International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
INTELLIGENT ELECTRONIC SWITCH (IES) FOR ENERGY SAVINGS
O. Obajemu, P. O. Oluseyi, T. O. Akinbulire, C. O. A. Awosope and M. Odekunle
Department of Electrical/Electronics Engineering, Faculty of Engineering, University of Lagos, Lagos
ABSTRACT
This paper discusses the intelligent electronic switch (IES) as an important electrical energy conservation
tool. The intelligent electric switch will use photoelectric beams to detect and keep count of the occupants of
a room, keeping the lights on until the last person leaves. This system is different from the available
technologies in the sense that it displays the number of people in the room and eliminates every form of
false counts through carefully designed programming. The simulation of the IES circuit was realized using
Microchip’s Programmable Integrated Circuit Laboratory (MPLAB) and PROTEUS Visual System
Modelling (VSM).
Keywords: Energy, illumination, cost, integrated circuit, conservation.
1.0 INTRODUCTION
With the current electricity shortage, energy conservation has become an area of active research. Although it
makes up about 17% of all electricity consumed nationally, lighting is often overlooked as a potential area
of interest for energy conservation (USDOE, 2009).
Energy is an inextricable part of a nation’s security and self-sufficiency. This is because of the fact
that the national economic development is closely related to it, as matter of fact, the human development is
often correlated to the energy per capita consumption of the nations. Thus, every modern society has been
making several efforts to address the issue of development with respect to adequate continuous availability
of energy to the citizenry, as well as supplying it at affordable prices.
So the Government of Nigeria’s desired and consummated project in the aspect of increasing the
amount of generated electricity is justified (J-F Akinbami & A. Lawal, 2003).However, it is quite appalling
to note that a very substantial amount of this generated electricity is wasted. According to the Green Seal, a
staggering 35% of electricity supplied to homes and offices are wasted (Green seal, 2001). These wastages
are as a result of daily practices which are usually taken for granted, to mention but few includes leaving
light on when it is not needed or relevant in providing further illumination, incessant opening of the doors of
refrigerators etc Conservation, 2009). Wasting electricity is analogous to using leaking bucket to fetch
water. At the end of the day, it is not cost-effective and it is wasteful, hence, the policy should not only seek
to improve electricity supply but should also commit effort to the means of energy conservation.
One aspect of power consumption typically overlooked and underestimated is lighting. Interior
lighting accounts for over 17% of all electricity used in the world each year. Therefore, a lot of electrical
power can be conserved by the simple act of turning off the light bulbs when they are not needed for
illumination (EIA, 2009).
It is the intention of this work to simulate the results from the implementation of the IES technology
to conserve electric power consumption on the account of illumination lamps and light bulbs.
2.0 OBJECTIVES OF THE STUDY
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International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
As stated earlier, the electric lighting or artificial lighting consumes significant amount of total
electrical energy consumed globally. In homes and offices, from 20 to 50 percent of total energy consumed
is due to lighting. Most importantly, for some buildings over 90 percent of lighting energy consumed can be
an unnecessary expense through over-illumination (Conservation, 2009). The cost of that lighting can be
substantial. A single 100W light bulb used for just 6 hours in a day can cost more than 10 dollars per year to
the user (at about 10 cents / kWh). Thus lighting represents a critical component of energy use today that
needs to be addressed in line with energy conservation, especially in large office buildings where there are
many alternatives means of energy utilization for providing illumination. So the simple act of turning off
those 60W bulbs when it is not necessary to turn it on can save thousands of Dollars annually.
Fig 1: Manual Control Vs Sensor Control
This idea of energy conservation can be actualized by manual control as well as electronic control of the
electric light switches. Figure 1 depicts the graphical illustration of both concepts of lighting control. From
this graph it can be observed that the manual control of the lights by a switch leads a higher percentage
consumption than lights controlled by sensors which presents a much lower percentage of energy
consumption (Green Seal, 2009). There are several types of sensor control technology that are currently in
use for this purpose.
2.1 Available Sensor Technologies
There are several well-known devices currently being employed to assist in the control of the
electricity wastage through lighting (Lowe & Johnson, 2001) Some of these technologies are:
1.
Infrared Motion Sensors
2.
Ultrasonic Sensors
3.
Audio Sensors.
