Week -2

• Aim

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.

• Conditions:

• Switch is closed for 2 seconds and then released.

• Blocks used in model:-

• Pulse Generator
• Switch Battery
• Solenoid
• Ideal Translational Motion Sensor
• Mechanical Translational Reference
• Electrical Reference
• Scope

• Model Explanation:-

• A puse generator is given as input with the following specifications.
• The condition was that the bell is engaged for 2 s and then released. Same was implemented by giving period as 10 seconds and pulse width assimulation seconds, ie, 2 seconds Phase delay was given as 2 seconds, so the simulation starts from the unengaged condition of switch.
• The signal from the pulse generator was converted using a simulink-PS converter and is given as the input to the switch.
• A Solenoid is introduced and battery is connected to it.
• The voltage of the battery connected was made as the same as that of the rated voltage of the solenoid. The Switch is also connected to the same circuit.
• The position of solenoid plunger is measured using an ideal translational motion sensor connected to the circuit. Initial position was set to 5mm in translational motion sensor. Both mechanical and electrical references were connected to the respective circuits.
• The output from the ideal translational motion sensor is converted using a PS-Simulink converter and is given to the scope to display the results.
• A scope was also connected to the input to visualize its behaviour. The spring constant and damping parameters of the solenoid block was altered to obtain desired graph.
• The simulation was run for 10 seconds and the result obtained is shown above. It can be observed that, at each 2s interval the bell is ringing

• RESULTS:-

• The solenoid's damping effect is pulling the plunger back to its mean position after the the input signal is switched on.
• The voltage input of the solenoid should match that of battery, therfore the 12V input is given.

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

• Block use in model:-

• Signal builder
• Control temperature Source
• Thermistor
• Dc source
• Resister
• Voltage sensor
• Switch (3port)
• Control voltage source
• Dc motor
• Ideal rotational motion sensor
• Electrical reference
• Mechanical rotational refrence