Lecture Note
University
University of CambridgeCourse
0455 IGCSE | EconomicsPages
9
Academic year
2023
Azizi Azache
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0
1. INTRODUCTION 1.1. Summary of Document Contents In this document, the concepts and ideas of the final project entitled "IoT-based automatic clothesline collection device" are described. Chapter 1 contains a summary of the contents of the document, purpose of writing, references, and a list of abbreviations. Chapter 2 contains the background and analysis of the needs of this project. In chapter 3, a list of components needed, simulation results are included, so that they can be used so that the objectives of this tool project can be achieved. 1.2 Purpose of Writing, Application, and Document Functions The purpose of writing this document is as follows: 1. Describes the design of an IoT-based automatic clothesline collection tool 2. The basis for the design and development of design-oriented tools is derived from specifications and can be implemented for household needs and the laundry business. 3. As a reference for carrying out system implementation to ensure and evaluate the system against predetermined specifications. This document is addressed to the supervisor of the final task of the Electrical Engineering Study Program, Brawijaya University as material for final project assessment.
2. DESIGN 2.1. Definitions, Functions, and Specifications 2.1.1 Definition and Function Drying clothes is a household activity. Washed clothes should be hung in the sun to dry. The drying process is usually in the sun. By letting the clothes dry in the sun, the clothes will become dry. The water that is on the clothes will move or evaporate due to sunlight. In addition, water also moves because of the wind. Almost every morning housewives do work, among the routine jobs they do are washing and drying clothes. Clothes that have been washed need to be dried in the sun to dry so they are comfortable to wear. The activity of drying clothes is usually done in the morning, when the sun is shining brightly. With sunlight the water content in wet clothes will evaporate. A few hours later the clothes became dry. Drying clothes should not be too long. When it is dry, the clothes must be removed immediately. If clothes are left in the drying area, then the dust carried by the wind will stick to the clothes. As a result, clothes will contain bacteria and germs. The many problems that arise in this drying activity will have a negative impact on several forms of business, especially for laundry service business actors. One of the problems that arise in some laundry businesses is in terms of lifting the clothesline when it rains. As we know the weather in Indonesia is often erratic, sometimes when the weather is hot, it suddenly rains heavily. Or sometimes when the weather is bad, suddenly it's bright. Under these conditions, it is necessary to have an automatic clothesline that can at least help housewives and the work of laundry employees. One way for clothes to be dried is to make optimal use of the available sunlight and can also save time and energy. This IoT-based automatic clothesline collector tool works by pulling the clothesline when the water drop sensor detects rain and will activate the motor with the help of an arduino that will drive a DC motor which will pull 2
the clothesline and collect it and when the power goes out this tool will still be able to work with the relay in the circuit. switching power source 12 V 7Ah battery 2.1.2 Summary of Specifications 2.1.2.1 User Interaction with the Tool The definition of interaction with the user in this discussion is everything that needs to be done by the user on the system so that this system can run according to its function. Several types of user interaction required in this system are as follows. 1. Initial Configuration, namely the user needs to attach the battery to the detection subsystem and connect to the application available on the smartphone, then ensure the detection subsystem with the application is properly connected. 2. Detection Subsystem Configuration, namely the user turns on the subsystem and checks the availability of power in the battery through the LED indicators on the subsystem. Then the user wears the detection subsystem on the wrist. 3. Main Station Subsystem Configuration, i.e. users need to download the available applications. Then the user configures the main station subsystem by opening the user interface Whichfound on mainstation application and connect the device (smartphone) to the internet. The user interface will tell whether the subsystem is connected to the database or not. 2.1.2.2 Capability and Functionality The following is a system specification based on the capabilities 3
and functionality of the system required. 1. This system consists of 2 separate subsystems which consist of 2 rectifier circuit subsystems and a DC filter to get the desired voltage output to be forwarded to the driving motor. 2. Flexibility, this tool helps and facilitates sunbathing activities because users can control and monitor the clothesline remotely. 3. This system has easy operation, with the help of the Internet of Things (IoT) users can find out the condition of the clothesline directly. 4. As a power source, this tool is equipped with a liquid battery that can supply power to the tool when a blackout occurs. 2.2. Tool Design Overview 2.2.1 Definition of Tools and tool subsystems This system consists of two main subsystems. This system has input 4
that comes from input components in the detection subsystem that reads the condition or weather around the device. This input is in the form of values. This system has an output in the form of a value from the input component in the detection subsystem (sensor) which is input to the motor driver to directly collect clothes and there is also a notification that will be received via the application. 2.3 Overview Device subsystem design This tool is a device that can collect and distribute clothes, designed an IoT-based automatic clothesline system and monitors the weather around the device so that it can anticipate clothes being exposed to rainwater. This tool is used to facilitate work in drying clothes based on IoT as a controller and is focused on business actors doing laundry services. 2.3.1 Source of the Nets The conventional mains voltage has a voltage difference of 220 VAC. This voltage is an input from the system that has been made. This mains voltage must first be rectified to a direct voltage (DC) because the electronic equipment used in this device requires a small input voltage value of 12V. 2.3.2 Rectifier Circuit A rectifier circuit is a circuit that converts alternating current (AC) into direct current (DC). There are two types of rectifier circuits, namely half- wave rectifier circuits and full-wave rectifier circuits. Rectifier circuits can be made using diode components. This rectifier circuit requires 4 diodes. The picture of the blue box below is the rectifier circuit. 2.3.3 DC filter circuit The function of the filter on the power supply is to filter the ripple current due to the rectification process which still contains AC current. The 5
