Energy Efficient Outdoor Light Monitoring and Control Architecture Using Embedded System

Abstract

In this letter, we propose an energy efficient ZigBee-based outdoor light monitoring and control system that can monitor and handle outdoor lights more efficiently as compared to the conventional systems. The proposed system uses the ZigBee-based wireless devices which allow more efficient lamps management. The designed system uses sensors to control and guarantee the optimal system parameters. To realize effectiveness of the proposed system, the prototype has been installed inside the University, where the experimental results proved that the proposed system saves around 70.8% energy for the outdoor street environment because of using sensors, LED lamps, and ZigBee based communication network.

Full text

Abstract—In this letter, we propose an energy efficient
ZigBee-based outdoor light monitoring and control system that
can monitor and handle outdoor lights more efficiently as
compared to the conventional systems. The proposed system uses
the ZigBee-based wireless devices which allow more efficient
lamps management. The designed system uses sensors to control
and guarantee the optimal system parameters. To realize
effectiveness of the proposed system, the prototype has been
installed inside the University, where the experimental results
proved that the proposed system saves around 70.8% energy for
the outdoor street environment because of using sensors, LED
lamps, and ZigBee based communication network.
Index Terms— embedded system, energy efficiency, lightning
control system, LED lamps, ZigBee.
I. INTRODUCTION
nergy efficiency is one of the key factor while designing
indoor or outdoor lighting systems. The street lights
consumes almost 30-40% of the entire city power consumption.
Thus, control system able to efficiently manage the lighting is
absolutely advisable. For this aim, because of its design based
on the old lighting standards and inefficient instruments and
devices, the traditional lighting systems are not suitable
resulting in energy losses, frequent replacement of devices.
Moreover these traditional systems suffer from the lack of
pervasive and effective communications, monitoring,
automation, and fault diagnostics problems.
To address these challenges, many technologies has been
utilized in the literature to save energy such as: the utilization of
the light emitting diode (LED) instead of metal halide (MH)
lamps [1]. But the systems based on these technologies need
further improvement to increase the energy efficiency.
To further reduce the energy consumptions and to simplify
the wiring structure, numerous lighting control systems have
been proposed to solve that problem such as: occupancy
sensing approach [2], light level tuning [3], and power line
communication (PLC). Despite of reducing the wiring structure
in PLC based designs presented in [4], occasional drops may
occur in PLC networks operating on low voltage power lines.
This work was supported by the Ubiquitous Sensor Networks Research
Center (USNRC) as one of the Gyeonggi Regional Research Centers (GRRC)
chartered by Gyeonggi Provincial Government, South Korea.
Zeeshan Kaleem is with the Electronics Engineering Department, Inha
University, Korea (e-mail: zeeshankaleem@gmail.com).
Tae Min Yoon and Chankil Lee, are with the Electronics Department
Hanyang University, Digital Communication Laboratory, Hanyang University,
Korea (e-mails: wide1997@nate.com, cklee@hanyang.ac.kr).
These drops are caused by noise and attenuation, and can last
from a few minutes to few tens of minutes. Due to carrier signal
attenuation, there may be high latency or communication
failure in PLC based design. On the contrary, deploying
communication infrastructure based on wireless sensor
networks (WSNs), such as low power ZigBee, eliminates
wiring overheads and save lots of energy.
To implement wireless control system of lights, several
comparable architectures have been applied for outdoor
lighting [5]-[7]. The author in [5] design the intelligent lighting
system by considering the system cost as the main factor beside
the energy saving. In [5], the author tries to reduce the number
of sensors on each lighting nodes, but this reduction will result
in less accuracy of the system due to more packet loss and
hence will result in performance degradation. Furthermore, the
authors in [6] and [7] designed the energy efficient lighting
control system by utilizing the WIMAX and GPRS as a
backbone technologies, respectively, to communicate with the
control center. One of the drawback of utilizing WIMAX and
GPRS is the utilization of licensed spectrum, which will result
in interference with the existing WIMAX and GPRS users.
