The document summarizes a presentation on a hollow flashlight invented by Ann Makosinski that is powered by body heat through the use of Peltier tiles. The flashlight uses the temperature difference between a person's hand and the ambient air to generate enough voltage to power an LED light through the Peltier effect. It can provide a steady beam of light for 20 minutes and does not require batteries, making it useful for areas without reliable power sources. While it has limitations like only operating for short periods of time, the design demonstrates the potential of harnessing body heat as an alternative energy source for small devices.

1. A PRESENTATION ON
HOLLOW FLASHLIGHT
BY
AISHWARYA K. PATIL

2. INTRODUCTION
 The human body, at any given moment, produces
energy equivalent to 100 watt light bulb
 We are wasting our energy—energy that can be used
to power a light bulb
 It's this line of thinking that led a 16 year old to invent
the first flashlight powered entirely by body heat.

3. Scotch whisky segment is
growing
Revenue growth in W&M
expected
IDEA BEHIND
Ann Makosinski of Canada had invented
HOLLOW FLASHLIGHT, which won the 15-16
age group category of the Google Science Fair.
The basic principle of the Hollow Flashlight is
Peltier Effect .This flashlight runs on four
Peltier tiles, which convert heat into energy
using the temperature differential between a
person’s hand and the ambient air.

4. PRINCIPLE
• The thermoelectric effect is the direct conversion of
temperature differences to electric voltage and vice
versa.
• A thermoelectric device creates voltage when there is a
different temperature on each side.
• Conversely, when a voltage is applied to it, it creates a
temperature difference.
• At the atomic scale, an applied temperature gradient
causes charge carriers in the material to diffuse from the
hot side to the cold side.

5. PHYSICAL DESIGN
LED light
(can’t see)
Opening where
human hand goes
on peltier tiles PVC pipe
Electric
circuit
Aluminium : a
great heat sink
Peltier Tiles

6. INITIAL DESIGN
• Peltier tiles were tested to see if they could produce
sufficient power to light an LED.
• The power was no problem but getting the needed voltage
was, as the tiles did not generate enough of the voltage
needed.
• The transformer was used to rise the voltage

8. •The Peltier effect is the presence of heating or
cooling at an electrified junction of two
different conductors
•When a current is made to flow through a
junction between two conductors A and B, heat
may be generated (or removed) at the junction.
PELTIER EFFECT

9. VOLTAGE BOOSTER CIRCUIT

10. WORKING
• The tiles are fixed to the outside of a hollow tube
• One side of the tile is heated by the warmth of the
hand, while air flowing through the hollow tube
helps keep the other side cool.
• The electricity generated by the temperature
differential between either side of the tile powers
the LED light

11. BETTER WORKING
• Flashlight work better when the difference between
the ambient temperature and body temperature is
greater.
• So while the flashlights worked with an air
temperature of 10°C (50° F), they emitted more light
with the air temperature at 5°C (41° F).
• It is capable to maintain a steady beam of light for 20
minutes, even in the warmer temperature

12. • Saves individual money from continuously paying to buy the batteries
when they are used up
•It does not use any moving parts as peltier tiles are used which are
compact. Hence, less maintenance needed
• Reduce the use of single use batteries that are thrown in landfills,
which reduce the negative effect of batteries on environment.
• Will always work ,with compared to battery powered flashlights which
die after long time use.
ADVANTAGES

13. DISADVANTAGES
01
Limited time. Can work only for 20
minutes
03If temperature diference is less than 5 degree
celsius then it will not work
02
There must be greater temperature differential between
the temperature of hand and ambient air to shine at fullest
potential

14. APPLICATIONS
•It can be used in rural areas where there no power for
long hours of day. It would help students to study in dark.
•Researchers look into ways to capture excess body heat
as a means of powering devices like hearing aids and
pacemaker
•Her hollow flashlight to be manufactured and sold to
interested customers
•Imagine her design being used in classrooms to power
schools, on wireless medical sensors, and being used to
charge cellphones

15. CONCLUSION
• The final prototype cost her US$26, but Makosinski believes the
product could be produced in mass quantities for less
• This technology has a lot of potential and it can be improvised
to increase efficiency of flashlight and widen its scope
• Even with all thermal and power conversion losses , there was
still enough power in palm to provide usable light. Hence, it is
used where not high efficiency but long life needed
• By taking inspiration from HOLLOW FLASHLIGHT other
alternatives of electricity can be harnessed

16. For your attention!
Any questions?