CONSUMER ELECTRONICS

WASHING MACHINES  Similarly clock circuitry used to time the operation of the machine is
 From the first washing tool, a broom with four fingers at the bottom to considered here to be contained within the controller. It could equally
move the clothes around the bucket, to the modern fully automated well be considered as an external component.
ones, washing machines have come a long way.
 Technological advancements have brought about metamorphic changes
in washing machines.
 From manual washing machines requiring hot water soak before dirty
clothes got churned in machines to semi-automatic with spin dry
facilities to fully automatics.
 Now recently introduced Fuzzy logic the concept of machine wash has
totally changed.
 Multinational companies (MNCs) dealing in electronics have launched
new and modern techniques in washing machines.
 In today's high-stress life a washing machine has become a household
necessity.
 Washing machines are gradually emerging as an omnipresent dhobi in Fig. 1 Inputs and outputs in an electronic washing machine
Indian homes.
 Fortunately the choices are many. Not only in colour, design and  The block diagram is a good starting point for the generation of the
features but also in prices. specification since it shows very clearly the structure of the complete
 Of course the market is flooded with washing machines offering a range system.
of operations.  The block diagram makes no assumptions of the form of the controller.
 From semi-automatic to fully automatic, from top-load to tumble wash, It could be implemented using an electromechanical timer, or a
these state-of-the-art machines promise multifarious, user friendly microcomputer, or a range of other technologies.
features at down to earth prices.  At various stages of the washing cycle the drum is required to rotate at
different speeds. These include:
ELECTRONIC CONTROLLER FOR WASHING MACHINES o a low speed of about 30 revolutions per minute (rpm) while
 The task here is simply to identify the input and output devices used in clothes are washed:
electronic washing machines and to construct a block diagram showing o an intermediate speed of about 90 rpm while the water is
their connections to the controller. pumped out and
 Detailed information about the characteristics of sensors and actuators o a high speed of either 500 or 1000 rpm to spin dry the clothes.
can be added at a later stage.  Let's consider how the microcomputer should control the speed of the
 The block diagram in Fig. 1 shows a possible representation of the motor.
system.  One of the simplest methods of speed measurement is to use a counting
 There are many acceptable ways of representing the system. technique illustrated in Fig. 3.
 It would, for example, be possible to consider the display to be internal
to the controller and therefore not show it separately.

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 It uses a fixed inductive sensor to produce a pulse each time it is passed  The motor power is determined by the timing of the triac firing pulse. If
by a magnet which rotates with the drum. This produces one pulse per the triac is fired at the beginning of each half of mains cycle it will
revolution of the drum which can be used to determine its speed. remain on for the remainder of the half cycle and the motor will operate
 The speed of the motor will be controlled by the power dissipated in it. at full power.
 The simplest way of speed control is to use a triac.  The longer the processor waits before firing the triac, the less will be
 The power could be controlled by some form of electronic circuitry, but the motor power.
the hardware requirement can be reduced if the microcomputer controls  The processor thus varies the delay time with respect to the zero
the power directly by firing the triac at an appropriate time during its crossing point of the mains by an appropriate amount to increase or
cycle. decrease the power in the motor as determined by the difference
 To do this the controller must detect the zero crossing of the ac supply. between the actual and required speeds.
This will require circuitry to detect the crossing point while protecting  This method of controlling the motor speed is very processor intensive.
the processor from high voltages. A block diagram of the system is  It consumes a large amount of processor time and will require a
shown in Fig. 2. considerable amount of effort in writing and developing the software.
 However, this approach uses very little hardware and is thus very
attractive for such a high-volume application.

Fig. 3 Displacement sensors using counting

WASHING MACHINE HARDWARE

Fig. 2 Washing machine control  A system is an assembly of components united by some form of
regulated interaction to form an organised whole.
 At any time in the washing cycle the program determines at what speed  We will examine a microcomputer system, using a washing machine
the drum should rotate. control as an example.
 From knowledge of the required speed and the actual speed as obtained  The units listed below i.e. the washing machine as well as its
above, the controller can determine whether to increase or decrease the mechanical components, electrical units and electronic components are
power dissipated in the motor. known as hardware.

