Week -2

Aim:To make a simulink model of doorbell using a solenoid value by simulink block of thermisitor to sense the temperature of the heater and turn ON or OFF as per given temperature conditions.

Doorbell using Solenoid Valve:

The solenoid is an electromagnet, on passing current through wires connected by solenoid induces a magnetic filed around the solenoid valve and induced magntic field attracts the conducting materials, this principle is used in doorbell. when the switch button of Doorbell is pressed, the current passing through wire and plunger in the bell gets an actuted position and makes sound, then finally comes rest.

in this simulink model i have used pulse generator as input block, the pulse is every 0.2 seconds is ON.

As we want the circuit to be close only in the interval of 0.2 seconds a switch block is used. The switch block has a threshold value of 0.8, the threshold of pulse generator is 1. The switch will only close if the value of the threshold more than 0.8, This is connected to solenoid block which contains the plunger arrangment. Initially the plunger is away from C and the Value X is 5 mm and when the plunger is near C the value x is 0 mm is sensed by ideal motion sensor.

Fan Controlled by the thermistor

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

0-10 sec 20 Degree C

10-30 Sec 27 Degree C

30-50 sec 30 Degree C

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

Thermistor Simulink Block

The requirement is such that, the fan should be turned on when the temperature sensed is greater than 25 degree C. To fulfill objective we use a voltmeter to find the voltage of the circuit at temperature differnce. for 25 degree C the voltage found 0.23V.