Bluetooth Enabled Temperature, Humidity, And Gas Monitoring System

Importance of Monitoring Temperature, Humidity, and Gas

Title: Bluetooth Enabled Temperature, Humidity, and Gas Monitoring System

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.

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 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.

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.

Functional Requirements of the System

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.

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.

The components required to develop the Bluetooth enabled temperature, humidity, and gas monitoring system are discussed below;

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

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.  

Components Required to Develop the System

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

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.

The liquid crystal display (LCD) displays the sensor data for continuous monitoring. The 16×2 liquid crystal display shown below has been used for simulation purposes.

 

Figure 5: Liquid Crystal Display

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 will alert the system user of the critical conditions.

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

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.

Power Supplies

The circuit diagram of the Bluetooth enabled temperature, and humidity monitoring system is shown below;

 

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.

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

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

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.

System Code 

The code uploaded on the Arduino microcontroller to facilitate the working of the IoT system is shown below;

 

 

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.

 

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.

DHT11 Sensor

 

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.

 

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.

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