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 The input peripherals consist of (form Fig. 4) HARDWARE AND SOFTWARE DEVELOPMENT
1. Temperature sensor which senses the washing water temperature.  We will now examine how a system is developed. The example used for
2. Safety cut-out switch. this is, of course, a simple washing machine control. The development
3. Keyboard for program selection. will follow the broad pattern shown in Fig. 5.
4. Water level gauge.
5. Motor for washing drum.
6. Power switches for motor, heater, etc.
7. Heater for washing water.
8. Water inlet valve.
9. Water suction pump.
10. Control lamps and indicators.

Fig. 5 Developing the system for washing machine control

 The problem definition is based on the requirements of the

specification. It is also necessary for the redesign of the existing unit. It
is a means of determining what a system's performance is capable of
and what is required from it.
 Data flow charts are used to identify all the hardware elements of a
system at this stage for a general broad picture of the structure of the
installation.
Fig. 4 Washing machine—hardware

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 Program flow charts permit the costs of the necessary software to be
established in the development stage and represent useful aids for the
designer.
 The decision to go ahead with the developments of a system is governed
by economic appraisal and technical feasibility of the plan.
 To establish these criteria the required operating speed, memory storage
capacity and costs of the component parts of the system must be
determined.
 Subsequently the structure of the problem is analysed and the final
production costs deduced.
 There are two alternative approaches for hardware development.
o On one hand, a universal system may be considered which has
not been designed to cope with any one specific problem.
o On the other hand a specially designed system may be decided
upon in which the components used are specially selected for
their suitability to deal with the problem under consideration.
Such optimization is generally not possible when standard
systems are employed.
 For software development a detailed program sequence plan must first
be established. Fig. 6 Data flow chart for a washing machine control
 This is then written in the appropriate code and fed into a computer or
into a development system. TYPES OF WASHING MACHINES
 The program is then translated into the language required by the  Washing machines are mainly of three types, namely
machine and a simulation of the operation sequence is carried out. o washer,
 Any errors found in the program are corrected (this is known o Semi-automatic and
as debugging) and the software is then available for use. o Automatic.
 After the hardware and software has been developed the system  Washers are single tub machines that only wash. Since washers don't
is tested. have the facilities for drying the clothes, these cost less than semi-
automatic and fully automatic machines.
 In semi-automatic machine, Fig. 8, the controls are not fully automatic
and manual intervention is required.
 In fully automatic machines, Fig. 9, no manual intervention is required
during the washing process.
 For automatic machines, programs have to be selected and set by the
user prior to the start of washing cycle. Sensors sense the wash load and

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decide the program ideal for washing the clothes, water level, time ensuring that the repair technician reaches with the right parts to fix it
required to wash, number of rinses and spins, type of fabric etc. without delay.
 Although washer dryer (semi-automatic) machines don't operate with
the efficiency of stand alone washing machines, they offer enormous
space saving.
 However, you have to drain all the soap water before drying.
 Also, you can't wash and dry at the same time and the drying
performance is inferior to that of stand alone machines.
 But then washer-dryers cost less and allow you to wash and dry your
clothes without having to reset the machines.

FUZZY LOGIC WASHING MACHINES

 Fuzzy logic washing machines are gaining popularity.
 These machines offer the advantages of performance productivity,
 Simplicity, and less cost. Sensors continually monitor varying
conditions inside the machine and accordingly adjust operations for the
best wash results.
 As there is no standard for fuzzy logic, different machines perform in
different manners.
 Typically, fuzzy logic controls the
o washing process,
o water intake,
o water temperature,
o wash time,
o rinse performance and
o spin speed.
 This optimizes the life span of the washing machine.
 More sophisticated washing machines weigh the load (so you can't
overload the washing machine), advise on the required amount of
detergent, assess cloth material type and water hardness, and check
whether the detergent is in powder or liquid form.
 Some machines even learn from past experience, memorising programs
and adjusting them to minimise running costs.
 The diagnostic fault-finding system displays a fault code if any problem
arises. You can then convey this fault code to the service centre thus
Fig. 7 Program flow chart for a washing machine control

