Washing Machine Embedded System Analysis

In this following assignment we are going to see about the Embedded system and how it is implemented in home application and there is few reference about the language used in the embedded system and there few application of the embedded system.

Embedded systems are basic electronic devices used to control, monitor or assist the operation of equipment, machinery or a plant. The choice of word “embedded” reflects the fact that these are integral part of the system. Uses of embedded system in our real life are increasing day by day. Children need such systems to play video games and to operate chocolate vending machine; Housewives need embedded systems for microwave, TV, music system, and other system appliances.

ABOUT EMBEDDED SYSTEM:

An embedded device can range from a relatively simple product for ex. a toaster to complex mission critical applications such as those used in avionics. A typical embedded device will have both hardware and software components. The hardware could be micro components such as embedded microprocessor or microcontroller. Microcontroller is relatively small, has an on chip memory, an I/O controller and other supported modules to do processing and controlling tasks. The software consists of applications that perform dedicated tasks and may run on Real time operating system which will be explained later in this unit. Embedded System may be either an independent system or a part of a large system. It is specialized computer system but not a general purpose workstation like a desktop or a computer. Such kind of systems is housed on a single microprocessor board with programs which are stored in ROM (Read Only Memory). Embedded system is usually a compact, portable and mass produced electronic devices. In the early days, embedded systems were designed using microprocessors like 8085. But nowadays, we are using a wide range of processors from other manufacturers. Before we want to the basic of an embedded system, we should see a wide range of its applications. In fact, almost all modern electronic devices use some sort of embedded system technology inside them and we always come across such devices: DVD players, air conditioners, printers, attendance machines, hand phone, digital camera, ATM machines, we will see some examples of embedded system in section 1. Now it is time to give a proper definition.

Definition: “Embedded Systems are devices which are used to control, monitor or assist the operation of an equipment, machinery or plant”. The term “control” defines the main function of Embedded System because their purpose is to control an aspect of a physical system such as pressure, temperature and so on. Also the term “monitor” defines the progress of activities.

Embedded Systems are extremely common in the home, vehicle and the workplace. ·

At Home: Washing Machines, dishwashers, ovens, central heating system, burglars alarms, etc. · Motor Vehicle: Engine management, security (locking or antitheft devices), air conditioning, brakes, radio etc. ·

In Industry & Commerce: Machine control, factory automation, robotics, electronic commerce office equipment’s.

IMPLEMENTATION OF EMBEDDED SYSTEM IN WASHING MACHINE:

Washing machine supports three functional modes:

i) Fully Automatic Mode: In fully automatic mode, once the system is started it perform independently without user interference and after the completion of work it should notify the user about the completion of work. This mode instantaneously sense cloth quality and requirement of water, water temperature, detergent, load, wash cycle time and perform operation accordingly.

ii) Semi-Automatic Mode: In this semiautomatic mode in which washing conditions are predefined. Once the predefined mode is started the system perform its job and after completion it inform the user about the completion of work.

iii) Manual Mode: In this mode, user has to specify which operation he wants to do and has to provide related information to the control system. For example, if user wants to wash clothes only, he has to choose ‘wash’ option manually. Then the system ask the user to enter the wash time, amount of water and the load. After these data are entered, the user should start the machine. When the specified operation is completed system should inform the user.

Remember that Modes should be a selectable by a keypad.

A washing machine may have a System Controller (Brain of the System) which provides the power control for various monitors and pumps and even controls the display that tells us how the wash cycles are proceeding.

Driving Motor

Water pump

System Controller

Display Panel

Sensor

Inverter Unit

The working of these components is as follows:

i) Display Panel: It is a touch panel screen to control all the operations of a machine

ii) Sensor: It measures the water level and appropriate amount of soap. Input devices for automatic washing machine are sensors for water flow, water level and temperature; door switch; selector knob or buttons for settings such as spin speed, temperature, load size and types of wash cycle required.

iii)Water Level Sensor: It indicates beep sound when water level is low in washing tub. Door Sensor: It indicates beep sound when all clothes are washed that means now you can open the maching door and also you can move to your next phase. Next phase will be dry Phase. This phase also follows same concept for drying the clothes.

iv) Driving Motor: Motor can rotate in two directions either “reverse’ or ‘forward’. The forward direction drives the current in forward direction and motor rotates forward. The reverse direction driver does the opposite of it. A washing machine can maintain single motor in fully automatic or double motor in semi-automatic washing machine.

Sequence of washing the clothes with this can be explained in few steps as follows:

1) Put on your dirty clothes on to the wash tub for washing

2) Put the detergent Soap (of your choice like Surf n Excel etc.)

