course material

1. QAC020X355A Designing And Developing Products For The Internet Of
Everything
Answer:
Title: Bluetooth Enabled Temperature, Humidity, and Gas Monitoring System
Introduction
Internet of things (IoT) refers to the interconnection of devices via the internet or other
communication networks. The devices collect, process, and share data among themselves
and with humans so that intelligent decisions aimed to promote efficiency and effectiveness
can be made. The success of IoT applications is facilitated by the emergence of technologies
such as low-power computing, cloud computing, mobile technologies, machine learning, and
big data analytics, which allow IoT devices to collect and share data with little to zero
human intervention (Sethi and Sarangi, 2017). In the modern world, IoT technology is
heavily being adopted to drive efficiency and new possibilities in the existing processes,
enable process changes in businesses, promote health care and environmental protection
services, improve the security and safety of physical assets, and create advanced efficiencies
in the manufacturing industry through the machine and product-quality monitoring
(Woungang, Dhurandher, and Visconti, 2021). This paper aims to develop an IoT system
that can monitor and regulate home temperature, humidity, and gas to promote the health
and wellbeing of home dwellers.
System Description
Temperature and humidity play a crucial role in the promotion of human health. High or
low-temperature values beyond the recommended thresholds are detrimental to people's
wellbeing and comfort. For example, exposure to extreme temperatures can result in a
cascade of ailments such as heat exhaustion, heatstroke, heat cramps, and hyperthermia. On
the other hand, exposure to extreme humidity conditions affects the body's ability to
regulate internal temperature and increases the risk of developing breathing difficulties or a
cold. Considering that human beings spend most of their time indoors and are significantly
affected, for better or for worse, by the quality of the environmental conditions inside the

2. buildings they spend their time, it is advisable to have a system that keeps the conditions
inside the buildings in check to ensure that they are always within the required threshold.
The system proposed in this paper is aimed to monitor and regulate the temperature and
humidity inside buildings and alert the users about extreme conditions so that human
intervention can be adopted if the need arises. In addition, the system detects the presence
of concentrated gases that may cause harm to human health. The system is achieved by
taking temperature, humidity, and gas readings in the building and displaying them on an
LCD screen. If the values are beyond the recommended limits (Humidity 40%-60%,
Temperature- , and presence of concentrated gas), the system will raise the alarm to alert
the user and start or stop fans, heaters, gas regulators and humidifiers in the building until
the required conditions are regained. Moreover, the measured temperature and humidity,
and gas presence will be transmitted to the user via Bluetooth to take additional actions or
store the data for future planning.
Functional System Requirements
The system's functional requirements are divided into four segments: inputs, processing,
output, and communication. The different segments are discussed below;
Inputs: The input segment comprises sensors used to collect temperature, humidity, and gas
data from the environment continuously. The temperature data is compiled using the
degrees Celsius scale, while the humidity is expressed as a percentage of the total moisture
in the atmosphere, while gas can either be present or absent based on sensor reading.
Processing: The processing section comprises a microcontroller. Serving as the system's
heart, the microcontroller is charged with analyzing and processing the acquired data and
making informed decisions based on the analysis result. For example, if the microcontroller
analyzed the data and notices that the temperature has fallen below the required threshold
(- ) it is required to put on the heaters and switch off the fan. On the other hand, if the
temperature is above the required threshold, the microcontroller will automatically switch
on the fan and switch off the fan. Likewise, the microcontroller will switch on or off the
room humidifiers when the humidity is out of the needed range. The microcontroller also
determines whether to raise the alarm if the conditions are too extreme or whether there is
a gas leakage.
Output: It consists of a display screen, fans, heaters, humidifiers, gas leakage indicator and
alarm bell. The display screen is used for real-time monitoring of the environmental
conditions, the fans run to reduce the room temperature if it's too high, the heater is turned
on to heat the room when the temperature is too low, the humidifier is used to regulate the
humidity of the room, the gas leakage indicator is used to show whether there is a gas
leakage, and the alarm bell is used to alert on critical conditions so that the necessary
human interventions can be adopted.

3. Communication: The communication segment conveys system information to clients in
remote locations. The system uses Bluetooth communication protocol and is expected to
effectively communicate data to the client up to 10m in an area surrounded by barriers and
up to 100m in open space.
Components Needed
The components required to develop the Bluetooth enabled temperature, humidity, and gas
monitoring system are discussed below;
Power Supplies
The power supplies used in the system will be used dependent on the devices. For example,
5V DC power supplies will be used for sensors and microcontrollers. On the other hand, 12V
DC power supplies will be used for fans and humidifiers, while a 240 V ac power supply will
be used for the heaters. All the devices used in the simulation software use a 5V dc power
supply for simulation purposes. The figure below is a schematic of the power supply used in
the real-life application of the system.
Figure 1: Power Supply of IoT Electronic Components
Temperature And Humidity Sensors
To save on cost and power requirements, the DHT11 sensor is selected since it serves as
both a temperature and a humidity sensor (Srinivas, Jabbar, and Neeraja, 2018). The sensor
is shown below;
Figure 2:Dht11 Temperature and Humidity Sensor
The Dht11 sensor consists of three pins, namely VCC, GND, and DOUT. The VCC (positive
terminal) is the input pin for the 5V power supply. The GND is the ground (negative power
terminal). The DOUT is the data pin to transmit the temperature and humidity data to the
microcontroller (Nussey, 2013). The sensor sends a signal to an active controller sensor,
and after activation, it responds with a 40-bit signal that is the temperature and humidity of
the surrounding.
Gas Sensor