Hence, the lighting system will also require efficient
interference avoiding algorithms to cope with interference, but
this is not suitable for the lighting systems. These systems also
have no capability to change the light intensity according to the
users’ requirement because they statically control the energy
consumption and do not consider the user requirements in the
sense of light intensity and the user’s presence while dimming
or turning off the lamps. In [8], the proposed ZigBee based
lighting control system work was not being tested completely
for different seasons and users moving conditions, and hence it
was not completely verified and tested for different conditions.
In order to fill this research hole, we design the energy
efficient ZigBee-based outdoor light monitoring and control
system (ZB-OLC) that considers the users’ requirement and
system energy consumption. The proposed ZB-OLC system
also implemented the standard mesh routing algorithm which
results in better network performance as compared to the
conventional systems. The proposed ZB-OLC system also
fulfills the user satisfaction by using occupancy and
illumination sensors, and gives the gate to design the advance
metering infrastructure (AMI). Hence, the designed ZB-OLC
system dynamically controls the energy level of outdoor users
while guaranteeing their predefined minimum satisfaction
level.
Energy Efficient Outdoor Light Monitoring and
Control Architecture Using Embedded System
Zeeshan Kaleem, Tae Min Yoon, and Chankil Lee
E
Accepted in IEEE Embedded System Letters

II. PROPOSED SMART ENERGY EFFICIENT LIGHTING SYSTEM
In this paper, we design ZigBee-based energy efficient
outdoor lighting control systems as shown in Fig. 1. For
outdoor lighting environment, we select the Hanyang
University Lake as a test field and installed the LED lamps
accompanied by ZigBee module, light sensors, occupancy
sensors, and temperature sensors. The lamps continuously
monitor the intensity of the sunlight by using the sensors
connected to it, and based on that intensity ATmega128
microcontroller unit (MCU) takes the decision to dim and turn
the lamps on or off. Information is transferred hop by hop from
one lamp to another, where each lamp has a unique address in
the system. Each lamp can only send the information to the
nearest one until the information reaches the coordinator.
A. Lamp Monitoring System
The lamp monitoring system installed in each lamp consists
of several modules: the light sensor, temperature sensor, and
occupancy sensor, power metering IC, MCU, ballast actuator,
and ZigBee radio communication module (RCM) as shown in
Fig. 2 (a). Sensors are attached with ZigBee RCM nodes to
continuously monitor the situation of the lamps. The sensors
are used to observe the main parameters such as lamp-housing
temperature, power consumption, and illumination condition of
the place. These devices work together and transfer all of the
information to MCU which processes the data and
automatically sets the appropriate course of action. The detailed
discussions related to the main components involved in the
lamp monitoring system is given in subsections.
1) ATmega128 Microcontroller Unit
The ATmega128 MCU is installed at each lamp and controls
the operation of the whole node. Light and temperature sensors
gathered the information and send it to the MCU for
appropriate action according to the situation. After the initial
setting, the system is controlled by light and occupancy sensors
which activates the MCU if the sunlight is lower than the
threshold or some person passed through the street or building.
The passive infrared motion detector sensor (i.e., se-10 PIR) as
shown in Fig. 2 (b) is being installed in each lamp which is used
to check the presence of passengers or cars passing in the
streets.
MCU manages information flow among sensors and ballast
actuator, and is also responsible for generating pulse width
modulation (PWM) signal for dimming the LED lamps. The
MCU interface block diagram is shown in Fig. 2 (b), which
shows the interfaces used by MCU to communicate with other
connected devices.
2) Light Sensors
Light sensors, BH1710FVC, are connected to the MCU
through I2C interface which observe light status in Lux. A light
sensor measures the brightness of the sunlight and adjusts the
light intensity of the lamp to keep the light intensity up to 200
lux. The purpose of this measurement is to ensure a minimum
level of illumination of the outdoor lights, as defined by
regulations [9]. Based on the sun-light intensity, the MCU
drives the lamp to maintain a constant level of illumination, that
is, minimum horizontal and vertical illuminance of 15 lux and
50 lux, respectively [10]. Thus, the lamp will be turned on when
the sun-light will fall below this illuminance level. This action
is obviously not required during daylight time.