3) Put ON the tap, water rushes inside the tub. Embedded Systems

4) If its electronic control , then by the press of the keys ,you could program , if its mechanical it shall something like an mechanical switches wherein you are allowed to operate for setting the wash time.

5) Now the wash motor rotates and washes the clothes and gives you a beep sound

6) Now your clothes are washed …remove it from the wash tub and put it on the spin tub and program it accordingly…after spinning clothes are dried and you are allowed to hang it for proper drying in sunlight.

The fully automatic also comes in two category front loading as well as top loading.

i) Front loading is the one wherein you are given an opening to put clothes in on the front side.

ii) Top loading is on the top.

iii) System Controller: Such Component is used to control the motor speed. Motor can move in forward direction as well as reverse direction. System Controller reads the speed of motor and controls the speed of motor in different phases such as in Washing, Cleaning Drying etc. All kinds of Sensors such as Door Sensor, Pressure Sensor and Keypad, Speed sensor are also maintained by this.

iv) Water Pump: The water pump is used to recirculate water and drain out the dirty water. This pump actually contains two separate pumps inside one: The bottom half of the pump is hooked up to the drain line, while the top half recirculates the wash water. The motor that drives the pump can reverse direction. It spins one way when the washer is running a wash cycle and recirculates the water; and it spins the other way when the washer is doing a spin cycle and draining the water.

PROGRAMMING LANGUANGE USED IN EMBEDDED SYSTEM:

Embedded systems are application specific computers that interact with the physical world. Each has a diverse set of tasks to perform, and although a very flexible language might be able to handle all of them, instead a variety of problem domain specific languages have evolved that are easier to write, analyze, and compile. The choice of programming language is very important for real time embedded software.

The following factors influence the choice of languages:

A language compiler should be available for the chosen RTOS (Real Time Operating System) and hardware architecture of the embedded system. · Compilers should be available on multiple OSs and microprocessors. This is particularly important if the processor or the RTOS needs to be changed in future.

The language should allow direct hardware control without sacrificing the advantages of a high level language.

The language should provide memory management control such as dynamic and static memory allocation.

So, we can categorize embedded programming languages in to two parts such as hardware language and software language.

Hardware language:

A hardware description language can be used to describe the logic gates, the sequential machines, and the functional modules, along with their interconnection and their control, in a embedded system. There are various languages used for this purpose as follows:

VHDL

VHDL is the Very High Speed Integrated Circuit Hardware Description Language. It can describe the behavior and structure of electronic systems, but is particularly suited as a language to describe the structure and behavior of digital electronic hardware designs; VHDL is an international standard, regulated by the international languages. VHDL is suitable for use today in the digital hardware design process, from specification through high level functional simulation, manual design and logic synthesis down to gate level simulation.

VERILOG

Verilog HDL is one of the two most common Hardware Description Languages (HDL) used by integrated circuit (IC) designers. The other one is VHDL. HDL allows the design to be simulated earlier in the design cycle in order to correct errors or experiment with different architectures. Designs described in HDL are technology independent, easy to design and debug, and are usually more readable than schematics, particularly for large circuits.

Verilog can be used to describe designs at four levels of abstraction:

Algorithmic level (much like, C language code with if, case and loop statements).

ii) Register transfer level (RTL uses registers connected by Boolean equations).

Gate level (interconnected AND, NOR etc.)

Switch level (the switches are MOS transistors inside gates).

The language also defines constructs that can be used to control the input and output of simulation.

Software language:

Java and C++ are other programming languages which are used extensively for embedded system design.

APPLICATION OF EMBEDDED SYSTEM:

We can categorize applications of Embedded System into various categories as mentioned in Table:

Area

Applications

Aerospace

Navigation Systems, Automatic landing systems, Flight altitude controls, engine controls, space exploration

Automotive

Fuel Injection Control, Passenger environmental controls, antilock

braking systems, air bag controls, GPS mapping

Communications

Switches, Hubs

Computer Peripherals

Printers, scanners, keyboards, displays, modems, Hard Disk Drives, CDROM drives

Home

Ovens, Washing Machine, Digital Watch, Security Alarm, Sound Recorder

Industrial

Elevator Controls, Robots, Engine Control

Instrumentation

Data Collection, power supplies

Medical

Imaging Systems, Patient monitors, Heart pacers

Office Automation

FAX machines, Telephones, Cash Registers

CONCLUSION:

An embedded system is a single purpose computer built into a larger system for the purposes of controlling and monitoring the system. These are also known as special purpose computer system. In this assignment we came to know how the embedded system is implemented in the home applications and how it is useful for the human beings in a very good manner.