Week -2

1. Doorbell using Solenoid.

Simulink Model -

Output -

Input Signal -

Description -

To depict the door bell solenoid is used. The purpose of the solenoid is that its port will either move towards or away from the reference port. Battery is used to power the solenoid and the switch is used which will indicate the press of the doorbell. The input signal is shown above where the switch is made on for 2 seconds as asked in the question. The output signal indicates the variation in the position as seen in the graph. Change in the position is very small(in mm.). In practical case the motion sensor at the output can be replaced by bell and hammer system which will produce the sound.

2. Thermistor Application -

In above model constant block is used which measures the voltage at 25 degree Celcius. That value will be the threshold for the switch as we can see in the following Model.

Model -

Input -

Output -

Description -

Signal builder block is used for generating the required input as asked in the question. Voltage Sensor is used across the resistor which will measure the potential difference as the temperature changes. In the first model display is used which was used to get the voltage when the temperatue is 25 degree. That value is the given as threshold for a switch as seen in the 2nd Model. The output graph shows that the output is high during time 10s to 30s. As we see in the input graph the temperature is more that 25 degrees(greater than 298.15 kelvin) during that time which justifies the high output. To make it simpler graph is used instead of fan. output 1 indicates the on state of fan and 0 indicates the off state.Temperature is given in kelvin so the parameters are adjusted as per kelvin scale.