These devices employ sensor technology. With the aid of this technology, it becomes possible to
monitor when a person is present in a room or not. These sensors are coupled with relays that switch ON or
OFF the lights with regard to some set of conditions. If after some time, the sensor fails to sense any motion
or sound in the room, it triggers the relay which in turn puts off the electric light bulbs in the room. It is
observed that these automatic light controls are prone to false triggers (Occupant sensor, 2009) A need has
been identified for a technology that could automatically control lights but without false triggers, On this note
the IES technology is developed to employ the sensor technology which operates in a more precise manner
to efficiently eliminate any form of false triggers.
The Intelligent Electric Switch (IES) technology is designed to meet the following criteria so as to ensure its
feasibility and market viability namely:
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International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
1. It should operate at the rated voltage of the mains i.e. 240VAC.
2. It should continue in operation even after power failure, hence the provision of an interrupted power
supply as a bank of batteries.
3. The counter must not reset after power failure. Hence, the need for a flash Electrically Erasable
Programmable Read Only Memory Programmable Integrated Circuit (EEPROM PIC) microcontroller.
4. It must be small in size.
5. It must be easy to install.
6. It must be reliable, fail-safe and have a long life span.
7. It must be affordable and cost effective.
8. It must work in any private or public building.
3.0 DESIGN APPROACH
Figure 2 shows the block diagram of the Intelligent Electric Switch (IES) technology. As can be observed
from the picture, interfacing signals to the PIC microcontroller from the various components require
carefully designed circuitry using the appropriate values of circuit parameters for its operation.
Signal from
Photo-sensor
LCD to
Display
MicroController
Inputs
switch for
Lighting
Reset
Reset
Button
Relay
Fig. 2: The Block Diagram of the IES technology
Further from figure 2, it is obvious that the diagram of the IES technology can be divided into 4
broad units namely;
1. The power supply unit (PSU)
2. The input unit (IU)
3. The output unit (OU)
4. The control unit (CU)
Each of these units is discussed in turn below.
3.1 The Power Supply Unit (PSU)
3
International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
The essence of the power supply unit is to convert the mains voltage which is about 240VAC to the voltage
required by the digital components of this project. i.e. +5VDC. Obtaining +5 VDC from 240VAC requires
scaling down the voltage and converting alternating current to direct current using the dc rectifier circuit. In
addition, most power supplies include a voltage regulator component that ensures that the circuit voltage is
exactly +5 volts (Boylestad & Nashelsky, 2006).
3.2 The Input Unit (IU)
The input unit of the IES technology is the unit that activates the control unit in order for the latter to
discriminative select the type of operation to perform at any point in time. The major parts of the input unit
are:
1. The beams
2. The reset counter button
3. The manual switch override
3.2.1 The beams
The beams used in this project will be retroflective in nature. This will consist of two beams that are
implemented as a transmitter and receiver respectively. When one beam is hit, there will be a signal sent to
the control unit, which will indicate the entrance or exit of persons into the room (Sanchez & Canton, 2007).
The beams selected for this project are Omron’s M18 Cylinder Photoelectric beams. Each has a
characteristic built-in amplifier with ability for a long detection distance of 7m. It is also provided with DC
switching module placed in connectors for easy maintenance. This arrangement operates over a wide range
of voltage values, from 10 to 30 VDC.
Fig. 3: Schematic of Beams
As it can be seen in Figure 3, the beam is connected to the PIC as well as with the “Load”. However the
10V signal provided by the beam will have to be passed across a voltage divider which in turn provides the
5V signal needed for operation of the PIC (Hay, 1941).
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International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
3.2.2 The Reset Counter Button
The reset counter button is a switch whose duty is simply to reset the counter to zero. This is particularly
useful when false count has been detected. Though false counting on the IES technology would be a rare
phenomenon but as a means ensuring a very efficient service, provision has been made for any form of
occurrence of it. The operator of the IES would simply wait for when there is no body remaining in the
room or building and simply reset the counter to zero.
3.2.3 The Manual Switch Override (MSO)
The manual switch override is one of the many features of the IES technology that makes it fail-safe to a
certain extent. The MSO takes into consideration the fact that unlit occupancy might occur in the operations
of the IES due to several reasons. Thus faulty operations in the IES could be noticed especially after so
many years of IES usage. The MSO is a switch that bypasses the operation of the IES and allows the user or
operator to operate the light switches manually.
3.3 The Output Unit (OU)
The main component of the output unit is the liquid crystal display (LCD). The LCD used in this project is
the Hitachi based HD44780. This displays the number of people in the room (Sanchez & Canton, 2007).
