulink Converter. The resulting graph reveals voltage variations corresponding to temperature changes.
6. Observing the graph, it is noted that when the temperature is 293K (0 to 10 seconds), the voltage ranges between 0.0095 and 0.055. When the temperature is 300K (10 to 30 seconds), the voltage is between 0.054 and 0.055. Similarly, when the temperature is 296K (30 to 50 seconds), the voltage is approximately 0.012.
7. To align with the objective of turning the fan on at temperatures above 25 degrees Celsius (298.15K), the threshold value for the Switch Block is adjusted to 0.025. Therefore, the logic for fan control is updated to turn the fan on when the voltage exceeds 0.025 and off when it is below this threshold.
8. Upon reviewing the updated simulation using a Scope Block, it is evident that the fan is now turned on when the temperature reaches 300K and off at other temperatures, consistent with the adjusted threshold.
9. This logic successfully achieves the objective of controlling the fan based on temperature conditions using the Step Signal Block, 0.025 threshold, and a 100-ohm resistor.
CONCLUSION:
The simulation successfully achieves the objective, with the fan turning ON when the temperature exceeds 25°C based on the updated threshold of 0.025. The 100-ohm resistor plays a crucial role in determining voltage levels across the circuit.
Drive URL:https://drive.google.com/drive/folders/1o_oK4L-rnf5zKxxNDtPfrJLRHmuywm9a?usp=sharing