filter that is commonly used is a filter with a capacitor. This filter is able to form a waveform output voltage can be flat (constant). The red box image below is the filter circuit. This process requires additional zener diode components. Zener diode is an electronic component made of semiconductors and is a type of diode specifically designed to operate in a reverse bias circuit. When paired to a Forward Bias Circuit, the Zener Diode will have the characteristics and functions as a Normal Diode in general. Basically, the Zener Diode will transmit electric current flowing in the opposite direction if the applied voltage exceeds the "Breakdown Voltage" or Breakdown Voltage of the Zener Diode. This characteristic is different from ordinary diodes which can only transmit electric current in one direction. This Breakdown Voltage is also known as the Zener Voltage. After going through the rectification and filter processes, the resulting output voltage is 12 VDC as shown in the figure below. 2.3.4 Batteries A battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, cell phones and electric cars. When the battery is supplying electrical power, the positive terminal is the cathode and the negative terminal is the anode. In this tool we use the battery as a backup power supply. We use batteries with the consideration that we don't need to recharge them regularly for a short time. 2.3.5 Relays Relay is a switch that is operated electrically and is an Electromechanical (Electromechanical) component which consists of 2 main parts namely Electromagnet (Coil) and Mechanical (a set of Switch 6
Contacts). In this tool, we adjust the relay input to the motor input, which is 12V. Relay Contact Points consist of 2 types, namely: Normally Close (NC), namely the initial condition before being activated will always be in the CLOSE position (closed). Normally Open (NO), namely the initial condition before being activated will always be in the OPEN (open) position. 2.3.6 Microcontroller Microcontroller is a small computer in the form of an IC (integrated circuit) chip and is designed to perform certain operations. A microcontroller consists of a processing unit (CPU or microprocessor), memory, and programmable input and output. The microcontroller in this subsystem functions to process data received from input components such as sensors in real-time and sends the results of the data processing to the Main Station subsystem. With so many microcontroller variants, parameters are needed to select the type of microcontroller that will be selected and used in this system. These parameters include: ● Microcontroller Architecture The microcontroller architecture also determines the capabilities of the microcontroller and the operating system support that will run on it. There are several microcontroller architectures that are commonly used, namely AVR, ESP, ARM, and others. ● Integrated Devices Some microcontrollers have devices that have been integrated into their microcontrollers such as WiFi, and so on. For the purposes of this system, integrated devices are connected to the smartphone application. ● Power Consumption 7
Each microcontroller has a different power consumption. This tool will be connected to the mains electricity and then the voltage will be lowered so that the expected voltage for this tool is 12V and a current of 3 A as input specifications for the motor we use. 2.3.7 Wemos D1 Mini Wemos D1 mini is an ESP266-based mini wifi board which is known to be economical and reliable. This ESP8266 can connect microcontroller devices such as Arduino with the internet via wifi 2.3.8 Sensors Sensors are devices used to detect changes in physical quantities such as pressure, force, electrical quantities, light, motion, humidity, temperature, speed and other environmental phenomena. After observing a change, the detected input will be converted into output that can be understood by humans either through the sensor device itself or transmitted electronically through a network to be displayed or processed into useful information for its users. 2.3.8.1 Light Sensor The sensor used in this tool to detect light intensity is LDR (Light Dependent Resistor). Light Dependent Resistor or commonly called LDR is a type of resistor whose value changes with the intensity of light received by the component. Usually used as a light detector or light conversion quantity meter. Light Dependent Resistor, consists of a semiconductor disc that has two electrodes on its surface. In the dark or dim light, the material of the disc produces a relatively small number of free electrons, so there are only a few electrons to transport electrical charge. This means that when the light is dim the LDR becomes a bad conductor, or it can also be called LDR has a large resistance when it is dark or the light is dim. 8
2.3.8.2 Rain Sensor Rain sensor is a type of sensor that functions to detect rain or not, which can be used in all kinds of applications in everyday life. The working principle of this sensor module is that when there is rainwater falling and it hits the sensor panel, an electrolysis process by rainwater will occur. And because rainwater is included in the liquid electrolyte class in which the liquid will conduct electric current. This rain sensor has a comparator IC where the output of this sensor can be high and low (on or off) logic. As well as on this sensor module there is an output in the form of a voltage as well. So that 5 can be connected to a special Arduino pin, namely the Analog Digital Converter. In short, 2.3.9 Motors DC motors are electric motors that require a direct current supply to the field coil to be converted into mechanical motion energy. The field coil in a dc motor is called the stator (the non-rotating part) and the armature coil is called the rotor (the rotating part). The motor we use is a 12V DC motor. 2.3.10 Load In this tool we also take into account the load that will be driven by the motor. The maximum load capacity on the motorbike that we use is 41 kg, if converted to the weight of the clothes, it is equal to 136 dry clothes or 80 pieces of wet clothes. Other loads included in the calculation besides clothes are the weight of the pulley, rope and PVC pipe as the support for the pulley. 9
IoT Clothesline Collection System Overview
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