3.4 The Control Unit (CU)
The control unit is the main and most important unit of the IES. It coordinates the whole system; it is for this
reason that it is accurately termed ‘intelligent’. The microcontroller is in essence the control unit. It controls
the switches, the output devices and all other peripheral components. The microcontroller as the workhorse
of the project is programmed (using assembly MPLAB language) by the programmer. The microcontroller
selected for the IES technology is the PIC 16F877 from microchip (Lowe & Johnson, 2001).
This selection of the microcontroller will allow the goal of reduction in power consumption, size, cost,
adaptability, reliability and flexibility become achievable.
3.5 Principle of operation of the IES technology
As mentioned earlier, the PIC microcontroller 16F877 is the workhorse of the IES technology. Thus, it
makes the intelligent decisions for the switching system in two (2) units of infra-red beams serve as the two
(2) inputs to the microcontroller. With the beams placed at the door separated from each other by a distance
of 10cm then it becomes easy for the microcontroller to determine which of the beams is crossed first and
which one reconnects first.
The microcontroller operates at a clock frequency of 4MHz, and this frequency makes it very appropriate
for the system to actuate when the infra red beams have been crossed (Hay, 1941). The microcontroller has
no output whenever only one of the beams is crossed. However, when both beams are crossed, the
microcontroller waits for the beams to reconnect before deciding whether to increment or decrement the
internal counter embedded in the microcontroller. This decision is determined by a number of factors which
include:
1. Are the two beams crossed?
5
International Conference on Innovations in Engineering and Technology (IET 2011), August 8th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O. A. AWOSOPE and M. ODEKUNLE
2. If the two beams are crossed, which of the beams was crossed first?
3. Have the two beams reconnected back?
4. Which of the two beams reconnects first?
Based on the answers to these questions, the microcontroller produces a result which is displayed on the
LCD in terms of number of people in the room. This action prompts the switching ON or OFF of the electric
bulbs in the room. The flow chart diagram of the activities of the IES control unit is shown in figure 4.
Start
Test
Beams
No Beam
Crossed
Beam #1
Crossed
Beam #2
Crossed
Test
Reconnect
No
Reconnect
Test
Reconnect
No
Reconnect
Beam #1
Beam#2
Beam #1
Beam#2
Decrement
Counter
Increment
Counter
Display
LCD
Test
Counter
Counter =
0
Switch
OFF
Counter >
0
Switch
ON
Stop
Fig 4: Program flow chart
Figure 4 illustrates the flow chart of the program that runs the microcontroller. The program starts by testing
the beams and then takes appropriate actions depending on the states of the beams, viz:
1.
Beam #1 crossed, beam #2 not crossed– no output.
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International Conference on Innovations in Engineering and Technology (IET 2011), August 8 th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O.A. AWOSOPE and M. ODEKUNLE
Beam #2 crossed, beam #1 not crossed –no output.
Beam #1 crossed first, then beam #2 – Test for system reconnection
a.
beams #1 reconnects before beam #2 – increment counter
b.
beams #1 reconnects before beam #2 – nothing happens.
4.
Beam #2 crossed first, then beam #1 – Test for system reconnection
a.
beams #1 reconnects before beam #2 – nothing happens
b.
beams #2 reconnects before beam #1 – decrement counter
This carefully produced design takes care of all scenarios such as partial entrance, leaning in, etc. In which
case there is an internal program that tests the state of the counter. A zero recorded on the counter indicates
that there is no occupancy and the lights will be OFF. If on the other hand, there’s occupancy, the counter
displays the number of people in the room and which lead to the activation of all light bulbs to be switched
ON.
2.
3.
X1
V4
U1
13
14
1
CRYSTAL
C8
2
3
4
5
6
7
1uF
R1
10k
C7
1uF
8
9
10
OSC1/CLKIN
OSC2/CLKOUT
MCLR/Vpp/THV
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/SS
RE0/AN5/RD
RE1/AN6/WR
RE2/AN7/CS
V1
RB0/INT
RB1
RB2
RB3/PGM
RB4
RB5
RB6/PGC
RB7/PGD
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
5V
33
34
35
36
37
38
39
40
R3
10k
5V
15
16
17
18
23
24
25
26
V3
5V
19
20
21
22
27
28
29
30
Q1
RL1
2N1711
12V
L1
12V
PIC16F877
R2
R4
10k
10k
V2
5V
Fig 5: Simulation of results using Proteus
Figure 5 shows the simulation of the circuit of the IES technology. The two push buttons connected to the
29th and the 30th pins of the PIC16F877 represent the signals from the beams. Depending on which push
buttons was pressed and based on the conditions earlier enumerated in the flow chart, there is an increase or
decrease in the counter value as displayed by the LCD unit. A zero displayed on this unit signifies that there
is no persons in the room and a signal is sent to the 28th pin (which is connected to the relay) thus switching
off the light bulbs in the room.