4. The MQ-2 sensor is a robust sensor commonly used for detecting LPG, smoke, Alcohol,
propane, Hydrogen, Methane, and Carbon gases in the environment. It is made up of metal
oxide semiconductor since the gas sensing is based on the variation of the resistance of the
semiconductor when gas comes into contact with the material. The sensor uses simple
voltage divider network to detect the concentration of gases.
Figure 3:MQ2-Gas Sensor
The sensor operates at 5V DC and draws approximately 800mW. It detects gas
concentration anywhere between 200 to 10000ppm
Microcontroller
Arduino Uno R3 micro-controller has been selected as the best micro-controller for the
project because of its low cost, low power consumption, open-source hardware and
software, ease of programming, quick response, and compatibility of the IDE software with
any Operating System (Blum and Blum, 2013).
Figure 4: Arduino Microcontroller
The controller comprises analog and digital input and output pins to facilitate analog and
digital data transfer from and to other electronic devices (Ashley, 2021). Additionally, it
consists of communication pins that allow for wired and wireless communication.
Liquid Crystal Display
The liquid crystal display (LCD) displays the sensor data for continuous monitoring. The
16x2 liquid crystal display shown below has been used for simulation purposes.
Figure 5: Liquid Crystal Display
Buzzer
The buzzer will act as the alarm to alert the system user when the temperature and
humidity conditions are out of range. The recommended range for temperature is between
18 and 24 degrees Celsius. On the other hand, the recommended value for humidity is
between 40 and 60%. If the measured value goes below or beyond these ranges, the buzzer

5. will alert the system user of the critical conditions.
Heater, Fan, Gas Indicator And Humidifier
The heater is used to heat the room if temperatures fall below the recommended range. The
fan blows to regulate the room temperature if it is higher than the required range. Lastly,
the humidifier regulates the humidity of the room. For simulation purposes, 5V DC motors
have been used to symbolize the rotation of the fan and the humidifier. On the other hand, a
red LED bulb has been used to simulate the heater's and gas indicator’s working. The figure
below is a schematic of a typical heater, fan, and humidifier used in real-world IoT
applications.
Figure 6: Room Heater, Fan, and Humidifier
Bluetooth Modules
The HC-06 Bluetooth modules are used for communication purposes. The Bluetooth module
and its pinout are shown below. The modules were chosen because they consume low
power, are cheap, and have a high data transmission rate (up to 2.1Mb/s). They have higher
flexibility compared to other wireless protocols (Mackey and Spachos, 2018). The modules
are based on the Bluetooth 2.0 communication protocol and are designed to establish short-
range wireless communication between microcontrollers. They use the frequency hopping
spread spectrum technique (FHSS) to limit interference with other wireless devices within
the range and to have a full-duplex transmission (Karacheva, 2021). Moreover, data
transmission occurs in the frequency range from 2.402GHz to 2.480GHz.
Figure 7: HC-06 Bluetooth Module and Pin-Out
In this case, the temperature and humidity data are sent to a remote Bluetooth-enabled
device such as a phone or television for continuous monitoring. The virtual terminal acts as
the end user's Bluetooth-enabled device for simulation purposes.
System's Circuit Diagram
The circuit diagram of the Bluetooth enabled temperature, and humidity monitoring system
is shown below;

6. In the circuit diagram above, the dht11 sensor is connected to analog pin A0 of the
controller while the MQ-2 gas sensor is connected pin A1 of the controller. The humidifier is
connected to output digital pin 10, the fan to pin 9, the heater to pin 8, and the buzzer to pin
7. The connection of the LCD pinout is also shown above. The transmitter Bluetooth
module's TX pin is connected to the controller's RX, while the module's RX pin is connected
to the TX pin of the controller. The user's phone acts as the receiver device. However, since
the system above is based on simulation, the user side is not shown.
Description Of Programming Framework
Programming IDE
The Arduino Integrated Development Environment will be used for software programming
of the system. The IDE comprises a text editor for code writing, message area, text console, a
toolbar containing buttons for various roles, and many menus. The IDE links to the Arduino
hardware to upload programs and communicate with them. In this case, the IDE will
connect with the proteus simulation software. The Arduino IDE allows the program to be
written in the C language. The GUI of the IDE is shown below;
Figure 8: Arduino IDE
Simulation Software
Proteus simulation software will be used to simulate the working of the system. The Proteus
Design Suite is a proprietary software tool suite commonly used in electronic design. A
schematic of the simulation software is shown below;
Figure 9:Proteus Design Suite Software Schematic
Communication Protocol
This IoT system is based on Bluetooth communication protocol. The data collected using
sensors and analyzed using the microcontroller is sent to the client's remote device using
Bluetooth communication protocol for continuous monitoring. The HC-06 Bluetooth
modules are used to facilitate communication. The modules are based on Bluetooth 2.0
communication protocol and transmit data in the 2.402 GHz to 2.480GHz frequency range
(Mohamed, 2021). Additionally, the modules use the frequency hopping spread spectrum
technique (FHSS) to limit interference with other wireless devices within the range and to
have a full-duplex transmission. Since the project was accomplished through simulation, the
communication part has not been implemented but is included in the software code.

