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An IoT-based Automation System for Older Homes:
A Use Case for Lighting System
Naser Hossein Motlagh, Siavash H. Khajavi, Alireza Jaribion, and Jan Holmstr¨
om
Department of Industrial Engineering and Management
School of Science, Aalto University, Espoo, Finland
Emails: firstname.lastname@aalto.fi
Abstract—The integration of Internet of Things (IoT) plat-
forms in modern buildings has started to offer diverse services for
residents comfort and wellbeing. However, in addition to modern
buildings, where the use of IoT starts from the planning and
design stages, older homes (i.e. homes constructed more than a
decade ago) also have high potential to employ such platforms
and benefit from them. This paper presents the potential gained
benefits of such IoT implementations for older homes by propos-
ing an IoT-enabled control mechanism. Moreover, we illustrate
the impact of using IoT on reducing the energy consumption of
a home while ensuring comfort for the residents. To this end,
we develop a test-bed for an IoT platform where we use light
sensors to monitor the indoor ambient light. We then define a
control mechanism for the smart lighting system that is functional
on the IoT gateway and designed to control and adjust the
dimmable light sources. Through simulations, we compare the
conventional system power consumption (CSPC) of homes with
the smart system power consumption (SSPC) defined by our
control mechanism. The SSPC results demonstrate the potential
advantages of using IoT-enabled control systems in older homes.
In our case, the savings are in the form of reducing power
consumed for lighting while ensuring visual comfort for the
residents.
Index Terms—Internet of Things, Smart Homes, IoT Plat-
forms, Old Homes, Lighting System, Home Automation System.
I. INTRODUCTION
Buildings are major sources of energy consumption in var-
ious countries. The two main sources of energy consumption
in buildings are air conditioning (AC) systems and lighting
which respectively account for nearly 40% and 15% of total
electricity usage [1]. On a global scale, AC consumes an
estimated 1 trillion kilowatt-hours of electricity each year.
The use of AC may also increase by 10 times by 2050
in response to the rising temperature [2]. According to [3],
approximately 20% of electricity is consumed for lighting
worldwide. This amount is predicted to rise by 80% by 2030.
Thus, in buildings, AC and lighting systems are the two
main areas where improvements in energy efficiency must be
sought.
New technologies and control systems are needed to use
electricity more efficiently. Using the Internet of Things (IoT)
and IoT-based control systems can eminently reduce electricity
consumption and improve the energy efficiency of homes [4].
In fact, the use of IoT has already started in the building
industry and is growing at a rapid pace; this has mainly been
integrated with a modern building automation system (BAS).
Fig. 1. The required components for creating a smart home.
Thus, these buildings can be equipped with any suitable IoT
device [5]. In contrast, most older homes built more than a
decade ago are in shortage of a BAS to allow integration of
the IoT. However, these older homes have strong potential to
become smart with only small investments, since nowadays
most homes are equipped with the Internet through a wireless
communication technology such as a cellular system, e.g. LTE
4G, 5G, or Wi-Fi [6]. Actually, a smart home is a home
that uses the Internet-connected devices to enable remote
accessing, monitoring, controlling, and management of home
controllable appliances and systems. The examples of these
controllable appliances include TV sets, AC, and lighting
systems. Using this opportunity and implementing an IoT
platform, i.e. any appropriate gateway and sensor devices,
will provide diverse services for the users and a high level
of smartness for older homes. The concept of a smart home
is illustrated in Fig. 1.
In smart homes, electrical appliances and automation sys-
tems are connected to offer diverse services for the home users.
As shown in Fig. 1, these services provide comfortable, secure,
and healthy living environments for inhabitants, and enable
energy saving by reducing unnecessary energy consumption,
which also enhances the user’s comfort and offers greater
safety and security for the residents [7]. To enable a smart
home, IoT components can be integrated into controllable
home appliances. This allows the users to monitor and control
the functions of appliances, and provides a smart control and
report mechanism by the IoT platform itself. For example,
by equipping the home with an IoT gateway and appropriate
sensor devices, using the cloud and monitoring features of the
IoT platform, the indoor temperature can be controlled and set
to a desired level. In addition, using the sensors, outdoor light
received in indoor environments can be measured and utilized
as part of the required light for visual comfort. This certainly
affects the power requirements for the lighting system. In this
way, the energy required for the AC and the lighting system
can be minimized and, at the same time, thermal and visual
comforts can be offered for the residents.