On the other hand, if the display indicates that there is room occupancy, a signal is sent through 28 th to the
relay and the light bulbs in the room are switched ON. The oscillator is a 4MHz crystal oscillator whose
duty is to determine the speed of operation of the microcontroller. The connection to the RB0/INT pin (pin
33) is a circuit that resets the counter on the LCD to zero.
Table 1 shows the power usage for the simulation of the IES technology by the Proteus VSM which depicts
the adequacy and functionability of the IES. It clear from this table that the Power usage is about 2W. Thus
9
International Conference on Innovations in Engineering and Technology (IET 2011), August 8 th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O.A. AWOSOPE and M. ODEKUNLE
it can be concluded that it is cost effective and (from the earlier presentation) it can be adjudged to be easy
to use.
Table 1: Power Usage Analysis
Components
Power
Usage
2 Beams (10V @ 32mA)
0.32W
PIC (5V @ 100mA)
0.50W
Relay (12V @ 100mA)
1.20W
Total Power
2.02W
5.0 CONCLUSION
The implementation of the IES technology has been shown to reduce energy consumption by turning the
light out when it is not needed and turning it on as soon as there is a need for it.
Currently, there are various types of light control devices available in the energy efficiency market, but none
has been able to combine optimum lighting efficiency with convenience of switching as does this new
design. Thus this work has presented the fact that the implementation of the IES technology has the
capability to save energy by eliminating false conditions which is common among other energy efficient
devices.
The IES technology could combine the following attributes namely, affordability, cost-effectiveness and
operation even during period of power failure.
This is then recommended to energy saving industries for mass production.
The implementation of the IES technology has been shown to reduce energy consumption by turning the
light out when it is not needed and turning it on as soon as there is a need for it.
Currently, there are various types of light control devices available in the energy efficiency market, but none
has been able to combine optimum lighting efficiency with convenience of switching as does this new
design. Thus this work has presented the fact that the implementation of the IES technology has the
capability to save energy by eliminating false conditions which is common among other energy efficient
devices.
The IES technology could combine the following attributes namely, affordability, cost-effectiveness and
operation even during period of power failure.
This is then recommended to energy saving industries for mass production.
REFERENCES
(1)
United States Department of Energy, Sun Feb 4, 2009 http://www.energy.gov
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International Conference on Innovations in Engineering and Technology (IET 2011), August 8 th – 10th,
2011. O. OBAJEMU, P. O. OLUSEYI, T. O. AKINBULIRE, C. O.A. AWOSOPE and M. ODEKUNLE
(2)
John-Felix Akinbami, Akinloye Lawal (2003). “Opportunities and Challenges to Electrical Energy
Conservation
and
CO2
Emissions
Reduction
in
Nigeria’s
Building
Sector”
www.urs2009.net/docs/papers/Akinbami.pdf
(3)
(4)
No Author (2001), Green Seal, Sun Aug 2, 2001 http://www.greenseal.org
No Author (2009), Conservation international Sun 02 Aug 2009 http://www.conservation.org
(5)
No Author, Energy Information Administration (EIA), Wed 12 Aug 2009, http://www.eia.doe.gov
(6)
B. Lowe, L. Johnson (2001). “Design Document for Automatic Light Control Device “ Mississippi
State University , Mississippi State, Mississippi.
(7)
No Author (2009), Occupant Sensors forum http://www.lightforum.com
(8)
R. L. Boylestad, L. Nashelsky (2006), “Electronic Devices and Circuit theory”, 9 th edition, Prentice
Hall of India, New Delhi 2006. 763-786
(9)
R.F. Hay(1941), “Characteristics of Low Voltage Fluorescent Lamps at High Frequencies.”.
Illuminating Engineering, Vol. 36, p.570.
(10)
J. Sanchez, M. P. Canton (2007). “Microcontroller Programming: The Microchip PIC”, CRC Press,
Florida, USA.
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