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 Machines with fuzzy logic microprocessors can be updated as and when
a new technology or program comes up.  High-end machines have a suds-free system including a pressure sensor
 Several models of internet-enabled washing machines have been to detect extra suds in washing if you have used a large amount of
launched. detergent.
 When the network home becomes a reality these machines will allow  The washing machine drains water together with the detergent and then
downloading of new programs and remote fault diagnosis over the refills with minimum water to restart.
direct internet connection.  These machines cost more than regular models.
 Most fuzzy logic machines feature one-touch control.  The foam suppression feature detects whether too much foam is present
 Equipped with energy saving features, these machines consume less during wash and accordingly it either reduces the agitation or adds an
power, and are worth paying extra for if you wash full loads more than extra rinse.
three times a week.  Fuzzy logic checks for the extent of dirt and grease, the amount of soap
 In-built sensors monitor the washing process and make corrections to and water to add, direction of spin and so on.
produce the best washing results.  The machine rebalances washing load to ensure correct spinning.
 In some machines a tangle sensor senses where the clothes are tangled  Else it reduces spinning speed if an imbalance is detected. Even
and takes corrective action by adjusting the water current, so the clothes distribution of washing load reduces spinning noise.
don't tangle further and are cleaned better.  Neuro-fuzzy logic incorporates optical sensors to sense the dirt in water
and fabric sensor to detect the type of fabric and accordingly adjust
wash cycle.

Fig. 8 A typical semi-automatic washing machine (top loading) Fig. 9 A typical fully-automatic washing machine (top loading)

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 CONSUMER ELECTRONICS
FEATURES OF WASHING MACHINES  Washing machines incorporate a tub with heating element and
 The controls and features of a typical top loading washing machine are something to rotate or scrub the clothes in the drum.
shown in Fig.10. The controls of a typical front loading washing  Once the water and detergent are added mechanical action begins
machine are given in Fig. 11. to soak and agitate the clothes.
 Fuzzy logic electronics intelligently improves the wash performance in
washing machines.
1. Capacity: The capacity of a washing machine is expressed in terms
of the wash load, which in turn depends on the type of fabric. It is
expressed in kg. The maximum load for the washer is the amount
that will move freely in the wash tub. Indicative range of weights of
some commonly washed clothes is given in Table 1.
A higher capacity machine offers the convenience of washing more
clothes at one go but consumes more power. Smaller capacity
machines wash fewer clothes and consumes less power, but these
machines can easily fit in a limited space.
2. Wash Programs: High-end washing machines feature different
wash programs to suit different types of clothes. The program
includes regular for normal wash, gentle for delicate clothes
and tough/hard for rugged clothes. In addition, you are able to select
the temperature of wash and the number of runs for better cleaning.
The number of cycles specifies the number of preset
programs available on the machine. This is important for clothes
that require different temperatures.
3. Spin Speed: The higher the spin speed, the dryer the clothes at the
end of the washing cycle and hence the shorter the drying time in the
tumbler dryer. Thus a high spin speed results in
less washing time. Some machines spin at more than 1000 rpm,
some machines spin as fast as 7000 rpm during drying cycle.
4. Washing Technique: In some machines a pulsator disk (Fig.12) at
the bottom, circulates water upwards in large circles while rotating,
providing better and gentler cleaning of clothes. In the agitator wash
technique a rod with fins (Fig.13) is used at the centre of the
washing machine. A rubbing action squeezes the dirt out of clothes.
But it restricts the space and the clothes tend to get entangled.
The tumble wash technique is used in front loaders. A steel drum
Fig. 10 Controls and features of a typical top loading washing machine rotates along a horizontal axis and the clothes rub against its metal

