Week -2
1) Simulink model of Doorbell using solenoid block.
Simulink model
Components used for the layout is pulse generator, simulink-ps converter, switch, battery,electrical reference, mechanical translational reference, solenoid, ideal translational motion sensor, solver, ps-simulink converter, scope and display.
Explanation
The pulse generator generates square waves. The specifications of pulse generator is given below.
The time period is given as two seconds and amplitude 2.
For this specification the input signal is as given below.
The input is for the time period of 10 seconds.
The switch is closed unless the external signal is greater than the threshold.
The other terminal of the switch is connected with the battery which is connected to the solenoid.
The sensor detects the movement of the solenoid plunger.
The output is then obtained from the ps-simulink converter which converts physical signal to simulink signal.
The output signal is as below.
2.Thermistor to sense the temperature of heater.
Thermistor is a resistor whose resistance depends on temperature. The principle behind its working is that when there is a change in the temerature there will be a simultaneuos change in the resistance.
Objective is to sense the temperature of the heater with thermistor.
Simulation design is given below:
Blocks used in the simulation is signal builder, controlled temperature source, thermistor, thermal reference, voltage sensor, resistor, switch, constant, scope, display and solver configuration.
The conditions are
1. 0 to 10 seconds-293 kelvin
2. 10 to 30 seconds- 300 kelvin
3. 30 to 50 seconds-296 kelvin
The input waveform from signal builder is given below.
The simulation is run for 50 seconds. And the threshold obtained for the switch is 0.01099.
The output obtained is as per required, The switch turns on only during 10 to 30 seconds when the temperature is more than 25 degree celcius.
It is clearly evident from the graph that switch is turned on between 10 and 30 seconds.