The document discusses several ways to optimize energy usage and conserve energy through automatic control systems using sensors. It describes projects using IR sensors to automatically turn lights and fans on/off based on occupancy. Another project uses an LDR sensor to turn street lights off during the day. A third project uses an MQ-135 gas sensor and Arduino to automatically turn an exhaust fan on when detecting smoke in the kitchen. The document promotes conserving energy through automatic control systems using various sensors.

2. Introduction:
Need for Conservation of Energy:
• Increasing demand for power has increased the use of fossil fuels,
polluting the environment.
• Thus efficient use of energy and its conservation is of paramount
importance.
• One unit of energy saved at the consumption level reduces the need
for fresh capacity creation by 2.5 times to 3 times.
• Energy consumption in the residential sector accounts for a
significant proportion of national usage.
• Optimization of energy usage in the home can then be mutually
beneficial to the homeowner, the electricity provider, and the
environment.
• The homeowners benefit by a reduction in their electricity costs
through optimization of energy usage where applicable.
• The various alternatives that can be used are conventional sources of
energy namely solar energy, wind energy, tidal energy, geothermal
energy etc.

3. •Problem statement:
Wastage of electricity in our home, school or colleges due to negligence
in switching off fans and lights.
•Approach:
We solve this by making use of IR transmitter-receiver
pair to switch ON and OFF lights and fans automatically
sensing the presence of people.

4. Working :
• IR Transmitter-receiver (TSOP 1738) pair is placed on the door frame ,in
front of each other.
• If a person enters the room then first receiver will cut and then second
receiver will cut.
• The microcontroller will receive a pulse from receiver1 and receiver2 and
increment counter.
• The microcontroller sends a signal to the relay to switch on the lights and
fan.
• If any person leaves the room then second receiver will cut and then first
receiver will cut, counter is decremented.
• When number of persons inside the room is zero, lights and fan inside the
room is turned off using the relay.

5. •Problem Statement:
We have often noticed that even the in the presence of adequate
sunlight the street/staircase lights are not turned OFF, mainly due to
human negligence.
•Approach:
We can overcome this by making use of a sensor
which uses electricity only in the absence of sunlight.
This can save electricity to a large extent.

6. WORKING:
•When there is darkness, the sensor circuit gets activated and switches
ON and light turns off and when there is sunlight the street light gets
OFF.
•IC 555 Timer is used as a comparator, output goes high when the
voltage at trigger pin is less than 1/3rd of supply voltage.
•LDR is used which has resistance whose value depends on the
brightness of the light which is falling on it. It has resistance of about 1
mega ohm when in total darkness, but a resistance of only about 5k
ohms when brightness illuminated
•The output of potential divider circuit(LDR and variable resistance) is
given to trigger pin of IC555
•.As soon as LDR gets dark the voltage of trigger pin drops 1/3rd of the
supply voltage and output gets high and LED.

7. •APPROACH:
We overcome this by using smoke detector MQ 135 which senses
the smoke and actuates the exhaust fan automatically till the time it’s
required.
•Problem Statement:
While working in the kitchen we often forget to switch OFF the
exhaust fan even when the smoke has subsided.

8. WORKING
• MQ-135 gas Sensor is used to detect gas NH3, NOx , alcohol, Benzene,
smoke, CO2.
• The enveloped MQ-135 has 6 Pins, 4 of which are used to fetch signals,
while the other two are used to provide heating current.
• The sensor is interfaced to an arduino board which gives power supply to
pin H.
• The resistance value between A and B varies in the range of 30KΩ to
200KΩ with the change in the concentration of gases.
• The analog signal to A0 of the arduino board is given from pin B of the
sensor.
• The changes in the voltage levels are displayed on a Serial Monitor which
reflects the concentration of gases.
• The Arduino board is programmed such that whenever a value greater
than the threshold value of 500 is detected, the output Pin 13 of the
Arduino goes high and the exhaust fan is switched on.

10. Whatis Solar?
• Solar energy is obtained by the conversion of
sunlight into electricity, either directly using
photovoltaics(PV), or indirectly using concentrated
solar power(CSP).
• Concentrated solar power systems uses lenses or
mirrors and tracking systems to focus a large area of
sunlight into a small beam.
• Photovoltaic cells convert light into electric current
using the photovoltaic effect.
• Solar Thermal: Harnessing solar energy to thermal
energy (heat).
• Concentrated Solar Power: Use of lens or mirror to
focus large area of sunlight into a small beam.

11. • The abundance of Solar Energy.
• You don’t pay for sunlight.
• Solar energy is getting more cost effective.
• Solar energy is non-polluting.
• Accessibility of solar power in remote locations.
• Solar energy systems are virtually maintenance free.

12. • High initial capital outlay.
• Dubious reliability.
• Availability of sunlight.
• Polluting materials used in solar panels.
• The efficiency question.

13. Applications
• Rural electrification
• Solar lamps and lighting
• Agricultural support
• Solar water heaters and cookers

14. FUTUREOFENERGY
• Though it cannot completely replace traditional
energy sources, the future of solar energy is still bright.
• For most part of the year, we are blessed with
abundant sunshine.
• While the country still lags behind the western world,
India is slowly waking up to the possibilities of using the
sun’s energy to the maximum.
• Not just in the industrial and commercial
establishments, but in homes too, spurred by the
Jawaharlal Nehru National Solar Mission which has an
ambitious target of deploying 20,000 MW of grid
connected solar power by 2020 and 2,000 MW of off-grid
solar power by
2022.

15. Challengeahead
Assuming an average home requires 200 units of
electricity per month, and a reasonable tariff of
Rs. 5 per unit of electricity, the average home pays
Rs. 12,000 per year for electricity. However, a
solar power system costs Rs. 1.2 Lakh. This means
that the system will not pay itself back for up
to 10 years! Thus, even though there may be long-
term savings for a family with solar power, most
families will prefer to continue using electricity from a
utility company. We need to significantly
disrupt the cost of solar power here.

16. Government Support
•The government of India is promoting the use of solar energy through
various strategies. In the budget for 2010/11, the government has
announced an allocation of 1000 crore towards the Jawaharlal Nehru
National Solar Mission and the establishment of a clean energy fund.
• This new budget has also encouraged private solar companies by
reducing customs duty on solar panels by 5% and exempting excise duty
on solar photovoltaic panels. This is expected to reduce the cost of a
roof-top solar panel installation by 15–20%.
• Additionally, the government has initiated a Renewable Energy
Certificate (REC)scheme, which is designed to drive investment in low-
carbon energy projects.
• The Ministry of New and Renewable Energy provides 70 percent subsidy
on the installation cost of a solar photovoltaic power plant in North-East
states and 30 percentage subsidy on other regions.