3) ADE7753 Energy Metering IC
The energy metering IC ADE7753 is used to measure the
status of a lamp. The highly accurate electrical power
measurement IC is connected to the MCU via serial peripheral
interface (SPI). It connects directly to the current and voltage
sensors and needs only single 5 V power supply. The current
sensor measures the current flow towards the lamp, which
allows to monitor the default in a lamp. The fault in a lamp will
be detected if the current level fell below the threshold of 0.3 A.
4) Blast Actuator
The blast actuator is an add-on actuation module interfacing
the dimmable ballast. The actuation module receives the
wireless actuation command and translates them into the ballast
control signals to dim the lights. In the proposed system, a
ballast actuator can control up to maximum of four LED
modules (units) each of 35 W rated powers with a required
current of around 0.5 A for each module. LED modules are
capable of multi-level dimming control, i.e., from 0 to 255 of
(a)
(b)
Fig. 2. Proposed LED smart lamp (a) Monitoring system block diagram
(b) Microcontroller unit interface block diagram.
Fig. 1. Proposed energy efficient architecture for outdoor lighting
environment.

lamps using monitoring and control software.
5) Gateway Node
A gateway node is used to serve as a bridge between two
networks, i.e., ZigBee and internet to perform the protocol
conversion. Each lamp controller communicates with the data
center via a gateway. Gateway provides the backhaul link to the
data center and ZigBee module to connect with the street light
control terminal. In the proposed system, attributes of LED
lamps are remotely observed and controlled through ZigBee
gateway which connects to the internet via Ethernet protocols.
B. ZigBee Radio Communication Module and Network
1) ZigBee Radio Communication Module
ZigBee RCM uses the universal synchronous and
asynchronous serial receiver and transmitter (USART)
interface to connect with MCU. ZigBee is the low power
wireless network standard based on IEEE 802.15.4 and defined
by ZigBee Alliance. It focuses on low power, low cost, high
reliability, and self-healing characteristics. It is the main part of
the proposed designed system and consists of two main parts,
i.e., Ember’s EM250 radio chip [11] and antenna for
communication purpose as shown in Fig. 3. Ember’s EM250
ZigBee stack is a single-chip solution that integrates a 2.4 GHz
IEEE 802.15.4-compliant transceiver. This chip can be
programmed by using ISP pins to program the flash memory of
the chip.
2) ZigBee Network
The ZigBee network layer has three kinds of topologies
named as star, tree, and mesh topologies. The proposed system
is based on the mesh topology, because it has self-healing
infrastructure and has extra path which can be helpful to reach
the coordinator if one fails to work. Due to high radio
sensitivity of the ZigBee receiver, it has less than 1% of packet
loss rate. Furthermore, it has good operational range for the
application reaching hundreds of meters outdoors.
Furthermore, the lamps installed in the deployment area using
ZigBee network has the clear line-of-sight (LOS) situation with
no trees or other objects obstructing the communication.
III. TEST CASE IMPLEMENTATION AND DISCUSSIONS
The system is designed to modernize the traditional wired
outdoor lighting system with the energy efficient ZigBee-based
wireless system. The proposed prototype has been tested under
outdoor scenarios to verify its validity, functionality, and
performance in the real-life conditions. The LED unit that
replaced the conventional lamp is shown in Fig. 3. To reduce
uneasiness of handling and difficulty of maintenance in
operating street lighting control system, we design smart LED
street light control system by using ZigBee as a wireless
communication protocol to save energy.
The proposed energy efficient system consists of 22 units of
70 W LED lamps and 16 units of LED 140 W lamps that
replaced the conventional MH street light lamps of 150 W and
250 W lamps, respectively, in the Hanyang University, Korea.
The spacing between the lamps are approximately 40 m. The
short comparison has been done between the LED and the MH
lamps in Table I. From, the Table I, we can see that although
the MH lamps has more efficiency as compared to LED lamps,
but this efficiency is compensated by the losses occurred in MH
lamps, such as, trapped light, unfavorable operating
temperature, high power requirement, and inefficient ballasts.