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 CONSUMER ELECTRONICS
surface due to centrifugal action. The cleaning is, of course, superior In LG punch + 3 technique the water punch propels the detergent
but there is a risk of ruining gentle fabrics. rich water vertically into every thread of the fabric. The action is
supported by three mini pulsators which work with the main
pulsator to generate powerful micro water-eddies. The mini
pulsators rotate in the opposite direction to the main pulsator. This
helps in reducing entanglement of clothes, resulting in less wear and
tear and better wash technology.
5. Loading the machine: Top loaders (Fig.10) allow you to easily
remove clothes, without having to bend even during power failure.
These are compact and require normal detergents. You can add
clothes even during the wash cycle. The larger the porthole, the
more convenient the loading and unloading. Most top loading
machines have an agitator.
Front loaders (Fig.11) are usually more expensive than top loaders
as these incorporate heftier motors and suspensions. However, these
machines consume less water and dry clothes much faster, thereby
reducing energy bill. The hot wash option allows better cleaning.
You cannot open a front loader midway through a wash cycle. You
need to use detergents producing less lather and if the power fails
you can't open the door due to water in the drum. Also you need to
leave room for door opening/closing on the front side.
6. Automation : On fully-automated washing machines you don't need
to wet your hands, just put in the wash load, turn the machine on and
wait for it to finish washing and drying. Automatic machines require
a dedicated running water supply from a tap. A single tub carries
out all the actions. The washing machine does washing, rinsing and
drying and beeps when it is through with all the tasks.

Fig. 11 Controls and features of a typical front loading washing machine

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 CONSUMER ELECTRONICS

Fig.12 The pulsator disk

Fig.14 LG punch +3 technique

Fig.13 The agitator rod

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Table.1 Indicative Range of Weights of Some Commonly Washed Clothes 4. Compare top loader and front loader washing machines.
Approximate 5. What are the different types of washing machine?
Clothes
weights 6. What is rinse cycle in washing machine?
Shirt 200 gm – 300 gm 7. Write any two features of washing machine
Trousers 350 gm – 500 gm 8. What is a drum motor?
Pyjama 300 gm – 400 gm 9. Define fuzzy logic.
Kurta 200 gm – 300 gm 10. What do you mean by program flow chart?
Lungi 200 gm – 300 gm 11. Mention any four parts of washing machine hardware.
Vests 75 gm – 100 gm 12. Mention the operating principle of a washing machine.
Underwear 100 gm – 150 gm
Socks 50 gm – 75 gm PART B
Dhoti 200 gm – 250 gm 1. Draw and explain the block diagram of washing machine.
Saree 300 gm – 500 gm 2. Explain the features of washing machine.
3. Discuss the different types of washing machines.
Blouse 100 gm – 150 gm
4. Discuss the basic hardware parts and its functions used in washing
Petticoat 350 gm – 450 gm
machine.
Undergarment 75 gm – 150 gm
5. Write a note on Fuzzy logic washing machines.
Nightgown 200 gm – 300 gm
6. Explain the working of electronic controller for washing machine.
Salwar Suit 350 gm – 500 gm 7. Describe what are the hardware and software used in washing machine.
Frocks-Baby 200 gm – 300 gm 8. Give the miscellaneous features of washing machine.
Frocks-Girl 350 gm – 450 gm 9. Draw the electronic controller flow chart for washing machine.
Skirt 200 gm – 300 gm 10. Give a detailed description of the motor and its specifications for use in
Sweater 500 gm – 800 gm washing machines.
Bedsheet Double 1000 gm – 1200 gm 11. Contrast the working of a top loading machine with a front loading
Bedsheet Single 400 gm – 600 gm washing machine.
Towel large 700 gm – 1000 gm
On semi-automatic machines you have to manually transfer the clothes PART C
from the washer to the dryer. Semi-automatic machines featuring 1. Classify the various types of washing machine? Explain its working.
microprocessor based controls with feather-touch buttons consume less 2. Describe the working of a neuro fuzzy logic washing machine.
power and are preferable where running water is not available. 3. What is FUZZY logic? Briefly describe how it is used in washing
machine.
QUESTIONS 4. Explain the working of electronic controller for washing machine.
PART A 5. Describe in detail, the electronic controller flow chart for washing
1. List out the process controlled by Fuzzy logic. machine.
2. What is air dry cycle on washing machine? 6. What are the different types of washing machine? Explain in detail.
3. Write down any two features of washing machine.

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