Friday, November 15, 2019

Implementation of Reliable and Cost Effective Smart Home

Implementation of Reliable and Cost Effective Smart Home Automation is the trend that will define the way we will live and work over the next decade. Current home automation systems have limitations in terms of wireless connectivity, speed, interference, bandwidth and cost of implementation. The proposed smart home system provides wireless control of appliances such as lights, fans, and alarms by using sensors and Bluetooth. Bluetooth provides higher transmission speed, greater bandwidth, and consumes less power than existing wireless protocols. Further, the cost of implementation is minimized with the use of sensors and Bluetooth. This design incorporates an ARM7 processor that continuously collects light intensity, temperature, and carbon-monoxide levels from sensors and compares it with threshold levels, to determine the control operation to be performed on home appliances. The ARM7 processor access appliances using Bluetooth. Further, this smart home system also allows individuals to directly control their appliances through a smartpho ne-based android application. This smart home system is implemented and tested under varying conditions to represent its efficiency. LIST OF ABBREVIATIONS ADC Analog to Digital Converter ARM Advanced RISC Machines BLE Bluetooth Low Energy CPSR Current Program Status Register DTE Data Terminal Equipment FEC Forward Error Correction FH-CDMA Frequency Hopping Code Division Multiple Access FIQ Fast Interrupt Request HVAC High Voltage Alternating Current LCD Liquid Crystal Display PPM RISC Parts Per Million Reduced Instruction Set Computer RSSI Received Signal Strength Indicator UART Universal Asynchronous Receiver/Transmitter UPB Universal Powerline Bus USB Universal Serial Bus CHAPTER 1 INTRODUCTION Home Automation Worlds Fair of 1934 in Chicago marked the birth of home automation. Initially, the industry could not make an enormous impact on society. The reason for the slow start was high price and complexity making it hard to install. However as smartphones and tablets came into existence, the implementation of this technology became much easier. The automation technology helps in achieving greater efficiency and provides higher security. Expectations from a Smart Home The major parameters to look for in the implementation of a smart home can be as follows: Compatibility of the protocol. The system should communicate with the major protocols in home automation like ZigBee, Z-Wave, and Bluetooth. Wireless access. The system should be capable of wireless connection such as Wi-Fi Connectivity thereby eliminating all physical complexities. Scope for expansion. The system should support a higher number of products. Scope for scheduling. The design of the system should be able to support scheduling of different tasks at home like turning off lights when nobody at home. Remote access. Having an Android support is imperative these days. If the system is compatible with a smartphone, it makes this process very smooth as almost every individual today has a smartphone. Emergency notification. The system should send messages indicating emergency or threat to the house. Smart Home Community Response Various studies have been conducted to find out if consumers are ready to take up smart home technology. A study from Coldwell Banker Real Estate and CNET carried out in June 2015, said that 28% of internet users in The United States have smart homes and 90% of them would recommend smart home technology. The report also suggests that 25% of Americans use smart home products which save them around 30 minutes a day on average which are equivalent to $1,000 per year. As per a survey, 75% of the smart homeowners believe that this technology brings peace of mind regarding security. CHAPTER 2 REVIEW OF LITERATURE Existing Protocols in Home Automation Industry The increase in the use of smart home systems leads to the development of different protocols. The protocols are selected based on the type of communication among various connected devices. Let us see the major protocols in home automation industry: X10 Technology X10 is the oldest home automation protocol developed in 1970. Initially, the technology was a powerline-based system which slowly went wireless. X10 technology uses the power lines in the home to allow communication between various appliances. X10 is reliable as it makes use of power lines. However, it is subject to interference from other devices in the circuit. It does not provide a speed