To the best of the authors knowledge, there is limited
research on the idea of developing IoT platforms and offering
IoT services for older homes. Therefore, this paper aims to
illustrate the ease of converting older homes to smart ones
using IoT systems. To highlight the benefits of such a con-
version, this paper presents the use case of a lighting control
mechanism that is dependent on ambient light variations. To
this end, a test-bed is developed to show the use of IoT plat-
forms in homes. Then, the data collected from this test-bed is
used for the lighting control mechanism use case implemented
on the IoT gateway that is aimed at reducing lighting power
consumption. The rest of the paper is organized as follows.
Section II presents the concept of IoT platforms, general IoT
architecture, and a scenario to highlight the idea of activating
the IoT platforms for smart homes. Section III explains the
smart lighting system use case, the test-bed developed for
data collection, the lighting power control mechanism, and
the results produced using this mechanism. Finally, section IV
concludes the paper.
II. IOTPLATFORMS
An IoT platform is a multi-layer technology that enables
management and automation of IoT connected devices. In
general, it is an end-to-end software framework that facilitates
sending and receiving data from sensors, devices, and net-
works to provide actionable data for the users [8]. To further
discuss the characteristics of the IoT platforms, we explain
the general architecture of IoT and an IoT platform for smart
homes in II-A and II-B, respectively.
A. General IoT Architecture
IoT platforms are designed based on the needs of different
business scenarios and required industrial applications [9]. The
IoT architecture is open and generic and has the following
characteristics [10]: 1) standard interface and protocol (hard-
ware and software interfaces); 2) public and operating (fulfills
the needs of public IoT applications with open operating
capability); and 3) open, scalable, and flexible (easily can
extend its functionality and performance scales). Based on
Fig. 2. The layered architecture of IoT.
[11], we design a general IoT architecture that is open and
flexible in three layers: the sensing layer, network layer, and
application layer. This layered architecture model is shown in
Fig. 2.
1) Sensing layer: This layer connects sensors, actuators,
and other IoT devices to the network layer using an IoT
gateway [12]. The IoT gateway enables a connection to
be established with the desired number of different home
appliances and sensor devices. The gateway includes con-
trol modules, common interface modules, and communication
modules. Using the latter, the gateway allows communication
with different wireless (such as Wi-Fi, Bluetooth, ZigBee,
or cellular networks) equipped appliances. In addition, the
gateway offers limited data storage and data processing capa-
bilities. IoT devices (sensors) are the other building block of
the sensing layer. The selection of these devices and their types
can vary based on the intended use case. Due to the diversity
of available sensor devices in the market, it is necessary to
take into account the following considerations when selecting
them: i)sensors accuracy for data measurement, ii)sensors
battery life, if battery powered, iii)sensors cost, and iv)sensor
maintenance. In other words, repairing the faults should be as
easy as possible.
The actuators/controllers are the other components in the
sensing layer. An actuator is a physical device that is designed
to control a machine function. The actuator converts into
action the control message sent from the IoT platform [13].
When selecting it for the IoT platform in a specific application,
an actuator should i)match the characteristics of the IoT
platform, e.g. the communication technology of the platform;
ii)match the mechanical requirements of the controlled device
or machine; and iii)be suitable for the operating environment.
For example, a variety of smart thermostats exist for AC
which differ in size, price, and their equipped wireless access
technologies such as ZigBee, Z-Wave, or Wi-Fi [14]. Another
example is the light dimmers that are used to adjust the
light illuminance; these dimmers, for instance, can reduce the
energy consumption of the fluorescent lamps without affecting
their efficiency [15].
2) Network layer: The network layer offers common ca-
pabilities which can be utilized by different IoT use cases.
This layer comprises three components: control functions, data
storage and processing, and cloud services. Using the control
function, this layer enables communication networks. The data
storage and processing component allows the IoT platform to
continuously collect and store the streamed data through the
gateway. The stored data is used for processing, visualizations,
and analytics purposes. Finally, cloud services are the third
building block of the network layer. They offer a set of tools
to connect, process, store, and analyze the IoT data in the
cloud in real-time.
