Week -2

1. SIMULINK MODEL FOR A DOOR BELL

AIM :-

To develop a Simulink model of a doorbell using a solenoid block to simulate a circumstance in which the switch is closed for two seconds and then released, as well as to monitor physical movement of the plunger.

DOOR BELL:-

The doorbell operates on the electromagnetic concept. It makes use of a solenoid. When the switch is closed, electricity flows into the solenoid, creating an electromagnetic field. The plunger moves as a result of electromagnetic fields and makes a sound when it collides with a bell. Door knockers are low-voltage devices.

SIMULINK MODEL:-

The switch block is controlled by an external physical signal, and if the external physical signal is larger than zero, the switch is closed; otherwise, the switch is open. The positive terminal is linked to the block, whereas the negative terminal is linked to the electrical references. We create a full electrical circuit by connecting the solenoid block to the switch and battery. The mechanical reference is linked to the common connection C. To monitor the movement of the plunger, the ideal translation sensor is linked to the solenoid block R. To obtain the output, the scope is linked to the ideal translation sensor. The pulse generator signal was converted using the Simulink Ps converter and sent into the input switch. A solenoid is installed, and a battery is attached to it. The voltage of the linked battery was set to be the same as the rated voltage of the solenoid. The switch is linked to the same circuit as well. An ideal translation motion sensor linked to the circuit measures the position of the solenoid plunger. The scope is linked in order to visualise its behaviour. To produce the required graph, the spring constant and damping value of the solenoid block were changed.

CONCLUSION OF DOOR BELL :-

Giving the pulse generator input as a time interval of 2 seconds to open and close the switch. When the switch is closed, the solenoid, block, and plunger receive electricity from the battery and move from connection R to connection C, striking the bell and producing music. The physical movement of the plunger is detected using a translational motion sensor, and the physical output is transformed into a Simulink output model, which is presented in the scope. Vibration can be decreased by lowering the spring constant value and raising the damping value.

2 :-

AIM :-

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

1. Temperature source: 20°c from 0 to 10 seconds, 27°C from 10 to 30 seconds, 23 °C from 30 to 50 seconds.

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

OBJECTIVES :- 

1. To generate a wave of temperature coefficient using suitable block.

2. To obtain the characteristics curve for change in voltage w.r.t

3. To control a DC motor for a given condition.

SIMULINK MODEL EXPLANATION :-

Inputs are sent into the Signal Builder, which is then linked to a Temperature Controlled Source in order to maintain the required temperature differential across the source. The input temperature is then sent through the thermistor.   Thermistor is connected to resistor to ensure that the thermistor is connected to the positive terminal of the resistor and that the voltage across the resistor is given by V (+) -V (-) and that the sign of the current is positive when flowing through the device from the positive to the negative terminal. This rule assures that a resistor's absorbed power is always positive. To obtain the values from the Voltage sensor, connect the positive terminals of the Voltage sensor and the Resistor. Switch is attached to the voltage sensor's output terminal. Using the Switch Parameter, indicate that the fan must be turned on if the temperature exceeds 250C and off otherwise. Output is successfully executed by connecting with scope in accordance with the specified criteria.

CONCLUSION :-

This clearly illustrates that from 0 to 10 seconds, the fan is turned off since the temperature is 293 degrees Celsius, which is less than 298 degrees Celsius. After 10 seconds, the temperature rises to 300 degrees Celsius, causing the fan to activate since the temperature surpasses 298 degrees Celsius. The fan was turned off after 30 seconds because the temperature had dropped to 296 degrees Celsius.

Hence the given conditions are satisfied using repeating sequence stair and switch block