communication between devices. It can only perform 16 commands sent one at a time. INSTEON Technology INSTEON was introduced in the year 2005. It was designed to bridge the gap between powerline systems and wireless protocols. INSTEON is compatible with X10 technology making it easy for those who have an existing X10 network. It supports automation novices which make setting up or adding devices easy for the non-technical users. INSTEON can support more than 65,000 commands. It is capable of transmitting commands with little interference. One need not have to enroll INSTEON into home automation network. INSTEON network can have more than 400 devices connected in a single installation. The dual-band mesh network can convert all powerline-operated devices into repeaters ZigBee Technology ZigBee is a wireless communication standard built by IEEE. It runs on 802.15.4 wireless communication standard. ZigBee is growing significantly in recent times. However, ZigBees full acceptance as a home automation protocol is still in question. The reason being its interoperability. In most cases, ZigBee devices have difficulty in communicating with devices from other manufacturers. Each device uses different methods to accomplish the same task which causes the difficulty in communication. Perhaps, for the same reason, manufacturers use ZigBee to limit third-party devices. Wi-Fi Technology Wi-Fi stands for Wireless Fidelity. Wi-Fi makes use of radio frequency transmission of data through the air. Speed in a Wi-Fi connection may vary from 1mbps to 2mbps. Wi-Fi works in the frequency band of 2.4 GHz. The range for Wi-Fi is 40-300 feet. Wi-Fi runs on an inbuilt technology known as frequency division multiplexing technology. However, the major drawback with Wi-Fi is the interference and bandwidth issues. With too many Wi-Fi compatible devices, each device must fight for bandwidth resulting in more time to respond thereby making it work slowly. Also, Wi-Fi consumes much power. CHAPTER 3 BLUETOOTH TECHNOLOGY In 1994, Ericsson Mobile Communications was the first to initiate research on the possibility of wireless links. Their aim was to develop a cost-effective solution to replace cables as a mode of communication between computers and peripherals. Ericsson along with Nokia, Intel, IBM, and Toshiba, formed a group known as Bluetooth Special Interest Group (SIG) with a common motive of developing the unique technology. The first Bluetooth technical specification released in 1999. Bluetooth Specification Bluetooth specification for Classic Bluetooth/Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR) is below in Table 1. TABLE 1. Specifications of Classic Bluetooth Technical Specification Classic Bluetooth Modulation Technique Frequency Hopping Modulation Scheme GFSK Modulation Index 0.35 Number of Channels 79 Channel Bandwidth 1 MHz Nominal Data Rate 1-3 Mbps Application Throughput 0.7 2.1 Mbps Nodes/Active Slaves 7 Security 56 128 bit Voice Capable Bluetooth Technology A Good Choice for Smart Home Bluetooth is a solution to some different issues which existed earlier, like: Speed.Bluetooth provides a transmission speed of 1 Mbps. It can handle up to three voice channels simultaneously. Power.Bluetooth technology has a special feature of limiting the transmitters power as per the demand. With the help of a Received Signal Strength Indicator (RSSI), a Bluetooth receiver can determine the transmission power required by the transmitter. Security.Bluetooth has three built-in features which aim at providing secure data or voice transmission Prevents access to transmitted data by providing proper authentication. Data is encrypted over-the-air (OTA) which eliminated eaves-droppings. Also, an appropriate key is required to decrypt such data It makes use of Frequency Hopped Spread Spectrum (FHSS) which further eliminates eavesdropping Reliability.Bluetooth Technology uses three techniques to ensure protocol reliability. They are Frequency Hopping Code Division Multiple Access (FH-CDMA), Error Correction and Received Signal Strength Indicator (RSSI). Therefore, with the help of these techniques, the performance degradation is minimized. CHAPTER 4 SYSTEM COMPONENTS Hardware Components TABLE 2. Components Required for the Design Power Supply 12V DC Battery Processor Advanced RISC Machine (ARM7) Serial Communication Universal Asynchronous Receiver and Transmitter (UART) Wireless Communication Bluetooth Module Sensors Light Dependent Resistor (LDR), Temperature Sensor (LM35), and Gas Sensor (MQ-2) Display Liquid Crystal Display (LCD)Smart Phone