3) Application layer: The application layer consists of user
interfaces, IoT services, and the data visualizations. Using
the user interfaces, this layer provides information about the
IoT applications for the users. It also offers open application
programming interfaces that facilitate the development of IoT
applications. Furthermore, it enables end-to-end interactions
between the user and the IoT devices or sensors. For example,
through this interface, the user can turn a device on and
off or adjust values, e.g. indoor temperature, to the desired
level. Another component of this layer pertains to the visual
presentation of the real-time data received from the IoT
platform. This enables intelligent decisions to be made on
the performance of IoT devices and the IoT platform. This
feature allows the use of automated actions on the platform,
which improves the awareness and responsiveness of the
system. The other component in this layer is the various IoT
services offered by diverse IoT applications. These services
may include health-care, human comfort, security, and energy
savings and efficiency, as shown in Fig. 1.
4) Security Management: Security management plays an
important role in the IoT architecture by involving the security
issues of the architectures three layers [16]. In the sensing
layer, since the IoT devices are heterogeneous and each device
employs a different communication technology, security man-
agement should guarantee a balance between security features,
bandwidth, and power supply. In the network layer, since the
IoT devices may obtain personal information from the user,
and since IoT-enabled devices are capable of communicating
with one another, it is highly important to obtain a secure
communication network, in which users information should
not leak to other users. Finally, since there are numerous
IoT applications such as buildings and health monitoring,
the security management through the application layer should
guarantee a reliable IoT system; a single fault caused by the
IoT system may lead to tragic consequences.
B. IoT platform activation at smart homes: An Example
The AC and lighting systems are the two major sources
of energy consumption in older homes. Hence, to portray
the benefits of enabling an IoT platform for such buildings,
a scenario is constructed (Fig. 3). Let us assume that a
living room has AC and a lighting device, two highly power-
consuming systems, which are in use in a traditional way.
These devices can be controlled remotely in a smart way by
taking the following steps: equipping the AC with a suitable
Fig. 3. IoT enabled control system for smart home.
smart actuator or a smart controller; preparing a smart dimmer
for the lighting system; using an IoT gateway; employing
any sensor device that is capable of measuring parameters
like temperature, humidity, and light; and developing agile
software programs on the gateway. In this way, an IoT-
enabled appliance can be created in a households living room,
which transforms it into a smart room and results in reducing
unnecessary energy consumption while providing comfort for
the residents. In fact, by using a software application installed
on a mobile device, the amount of energy consumed by these
systems can be monitored and adjusted. The user can also be
informed about the status of the AC and lighting systems.
In addition, in most buildings, the direction and variation
of sunlight have a direct effect on indoor lighting and tem-
perature. However, by using smart curtains, the amount of
direct sunlight that enters a room can be controlled. Thus,
the amount of energy consumed by the AC system to cool the
room can be decreased, and thermal and visual comfort can be
increased for the residents. Furthermore, by employing smart
motion detectors in such a scenario, the lights can be switched
off when no user is in the room. This also enhances the
smartness of the home and efficiently reduces the amount of
power consumed by the AC and lighting systems. To illustrate
how the parameters measured by a sensor can affect the power
consumption of a household and how this can ensure comfort
for the residents, the next section presents a lighting use case
where the illumination is continuously adjusted by an IoT
platform.
III. SMART LIGHTING SYSTEM:A USE C AS E
To demonstrate the impact of employing IoT platforms in
older homes, we have developed a small-scale test-bed i)to
evaluate the amount of power required for the lighting system,
and ii)to ensure visual comfort for the users when considering
the outdoor light received from the window. In addition, this
test-bed shows the simplicity of developing IoT platforms to
convert older homes to smart ones. We describe this test-bed
in the following.
Fig. 4. Test-bed for indoor and outdoor light measurements.
A. The Test-bed
For the test-bed, we used an office room with a working
desk located under a fluorescent lamp with 40 watts opera-
tional power. To study the effect of the outdoor light received
in the indoor environment, we selected a single desk where the
light level was affected by outdoor light, and we placed a light
measuring sensor (in this case a Texas Instruments Sensortag),
on the desk. It is worth noting that the received outdoor light
varies in different rooms and in different locations in a room.