Moreover, LED lamps the energy consumption is less that MH
lamps and also have long life span which in turn effectively
reduces the cost of LED lamps. Thus, LED lamps are more
suitable than the conventional MH lamps.
Each street lights have been assigned identity to identify it
remotely from the central control station. The control center is
used to check the real time status of the lights and helps in
detecting the faults.
To accurately analyze and compare the performance of the
proposed ZB-OLC energy efficient street light system and the
conventional lighting control system, the system has been
tested for two extreme months of summer and winter, i.e.,
during the months of June, July, December, and January.
Equation (1) is utilized to calculate the energy consumption per
month of the installed lamps units.
( ) / / / / 1000,
consume
E KWH month P TL h day days month=×× ×
(1)
where P is the power in watts, TL is the No. of installed lamps,
and h/day are the operating hours per day. The results of these
tests are summarized in Table II for the above mentioned
months. The results clearly indicate that for the conventional
system, i.e., the system without having any smart options of
energy saving like diming of lights and usage of occupancy
sensor, has to turn on for 12 h/day (i.e., from 7:00 PM to 7:00
AM) in the worst case in the month of December. Thus the
energy consumption in this case will be around 2628
KWH/month. On the other side, by using the proposed energy
efficient system this energy consumption is reduced
dramatically from 2628 KWH to 765 KWH, i.e., around 70.8%
TABLE
I
COMPARISON OF LED LAMPS WITH METAL HALIDE LAMPS
Properties
LED Lamp
Metal Halide Lamp
Efficiency [lm/W]
55
80
Lifetime
[×1000 hours] 10-50 6
Losses Very Low
Trapped light,
unfavorable operating
temperature, inefficient
ballasts
Power Rating
[Lumen Produced] 70 W [3850 lm] 150 W [12000 lm]
Fig. 3. LED unit with front and back view.

TABLE
II
ENERGY CONSUMPTION PER MONTH (CONVENTIONAL VS. PROPOSED SYSTEM)
Duration
Convent ional System
Propose d Energy Efficient System
Lamps
Unit s
Installed
Rating of Lamp
units (W)
(Metal Halide
Lamps)
Operating
hours/day
Energy Consumption / month
(/day*30) (KWH)
[From Eq. (1)]
Lamps Units
Installed
Rating of Lamp
units (W)
(LED Lamps)
Operating
hours/day
(Time Average)
Energy Consumption / month
(/day*30) (KWH)
[From Eq. (1)]
June
22
150
9
(a) 29.7
Total (a+b):-
65.7*30=1971
22
70
5
(a) 7.7
Tot al
(a+b):-18.9*30
=567
16 250 9 (b) 36 16 140 5 (b) 11.2
July
22
150
9.5
(a) 31.35
Total (a+b):-
69.35*30=2081
22
70
5.5
(a) 8.47
Tot al
(a+b):-20.8*30
=624
16 250 9.5 (b) 38 16 140 5.5 (b) 12.32
December
22
150
12
(a) 39.6
Total (a+b):-
87.6*30=2628
22
70
7
(a) 9.8
Tot al
(a+b):-25.5*30
=765
16 250 12 (b) 48 16 140 7 (b) 15.68
January
22
150
11
(a) 36.3
Total (a+b):-
80.3*30=2409
22
70
6.5
(a) 10
Tot al
(a+b):-24.6*30
=737
16 250 11 (b) 44 16 140 6.5 (b) 14.6
of the energy is saved per month. This energy reduction is due
to the usage of LED lamps instead of conventional MH lamps,
diming feature of LED lamps, and by using the occupancy
sensors. These features reduce the average operating time of the
proposed system to 7 h/day in low traffic area whereas to 8
h/day in case of busy streets. The bar charts are plotted for the
two extreme months of the year for summer and winter, i.e.,
June, July, December, and January, respectively as shown in
Fig. 4. The results clearly indicate that the energy consumption
of the proposed ZB-OLC system decreases noticeably
compared with the conventional systems.
