Presentation for REAL

7/29/2019 Presentation for REAL

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FACULTY OF ENGINEERING

DEPARTMENT OF ELECTRICAL

AND ELECTRONICS

ENGINEERING

BETE 3

SEKAGYA RONNIE07/U/3003/ETE/PE


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AUTOMATED LIGHT SWITCHING CONTROLSYSTEM


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ABSTRACTAn LDR sensor based on electrical and electronics

conditional circuit technology is used to develop theautomatic light switching system. The automaticlighting system will lead to energy saving and efficientusage which could benefit individuals andorganizations. Furthermore the system is developedwith the of the safety environment as a concern whenswitching on or off.

311/21/2011 supervised by Mr. Ngolobe W. Julius


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BACKGROUND For the development in a country, engineering plays a

pivotal role. By applying different engineeringprinciples to better human life.

Switching on and off of security or street lights is aburden to most establishments, this leads to extrapower costs. For example security lights at kyambogooperate all day and all night instead of only night,

same applies to Kampala street lights. The darkness controlled switch employs basic

electronics and electrical theories as well as practicalskills which we had already gained.



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Energy wastage due to themismanagement of domestic, street and

industrial lighting


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To save energy wasted on lighting by turning lights off

Minimizing on power costs for both domestic and

industrial establishments

To reduce the burden on workers to switch off the

lights daily

To provide a cheaper and long lasting option to the

current light control switching system more so for

security and street lights.

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Concentration is mostly on the application ofelectronic and electrical principles.

The basic working principle of the major componentsi.e.; LDR, Relay and comparator, is put to use



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DESIGN AND CONSTRUCTION



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DESIGN CONTINUED 24ov is stepped down to 12v AC

12v AC is rectified to 12v DC

LDR has a resistance thats inversely

proportional to the intensity of the light fallingon it.

It has a resistance of 1M when in total

darkness(maximum darkness). Has a

resistance of only about 5K during day (sufficient illumination)

L.E.D is a device that allows current flow

through it in one direction

L.E.D indicates when there's a current 911/21/2011 supervised by Mr. Ngolobe W. Julius


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DESIGN CONTINUED Suppose inverting voltage of op-amp is half the supplyvoltage

To reduce the incoming current from power, arm resistorsR3 and R4 will be 10k respectively

R1 is used to balance with LDR so as to get low level in theoutput of comparator when the light is incident fromoutside to LDR

when light is cut off, LDR has high resistance valueconsequently, non-inverting terminal voltage will increasethen inverting voltage and output of the op-amp becomes

high level(approx 10V) when output of the comparator is 10V, alarm LED must

radiate light. Since LED current is 10mA and voltageacross LED is 1.5V, the value of R5 is determined using theequation below



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JUSTIFICATIONAfter the completion of the design and construction,

the circuit is able to operate automatically

The circuit switches on at night fall(dark) and off atsunrise(when illuminated efficiently)

The sensor (LDR) controls the switching of the circuit



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ACHIEVEMENTS Reduced power expenditure

Saving of energy on supplier side(umeme)

Reduced operational expenditure arising from reducedlabor



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RECOMMENDATIONS Employ a damping circuit before the relay to reduce

chattering,

For big current loads, employ relays having contactsthat support big current loads e.g. 100A

The circuit should be put in a relatively open space andshould be covered with a transparent material

The circuit can also be modified to be used in outdooralarms by use of buzzer



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CHALLENGESAcquiring of the exact required components on the

market wasnt a walk in the park

fake components made the project rather costly Design challenges for example calculating required

resistor values

Soldering and assembly of the circuit was a challenge

to us



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CONCLUSION The final prototype of our project is constructed which

works with minimum supply of 12v. During project welearned many electrical and electronics components aswell as to work in groups.

We now understand the need for proper planning andorganized actions and we sure this project will act as abasis for future project planning and implementation.



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REFERENCES

Alldatasheet.com. Available at:

Leonardo Journal of Sciences, 2006, 9, p. 97-102 [online].Available at

Leonardo Electronic Journal of Practices and Technologies,

2006, 9, p. 55-62 [online]. Available at:

Forrest M. Mims III, EngineersMini Notebook, Volume I.Timer, Op Amp &Optoelectronic Circuits & Projects, 1

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THANK YOU

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