Make a Simulink model of Doorbell using solenoid block

Theory:

The Doorbell model basically works on a simple principle i.e., When you press the doorbell switch, the circuit is closed and electricity flow through the solenoid which is a transducer. The magnetic field generated by the solenoid is then used to pulls the metal arm to hit the bell-producing sound.

Components:

1. Battery: A battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices such as flashlights, mobile phones, and electric cars.
   Normally 5 or 12V batteries are used for powering Doorbells
2. Solenoid: A solenoid is a type of electromagnet, which generates a controlled magnetic field through a coil wound into a tightly packed helix. The coil can be arranged to produce a uniform magnetic field in a volume of space when an electric current is passed through it.

Components used:

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. The following diagram shows how each parameter affects the waveform.
   
2. Battery:
   12V Battery is used for designing
   
3. Electrical Reference Block:
   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
   
4. Solenoid:
   This block implements the electrical and mechanical characteristics of a solenoid.
   
5. Ideal Translational Motion Sensor:
   This block measures velocity or displacement in a mechanical translational network.
   
6. Mechanical Translational Reference:
   This block represents a mechanical translational reference point, that is, a frame or ground.
   
7. Simulink-PS Converter:
   Converts the Simulink input signal to a Physical Signal or vice-versa.
   
8. Solver Configuration:
   Defines solver settings to use for simulation.
   
   

Observation:

In the above arrangement, when the switch is closed, the Solenoid receives electrical power from the battery and pulls the metal arm or plunger with the generated magnetic energy to hit the bell-producing sound.

· Make a Simulink model using a thermistor to sense the temperature of a heater & turn on or turn off the fan

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

Theory:

A thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors.

This model shows how fundamental thermal, mechanical, and electrical components can be used to model a thermistor-controlled fan. The heat-generating device starts producing 20 °C at time 0 to 10 seconds, and then at 10 to 30 seconds this increases to 27 °C and finally decreases the temperature to 23 °C from 30 to 50 seconds. The thermistor before heating up, it has low resistance thereby keeping the nominal voltage. When the Thermistor heats up, the resistance increases and in turn decreasing the voltage which is lower than the threshold voltage value causing the fan to turn On. And when the temperature lowers again, the resistance again reaches optimal value and keeping the voltage at nominal value, thus turning off the fan again.

Components:

1. Signal Builder:
   The Signal Builder block allows you to create interchangeable groups of piecewise linear signal sources and use them in a model. You can quickly switch the signal groups into and out of a model to facilitate testing. In the Signal Builder window, create signals and define the output waveforms.
   
2. Simulink-PS Converter:
   Converts the Simulink input signal to a Physical Signal or vice-versa.
   
3. Battery:
   12V Battery is used for designing
   
4. Electrical Reference Block:
   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
   
5. Thermal Reference:
   This block represents a reference point in a thermal network where the temperature is equal to absolute zero.
   
6. Solver Configuration:
   Defines solver settings to use for simulation.
   
7. Thermistor:
   thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors.
   
8. Controlled Temperature Source:
   This block represents an ideal energy source in a thermal network 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.
   
9. Temperature Sensor:
   This block measures temperature in a thermal network. There is no heat flow through the sensor. The physical signal port T reports the temperature difference across the sensor. The measurement is positive when the temperature at port A is greater than the temperature at port B.
   
10. Voltage Sensor:
    The block represents an ideal voltage sensor, that is, a device that converts voltage measured between any electrical connections into a physical signal proportional to the voltage.
    
11. Current Sensor:
    The block represents an ideal current sensor, that is, a device that converts current measured in any electrical branch into a physical signal proportional to the current.
    
12. Switch:
    Pass through input 1 when input 2 satisfies the selected criterion; otherwise, pass through input 3.
    
13. Scope:
    Display signals generated during simulation

Observation:

From the final graph, we can understand that the Fan operates only during 10-30 sec supporting the condition. This means, when the thermistor senses a temperature above 25 degC which was the threshold value, the Fan is activated else turned Off. Thus, the condition is satisfied.