This variation is caused by adjacent buildings designs and
environmental factors, such as the location of the buildings,
the buildings surrounding environment, the height of the room
floor, and the number and sizes of the windows in each
room. In the test-bed, we measured the amount of outdoor
light received from the window while the lamp above the
desk was switched on, i.e. lighting. Fig. 4 shows the test-bed
environment. Meanwhile, we placed another Sensortag at the
window to measure the received outdoor light. In addition,
we used one Raspberry Pi 3 Model B+ as the IoT gateway
to connect to the Sensortags. To establish the communication
between the gateway and the sensors, we developed a Python
code in which we connected to the sensors and collected their
light readings measured in lux.
Furthermore, the Python code allowed us to connect to both of
the Sensortags at the same time and to receive real-time data at
the gateway. In the experiment, we stored the measurements of
the sensors from 8 : 00 to 20 : 00 at every minute continuously
without interruptions in separate .csv files on Raspberry Pi.
Fig. 5 illustrates the lux variations received from the outdoor
and indoor environments. The outdoor light variations were
caused by surrounding wall and window reflections around
the room, and the cloudy hours of the day. The light level
measured in the indoor environment was affected by a constant
lux value generated by the lighting system, i.e. the lamp above
the desk, and the outdoor light received from the window. To
show how to control the lighting power consumption based on
Fig. 5. Light variations received at outdoor and indoor environments.
the outdoor light variations received in the indoor environment,
we developed a power control mechanism in which we used
the stored data from the experiment; this is discussed in the
following.
B. Lighting power control mechanism
This sub-section demonstrates how to control indoor light-
ing power consumption in an intelligent way. To do this, the
input power of the light is dimmed based on the outdoor
light variations received in the indoor environment. Based on
[17], the relation between power consumption and lighting is
defined by:
P=A·Ev
η(1)
where, Pis lighting power (W),Evis the illuminance (lx),
Ais the area (m2), and ηis the luminous efficiency (lm/W ).
To control the power consumption of lighting system based
on real-time light intensity measurement by the indoor sensor,
we have developed the algorithm 1. In the algorithm, the user
sets the desired light intensity Ed
vthat is the visual comfort
level for the intended room, the lamps specific light intensity
Elamp
v, the lamps operational power Plamp, and the luminous
efficiency ηof the lamp. The user also sets the power required
for the dimming levels [18], i.e. P= [P1, P2,· · · , Pn]. The
algorithm works so that, when the light is switched on, the
lamp consumes the maximum operational power P[n]. Then,
the algorithm reads the existing light intensity in the indoor
environment Ein
v(received from the lamps and outdoor) and
calculates the difference λbetween Ein
vand Elamp
v.
Then, the algorithm checks that if the light in the indoor
environment is more than the desired amount, i.e. comfort
level, then it applies the Equation 1 and the difference in
luminous flux λto vary the input power of the lamp by
Pvar . The algorithm uses the variation power Pvar to dim and
control the lamps power consumption with the following steps.
First the algorithm takes Pvar and compares it with all of the
dimming power options P= [P1, P2,· · · , Pn]starting from
the first array. If Pvar becomes smaller or equal to the first
array, the algorithm selects P1as the input power of the lamp
that is the minimum dimming level. This condition ensures
the minimum lighting requirement and the visual comfort. If
Pvar is bigger than the ith power and smaller or equal to
the ith + 1 array, then it will select the ith + 1 power as the
input power of the lamp. This power is between the minimum
P1and maximum Pnpower options. This condition ensures
selecting the required and appropriate level of lighting to offer
visual comfort according the outdoor light variations. If Pvar
is bigger than the maximum power, then it will select the Pn
as the input power of the lamp. This condition guarantees the
visual comfort for the user. In conclusion, using this algorithm,
the light level of the lamp is controlled for near optimal power
consumption while ensuring the visual comfort for the users
of the room.