Display Loads/Appliances/Devices LED, Computer Fan, and Alarm/Buzzer Software Applications TABLE 3. Software Required for the Design MATLAB To capture the sensor outputs KEIL To write the code for the functioning of processor Flash Magic To deploy the code into the processor SYSTEM ARRANGEMENT Power Supply The prototype uses an AJC D1.3S battery with 12 Volt/1.3Ah configuration. Liquid Crystal Display The prototype uses an 1602A LCD module with following features 16 Character x 2 Line Single power supply of 5V Input data 4-bits or 8-bits interface 1/16Duty, 1/5Bias Relay The prototype uses NRP07-C12DS relay to control the loads. Rating 10A/28VDC Maximum Switching Voltage 30VDC Operate Time 8msec. Max Release Time 5msec. Max Bluetooth Module BT24 Bluetooth module is a low cost series from Amped RF Technology. Configuration Cortex-M3 microprocessor up to 72MHz UART, up to 921K baud 13 general purpose I/O 4 x 12-bit A/D inputs AmpedUP Bluetooth stack (SPP, IAP, A2DP) Support Apple IOS/MFI Bluetooth devices. BT24 Features Bluetooth v3.0 Range up to 60m LOS 400 Kbps data through-put 128-bit encryption security. Advanced RISC Machine (ARM) Processor In 1985, Acorn computers developed the first prototype of ARM in England. ARM stands for Advanced RISC Machine. Currently, ARM is designed and marketed by ARM Holdings. As the name suggests, ARM uses RISC (Reduced Instruction Set Computer) architecture. The design, instruction set and decode mechanism of the RISC is much simpler than Complex Instruction Set Computer (CISC) design. ARM Features ARM7 has the following features: 32-bit RISC processor Low power consumption: 0.6mA/MHz at 3V fabricated Fast interrupt response for real-time applications Fully static operation ideal for power sensitive applications High-performance RISC: 17 MIPS sustained at 25 MHz at 3V In-System Programming/In-Application Programming (ISP/IAP) via on-chip boot- loader software. Single flash sector or full chip erase in 400 ms and programming of 256 bytes in 1ms. Universal Asynchronous Receiver and Transmitter (UART) UART is a chip designed to control all serial devices connected to a processor. The name asynchronous means that UART does not need a predefined clock for synchronization. UART comes with an RS232 Data Terminal Equipment (DTE) which helps to communicate with serial devices. It has a Start bit, seven data bits, a parity bit and a stop bit. UART provides a full duplex transmission which means that data transfer is possible in two ways, simultaneously. Therefore, both the ends have to come to an agreement with the parameters like word length, a parity bit, and some stop bits. Features UART has the following features, Burst rates up to 6 M-bits/second High level of transmission and reception of data UART converts the received bytes into single serial bit stream for transmission Provides buffering of data to maintain the coordination of serial devices with the computer Parity, overrun and framing error detection. Light Dependent Resistor (LDR) Sensor An LDR has a resistance which changes as per the amount of light falling upon it. It is often used to detect the presence of light in a circuit. An LDR has a high resistance of about 1000000 ohms. However, the resistance falls drastically once the bright light falls on it. Characteristics TABLE 4. LDR Characteristics Parameter Conditions Min Type Max Unit Cell Resistance 1000 LUX10 LUX 4009 OhmK Ohm Dark Resistance 1 M Ohm Dark Capacitance 3.5 pF Rise Time 1000 LUX10 LUX 2.818 msms Fall Time 1000 LUX10 LUX 48120 msms Voltage AC/DC Peak 320 V max Current 75 mA max Power Dissipation 100 mW max Operating Temperature -60 +75 Deg. C Temperature Sensor LM35 is a national semiconductor precision temperature sensor. It is a temperature sensitive voltage source. For every 1oC rise in temperature, the voltage increases by 10mV. In other words, the output voltage is linearly proportional to the temperature. Specification Linear +10-mV/oC scale factor Rated for full -55 oC to 150 oC range Suitable for remote applications Operates from 4 V to 30 V Low self-heating, 0.08 oC in still air 0.5 oC ensured accuracy (at 25 oC). Smoke Sensor MQ-2 gas sensor consists of a sensitive material called SnO2. SnO2 has lower conductivity which helps in the working of MQ-2 in clean air. Characteristics High sensitivity to LPG, Propane and Hydrogen Sensitivity to Combustible gas in wide range Long Life and Low Cost Specifications TABLE 5. Specifications of Gas Sensor Concentration 300 10000ppm Loop Voltage 5 Slope

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