Week -2

AIM:- To make a simulink model of doorbell using solenoid block and to make a simulink model of a thermistor to sense the temperature of heater and turn on or turn off the fan.

Software Required:- MATLAB(simulink).

1) Doorbell using solenoid:- The solenoidis an electromagnet passing current through the conducting wires a magnetic field is generated around it which attracts magnetic materials. This phenomenon is used in the bell. When the switch of the bell is pressed the current passes through the circuit, exciting the electromagnet and pulling the plunger towards the metal portion. This produces a ringing sound.

Simulink Diagram:- The Doorbell uses an electromagnet called sa solenoid. A solenoid is an electromagnet where the coiled wire surrounds a metal piston. The piston contains magnetically conductive metal, so it can be moved backwards or forward by the electromagnetic field. The total time for signal is set for 10 seconds and pulse generated for every 2 seconds The ideal transformer motion sensor is used to monitor the position and velocity of plunger which is nothing but the piston for each pulse. Electrical and mechanical reference were given to each mechanical and electrical systems. A solver is provided to compute the states of thr model during simulation or code generation.

In the simulink model i have used a pulse generator block as an input. the pulse is such that, every 2 seconds its ON.

Result:-

In the simulink model i have used a pulse generator block as an input. The pulse is such that, every 2 seconds its ON. In the above figure the cycle repeats for 2 second.

There are some kinds of response having in the graph when switch is closed due to electromagnetic interference.

2) Fan controlled by thermistor:-

Thermistor is a sensor which is used to measure the temperature of the surrounding by comparing it with a known temperature and resistance values. The conditions are:-

0 - 10 seconds 20 degree celsius

10 - 30 seconds 27 degree celsius

30 - 50 seconds 23 degree celsius

The input signal corresponding to the above parameters is given using a signal builder block.

The input signal corresponding to the above parameter is given using a signal builder block.

for finding the threshold value we have to create a model like shwn in below. our threshold value is 0.012 approx.

Result:-

From the switch output we can see that, only output is between 10-30 seconds as the temperature is greater than 25 degree celsius. So this output can be given to fan for the simulation.