Furthermore, the energy consumption reaches its peak value
in the month of December for both the systems. Moreover, the
energy consumption for the proposed ZB-OLC system
decreases more in sunny months and reaches the bottom value
in June for both the systems. In case of the proposed system,
due to its smart weather adapting capability its operating h/day
reduces more, and hence results in more energy reductions as
compared to the conventional system. Thus, the proposed
energy efficient system is very helpful for the operators and as
well as for the customers due to its features of smart weather
adapting capability. Consequently, the sole price to consider is
that of the installation and implementation of the system with
saving thanks to lower maintenance and energy costs.
IV. CONCLUSION
The centralized and smartly monitoring of outdoor lights is the
cost effective and energy efficient way of saving precious
energy. In this paper, the novel ZB-OLC system is proposed,
which can smartly adjust the intensity of the LED lights
according to the sunlight conditions. In addition, the designed
system can remotely monitor the lights status, power
consumptions, and the cost of the individual lights as well as of
the total system. By using the proposed system, the faults in the
lights can be easily detected remotely and can be recovered
with less time, which will save the labor cost for frequently
monitoring the system. It can adopt to the changing conditions
in a more proactively and timel y manner. Furthermore, the
proposed system is suitable for outdoor lighting in urban and
rural areas with slight modifications where the traffic can be
low or high during different time intervals. The designed
system is flexible, extendable, and fully adaptable to the user
needs.
REFERENCES
[1] W. Yue, S. Changhong, Z. Xianghong, and Y. Wei, "Design of new
intelligent street light control system," in Proc. IEEE International
Conference on Control Automation, 2010, pp. 1423–1427.
[2] C. Ozcelebi, and J. Lukkien, "Exploring user-centered intelligent road
lighting design: a road map and future research directions," IEEE Trans.
Consum. Electron, vol. 57, pp. 788-793, May 2011.
[3] C. Chun, C. Hung, L. Kun, C. Kuan, and Y. Chun, "A digitally wireless
dimmable lighting system for two-area fluorescent lamps," in Proc. IEEE
Region 10 Conference, 2010, pp. 2173-2178.
[4] L. Chushan, W. Jiande, and H. Xiangning, "Realization of a general LED
lighting system based on a novel Power Line Communication
technology," in Proc. IEEE Applied Power Electronics Conference and
Exposition, 2010, pp. 2300-2304.
[5] P. Elejoste et al., "An Easy to Deploy Street Light Control System Based
on Wireless Communication and LED Technology," Sensors (Basel), vol.
13, no. 5, pp. 6492–6523, May 2013.
[6] F. Leccese, M. Cagnett, and D. Trinca, " A Smart City Application: A
Fully Controlled Street Lighting Isle Based on Raspberry-Pi Card, a
ZigBee Sensor Network and WiMAX," Sensors (Basel), vol. 14, no. 12,
pp. 24408–244424, Dec. 2014.
[7] L. Yongsheng, L. Peijie, and C. Shuying, “Remote Monitoring and
Control System of Solar Street Lamps Based on ZigBee Wireless Sensor
Network and GPRS,” Electronics and Signal Processing Lecture Notes in
Electrical Engineering, vol. 97, Springer, 2011, pp. 959-967.
[8] A. Siddiqui, A. W. Ahmad, H. K. Yang and C. Lee, “ZigBee Based
Energy Efficient Outdoor Lighting Control System,” in Proc. ICACT,
2012, pp. 916-919.
[9] European Committee for Standardization, Road lightning Performance
Requirements EN 13201-x, 2004.
[10] Z. Kaleem, I. Ahmad, and C. Lee, “Smart and Energy Efficient LED
Street Light Control System using ZigBee Network,” in Proc. FIT, 2014,
pp. 361-365.
[11] Ember Corporation, "EM250 single-chip ZigBee/802.15.4 solution,"
120-0082-000V datasheet, May 2013.
Fig. 4. Energy consumption comparison using conventional and
proposed energy efficient system.
June July December January
0
500
1000
1500
2000
2500
3000
Months
Energy [KWH]
Conventional Syst em
Proposed Energy Efficient Syst em