This ppt gives a basic idea on how piezoelectric sensors work,and how they can be used for generating electricity.It also includes a circuit diagram on how the connections need to be made

1. HARNESSING OF POWER ON
HIGHWAYS AND RAILWAYS USING
PIEZOELECTRIC SENSORS

2. INTRODUCTION
• Piezoelectricity (also called the piezoelectric effect) is the appearance of an
electrical potential (a voltage, in other words) across the sides of a crystal
when you subject it to mechanical stress (by squeezing it).
Fig.1 Fig.2 Fig.3

3. PRINCIPLE
• A piezoelectric sensor is a device that uses the piezoelectric effect, to
measure changes in pressure, acceleration, temperature, strain, or force by
converting them to an electrical charge. The crystal is usually made of quartz,
tourmaline, Rochelle salt.
• In practice, the crystal becomes a kind of tiny battery with a positive charge
on one face and a negative charge on the opposite face; current flows if we
connect the two faces together to make a circuit. By placing this arrangement
under highways or railways; large amount of electricity can be obtained; due
to the innumerable vibrations produced.

4. HOW PIEZOELECTRICITY WORKS
• Normally, the charges in a piezoelectric crystal are exactly balanced, even if they're
not symmetrically arranged.
• The effects of the charges exactly cancel out, leaving no net charge on the crystal
faces. (More specifically, the electric dipole moments—vector lines separating
opposite charges—exactly cancel one another out.)
• If we squeeze the crystal , we force the charges out of balance.
• Now the effects of the charges (their dipole moments) no longer cancel one
another out and net positive and negative charges appear on opposite crystal faces.
By squeezing the crystal, we've produced a voltage across its opposite faces—and
that's piezoelectricity!

5. ROAD CROSS-SECTION

6. CIRCUIT DIAGRAM FOR A
PIEZOELECTRIC GENERATOR
Fig.4

7. ADVANTAGES
• Running cost is low.
• It’s efficiency doesn’t decrease with its lifetime.
• The same material can be used for innumerable times.
• Skilled professional’s required is less.
• Electricity can be obtained throughout the year without any disturbance.

8. REFERENCES
FIGURES:
1. https://en.wikipedia.org/wiki/Piezoelectric_sensor
2. https://en.wikipedia.org/wiki/Piezoelectric_sensor
3. https://www.sparkfun.com/products/10293
4. https://www.teachengineering.org/activities/view/uoh_piezo_lesson01_ac
tivity1

9. REFERENCES
WEBSITES:
1. https://ccrma.stanford.edu/CCRMA/Courses/252/sensors/node7.html
2. http://newatlas.com/piezoelectric-road-harvests-traffic-energy-to-generate-
electricity/10568/
3. https://en.wikipedia.org/wiki/Piezoelectric_sensor
4. http://www.explainthatstuff.com/piezoelectricity.html
5. https://www.teachengineering.org/activities/view/uoh_piezo_lesson01_activity1

10. THANK YOU!!!
BY,
ROHITH RAJ.S