Light Sensors

Light sensors provide a sensitive measurement of light and are often used as non-intrusive motion sensors. Typical light sensors include photodiodes, phototransistors, photoresistors, infrared detectors, etc. Example project ideas:

• Devise an experiment to validate the inverse square law of light decay.
• Determine the effectiveness of different light insulating materials and light reflecting materials.
• Develop prototype systems such as home/office theft alarm, marine collision detection, and automated door opener, etc., using a light sensor and an appropriate logic algorithm.

Sound Sensors

A sound sensor measures the fluctuation in air pressure to provide a measure of amplitude and frequency of sound waves. Example project ideas:

• Perform noise pollution studies in the proximity of busy streets, train tracks, airports, etc.
• Determine the effectiveness of different materials in absorbing sound of different amplitude/frequency.
• Demonstrate the feasibility of destructive interference techniques for noise cancellation.

Thermal Sensors

A thermal sensor measures the fluctuation of either temperature or heat flux in different media. Typical thermal sensors include thermistors, resistance temperature devices (RTDs), thermocouples, thermopiles, etc. Example project ideas:

• Design a prototype experiment, using an air and a carbon dioxide filled enclosure, a lamp, and temperature sensors, to validate the phenomenon of global warming.
• Design an experiment to validate Newton's Law of Cooling, which states that the rate of heat transfer from a hot to cold body is proportional to their temperature difference.
• Using heat flux and temperature sensors distributed throughout the interior and exterior of a house, which is subjected to extreme exterior weather conditions, measure the heat loss from specific locations of the house and recommend appropriate action.

Feedback Control

In feedback control, the error between desired output and actual output of a system is used to compute and apply a corrective action. Example project ideas:

• Develop an automatic liquid dispensing machine, which begins dispensing liquid once a cup is placed on it and stops when the liquid level in the cup is about to violate safety limit.
• Develop a prototype automatic headlight control system for automobiles, which turns the light on/off by continuously monitoring the ambient light condition.
• Develop an indoor climate control system, which controls heating and air conditioning units to maintain a comfortable environment.
• Develop a prototype device to control indoor lights when window blinds are opened/closed.

Voltage Divider

Numerous sensor designs exploit the "Voltage Division Law" to provide the measurement of a physical quantity by measuring the voltage across a resistor. Example project ideas:

1) Develop a comprehensive fault detection system for automobiles using the voltage divider circuit and appropriate resistive sensors. For example:

• Using a resistive temperature sensor, monitor the engine temperature.
• Using a resistive pressure sensor, monitor the air pressure in tires and pressure in hydraulic lines of a braking system.
• Using a thermistor, develop a sensor to warn the driver of icy road condition.

2) Develop subsystems for home monitoring/automation that exploit the voltage divider circuit and appropriate resistive sensors. For example:

• Monitoring the ambient light intensity to turn on (off) the lights at sunset (sunrise)
• Monitoring the activities of inhabitants in a house to control heating/cooling systems
• Monitoring unauthorized entry in the house