7. Implementation
System Code
The code uploaded on the Arduino microcontroller to facilitate the working of the IoT
system is shown below;
Software Testing When Temperature, Humidity, And Gas Are Within The Required Range
Figure 10: System Test 1
In this case, we notice that the value of temperature and humidity (57%) are within the
required threshold. Additionally, there is no gas leakage (Gas OK). Therefore, the heater,
fan, buzzer, gas leakage indicator and humidifier remain in the off state since no regulation
is required.
Software Testing When Temperature, Humidity, And Gas Are Outside The Required Range
Figure 11: System Test 2
In the above figure, the temperature is above the required maximum threshold of 24
degrees Celsius. Therefore, the FAN turns on (see the green LED is on), the buzzer turns on
to alert the user (see the red dot on the buzzer indicating power to buzzer), and the heater
remains off. On the other hand, the humidity level (57%) is within the required range.
Therefore, the humidifier remains in off status. Also, no gas is detected hence the has
leakage indicator remains off.
Figure 12: System Test 3
The temperature (20 degrees Celsius) is within the required threshold and no gas is
detected in the above figure. Therefore, the heater, fan, and gas leakage indicator remain off
(Fan, gas leakage indicator and Heater LED are off). However, the humidity (38%) is below
the required threshold. Therefore, the humidifier is turned on (humidifier Led is ON) to
regulate humidity. Additionally, the buzzer sounds to alert the user.

8. Figure 13: System Test 4
In the above figure, the temperature (13 degrees Celsius) and humidity (22%) are outside
the required threshold. Also, gas is detected. Since the temperature is below the minimum
required threshold, the heater is activated to heat the room. On the other hand, the
humidifier is activated to regulate humidity since the humidity is below the required
threshold, and the gas leakage detector is turned on due to gas leakage. The buzzer sounds
to alert the user of the critical conditions so that additional human interventions can be
undertaken based on necessity.
In this case, the system has been tested when there is a gas leakage (gas leakage sensor is
set to high) and humidity and temperature are within the required threshold. The gas
leakage indicator and the buzzer turn on to alert the user about the gas leakage.
Conclusion
The purpose of the paper was to develop an IoT system that can monitor and regulate the
temperature, humidity, and gas in homes and buildings. The system developed uses sensors,
microcontrollers, and display devices to monitor these environmental conditions
continuously. Additionally, the system conveys the data to the system user through
Bluetooth communication protocol. The data received by the client can be stored or used to
provide human intervention to the system when necessary. The other advantages of the
system developed are that it is less expensive than other systems in the market and
consumes much lower power than the presently available systems. Also, no user data is
required, and no human intervention is required routinely. Therefore, users should have no
concern over data privacy, confidentiality, or compromise on the system. Commercially, the
system can be used in high-rise buildings where environmental conditions are regulated
chiefly using artificial methods such as HVAC systems. Additionally, the system can be used
in residential buildings and offices to promote the dwellers' comfort.
References
Ashley, E., 2021. What is Arduino UNO? A Getting Started Guide.
Retrieved from https://www.rs-online.com/designspark/what-is-arduino-uno-a-getting-
started-guide
Blum, J, and Blum, J., 2013. Exploring arduino : Tools and techniques for engineering
wizardry. John Wiley & Sons, Incorporated, New York.

9. Karacheva, E. 2021. Bluetooth - How it works. Retrieved from https://ccm.net/contents/69-
bluetooth-how-it-works
Mackey, A., and Spachos, P. (2018). Energy consumption and proximity accuracy of BLE
beacons for Internet of things applications. 2018 Global Information Infrastructure and
Networking Symposium (GIIS). doi:10.1109/giis.2018.8635746
Mohamed, K. S. 2021. An introduction to Bluetooth. Bluetooth 5.0 Modem Design for IoT
Devices, 1-32. doi:10.1007/978-3-030-88626-4_1
Nussey, J., 2013. Arduino for Dummies. John Wiley & Sons, Incorporated, Somerset.
Sethi, P., and Sarangi, S. R. 2017. Internet of things: Architectures, protocols, and
applications. Journal of Electrical and Computer Engineering, 2017. Retrieved from
https://doi.org/10.1155/2017/9324035
Srinivas, K. Jabbar, M.A., and Neeraja, K.S. 2018. Sensors in IoE: A review. Retrieved from
https://www.researchgate.net/publication/328824424_Sensors_in_IoE_A_review
Woungang, I., Dhurandher, S. K., and Visconti, A. 2021. Internet of things design,
architectures, and protocols. Internet of Things, 14, 100267. doi:10.1016/j.iot.2020.100267