Algorithm 1 Indoor ambient lighting control based on inputs
from light sensor
1: Set (A, E d
v, Elamp
v, Plamp, η)
2: Set P = [P1, P2,· · · , Pn]
3: T urn lights on
4: while (T rue)do
5: Pinput =P[n]
6: Read (Ein
v)
7: Compute λ =Ein
v−Elamp
v
8: if (Ein
v> Ed
v)then
9: Compute Pv ar =A·(Elamp
v−|λ|)
η
10: else
11: λ= 0
12: Compute Pv ar =A·(Elamp
v−|λ|)
η
13: end if
14: for i=0 to length(P) - 1 do
15: if (Pvar 6P[0]) then
16: Pinput =P[0]
17: end if
18: if (P[i]< Pvar 6P[i+ 1]) then
19: Pinput =P[i+ 1]
20: end if
21: if (P[n]< Pvar )then
22: Pinput =P[n]
23: end if
24: end for
25: end while
C. Result and Analysis
To study the impact of the smart lighting system, we
compare the conventional way of using the lights with our
proposed smart IoT-based system presented in Algorithm 1.
In a conventional system, the lamp is constantly lighting,
regardless of any light fluctuations in the indoor environment.
In contrast, in the smart controlled system, the amount of light
generated by the lamp depends on indoor light variations. To
compare the amount of power consumption in the two systems,
using the data collected from our experiment explained in
III-A and using the algorithm defined in the previous sub-
section, we performed simulations in Python. To this end, we
Fig. 6. Power consumption based on ambient light intensity variations.
used the .csv file in which we stored the sensor readings of
the light from the indoor environment.
In simulations we have used a dimmer with seven dim-
ming steps of [40%,50%,60%,70%,80%,90%,100%] with
a dimmable lamp (equipped with electronic ballast which is
compatible with dimming) with maximum input power of
40 watts. Using this dimmable lamp there are seven opera-
tional input powers of [16,20,24,28,32,36,40](W). For the
luminous efficiency η, we assigned 75, for the light intensity
of the lamp Elamp
vwe used 500, and area size Ato be
equal to 1m2. In addition, we assigned Ed
vthe visual comfort
equal to 500 that is the required light level for a typical
office.In the simulations, we refer to the results as conventional
system power consumption (CSPC) and smart system power
consumption (SSPC).
Fig. 6 shows the power consumption of the two systems
in a varying ambient lighting. The observation is that the
CSPC remains constant regardless of light variations, while
the SSPC significantly decreases with the increase in the lux
values. Fig. 7 (a) illustrates the CSPC and SSPC at different
times of the day at every minute. The results show that the
SSPC is highly dynamic and depends on the received light
fluctuation in the indoor environment. The highest values
of lux were received between 10 : 00 and 18 : 00, and
the least power was consumed within this time interval. In
addition, Fig. 7 (b) demonstrates the average CSPC and SSPC
for each hour (W/h). This figure proves that employing
an intelligent control system developed on IoT platforms in
smart homes eminently decreases the energy required for the
lighting system. Thereby, the energy costs of these homes are
significantly decreased.
IV. CONCLUSIONS
Nowadays, AC and lighting systems are the two main
sources of electricity usage for which improvements must be
sought. Employing an IoT-based control system can potentially
reduce the electricity consumption and improve the energy
efficiency of households. While the use of IoT has started in
modern buildings, older homes that were constructed more
(a) Continuous power consumption in different times of the day.
(b) The average power consumption per hour.
Fig. 7. Performance of smart lighting compared to the conventional system.
than a decade ago also have high potential to host intelligent
IoT platforms. This is because new ubiquitous communication
technologies such as cellular networks and Wi-Fi can be
utilized with the IoT gateways and smart home appliances to
create smart homes.
In this paper, we proposed an IoT-enabled control mecha-
nism for lighting in older buildings. A use case was presented
to show how an IoT platform can reduce the power consump-
tion of a lighting system. To do this, we developed a small-
scale test-bed where we measured the light variations from
the indoor environment. The light was measured in an office
room with a sensor located on a work desk that received the
light generated from a lamp and the light from the outdoor
environment through a window. In the next step, a control
mechanism was defined which was functional on the gateway,
and we considered a dimmable lamp with seven dimming
levels. We used our collected data with the control mechanism
and compared the CSPC of homes with the SSPC defined by
our control mechanism.
The results obtained from the SSPC prove the advantages
gained from using the IoT enabled control systems at older
homes. It illustrated a significant decreases in the power con-
sumption for lighting. The results demonstrate that employing
IoT-based control system at older homes considerably reduces
the energy consumptions while offering services and ensuring
comforts for the residents.
ACK NOW LE DG EM EN T
This work is supported by DigiBuild project funded by
TEKES: Finnish funding agency for technology and innova-
tion [Project No.211612].
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