Week -2

Aim:-

1.Make a Simulink model of Doorbell using a 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. Assume remaining parameters.

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

Solution:-

1. Doorbell

Link of file:- https://drive.google.com/file/d/1CLm_VsfQiV76-s42Flo1FOLB3OXiUw3l/view?usp=sharing

Simulink model has been shown above for a doorbell system. All the block has been shown with the name. Here I have used Pulse Generator to create a cycle of 4 sec, in this 4 sec, for 2 sec the switch will be closed, and for 2 sec the switch will be open. The parameters of this block have been shown below.

Output:-

The output of this Simulink Modal can be extracted from a scope that is attached to a translational motion sensor. We can also see the value of the change in position in the display block.

2. Thermistor for a heater

File link:- https://drive.google.com/file/d/1W826KZ4X2qa3slaqx3K37bh2Yu20Wk_2/view?usp=sharing

Here, in the above picture, a Simulink model has been shown for a thermistor to sense the temperature of the heater and switch on the fan if the temperature is above 25 degrees celsius. As we can understand the direction and workflow from the model snap. I would like to focus on input and output. Here the input is a Signal builder that is creating a signal for a controlled temperature source blockset according to the input temperature and time.

Input Signal Builder:-

For 0 to 10 sec, temperature is 293 K (Converting 20 degree into kelvin 273+20 = 293 K),

For 10 to 30 sec, temperature is 300 K (Converting 27 degree into kelvin 273+27 = 300 K)

For 30 to 50 sec, temperature is 296 K (Converting 23 degree into kelvin 273+23 = 296 K)

Output:-

As we can see here I have used a switch block that takes input for a threshold value and here it is in voltage. So, I needed to find the value of voltage with respect to 25-degree celsius and for that, I used a constant(Value is 298 for 25 degrees celsius) block at the input, and the voltage is displayed with respect to 298. This voltage output I used in the switch for threshold value and input constant is replaced with the signal builder. The output is shown below.