Week -2

Aim:

1. To make a simulink model od Dooebell using solenoid block.
2. To use a thermistor to sense the temperature of a heater and turn on or off the fan.

Condition for doorbell:

1. Create a situation where the switch is closed for 2 seconds and then released. Observe the physical movement of the plunger.

Condition for thermistor:

1. 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, otherwise OFF.

Mechanism of doorbell:

The heart of a doorbell is an electromagnet. Electromagnets are coils of wire wrapped around a small piece of magnetic metal. When electricity passes through the wire, it creates a magnetic field around the wire. When you press a doorbell button, you complete an electrical circuit that allows household electricity to flow through the doorbell's internal electromagnet. The magnetic field generated by the electromagnet is then used to power a mechanism that creates the doorbell sound. In this challenge the aim is to create a situation where the switch is closed for 2 seconds and then released and to observe the physical movement of the plunger.

Model:

Input:

Output before optimization of solenoid:

Output after optimization of solenoid:

Blocks used:

Pulse generator:

The Pulse Generator block generates square wave pulses at regular intervals. The block waveform parameters, Amplitude, Pulse Width, Period, and Phase delay, determine the shape of the output waveform.

Battery:

This blocks models for battery.

Switch:

The switch controlled by an external physical signal. If the external physical signal PS is greater than the threshold, then the switch is closed, otherwise the switch is open.

Solenoid:

This block represents and implements the mechanical and electrical characterstics of a solenoid.

Ideal Translational Motion Sensor:

This block measures velocity or displacement in a mechanical translational network.

Mechanical Translational Reference:

This block represents a mechanical translational reference point, that is, a frame or a ground.

Solver Configuration:

The Solver Configuration block specifies the solver parameters that your model needs before you can begin simulation.

Thermistor:

Condition: 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, otherwise OFF.

Thermistor:

Thermal + Resistor = Thermistor

A thermistor is a resistance thermometer, or a resistor whose resistance is dependent on temperature.

Model:

Signal builder input:

Output:

Blocks used:

Controlled Temperature Source:

This block represents an ideal energy source in a thermal network that can maintain a controlled temperature difference regardless of the heat flow rate.

Thermistor:

A thermistor is a resistance thermometer, or a resistor whose resistance is dependent on temperature.

Voltage Sensor:

The block represents an ideal voltage sensor, that is, a device that converts voltage measured between any electrical connections into a physical signal proportional to the voltage.

Explanation:

Signal builder is used to specify the given temperature signals to controlled temperature source which is connected to a reference and a thermistor. The thermistor is connected to a battery and resistor, the resistor is then connected to a voltage source the connected to simulink blocks via a physical to simulink converter and thus the output is obtained.