D&T: Electronics and Control Systems

Unit A511: Introduction to designing and making

Name:

Candidate number:

Centre Number: 16527

Creativity (slide 2)

Theme Choice• Choose and state the theme for the project.• Explain why you have chosen it.• Use a mind map (spider diagram) explore possibilities. Show a range of possible

problems and situations related to the theme.• For example:

• Choose one to develop for your project – show your choice on the chart

This could be hand drawn and scanned into your presentation

USERS NEEDS

WHEN

WHO WHY

WHERE

WHAT

Investigation of Users’ Needs

Designing (slide 3)

Creativity (slide 4)

Users Needs• What does the user need to solve the problem you have identified?• Evidence that there is a need (WHAT):

– Annotated pictures– Newspaper clippings describing what happened (most articles will state what happened, who it

happened to and probably where.

• Evidence of users (WHO):– Brief survey– People in newspaper clippings

• Evidence of the situation (WHERE)– Pictures showing where there might be a problem and where the solution you propose might be used.

Creativity (slide 5)

Carry out a brief questionnaire

• Produce 10 questions that will help discover information that will show that people exist who have the problem you are exploring.

• Get 10 people to answer your questions.

• Ask questions to identify WHAT the problem might be.

• Ask questions to identify WHO might have the problem and might want your product.

• Ask questions to identify WHEN and WHERE the problem might be.

• Ask questions to identify the nature of the possible solution. (This might help you draw up your specification.

• Don’t forget to explain why you ask each question – don’t ask pointless questions that you will not learn anything from.

• Make sure you do a tally of the results and explain what they show

Creativity (slide 6)

Product Comparison• Analysis of products related to the theme.• Three pictures of products related to the theme. The analysis should show a trend,

such as cost complexity or type of user. (Probably 3 different types of security device.)

• The table below could be used. (See the next page for some examples)

Product CostTypical user

When / Where used?

FunctionTechnology

used(Input / Output)

Manufacturing process used

Name and picture of product 1

Name and picture of product 2

Name and picture of product 2

Product Description – Personal Attack Alarm (£5.99) - From AmazonTiny matchbox sized attack alarm with a useful key ring attachment. Simply pull pin out to activate alarm. Emits 130 decibel siren Supplied with alkaline battery 5 year no-quibble guarantee. Size: 4.4 x 3.8 x 1.6cm Weight: 20gms .From Amazon

Product Description – Carbon Monoxide Alarm (£16.66) - From AmazonRequires 3 X AA Batteries, LCD Display, Approved Test and hush button Alarm memory function, Audio and visual Alarm, Self test function, Highly accurate carbon monoxide detection, Audibility: 85DB @ 1 metre distance Sound and LED indication Standby: Green LED flashes once every 30 seconds Alarm: Red LED flashes quickly with alarms sounding every 5 seconds and repeat Low battery indicator: Sounds every 30 seconds when batteries are lower than 3.3v with green LED, Malfunction indicator

Product Description – Cold Alarm for Old People (£27.50) - From AmazonKeep warm and stay safe with this affordable and effective alert to the dangers of falling temperatures. Particularly useful for the elderly and less mobile, who are often especially vulnerable and cannot always detect or respond to getting cold, this Cold Alarm provides early warning of colder conditions in the home, so you can take simple steps to prevent ill health. The Cold Alarm delivers early warning of falling temperatures in the form of an easy-to-understand traffic light style LED display, which is backed up by an audible alarm at the lowest temperatures. Green light flashing every 10 seconds shows that the temperature is above 18°C : considered normal safe environment; Amber light flashing indicates that the temperature is between 12°C and 18°C :take action to increase warmth; Red light flashing warns of a dangerously low temperature of between 7°C and 12°C : there could be a risk of hypothermia, need to take action; Red light flashing and beeping alarm alerts to immediate danger of a temperature below 7°C : dangerously cold.

Examples of products for comparison (all alarms of some sort)Remember these are examples – you need to get your own

Creativity (slide 7)

The Design Brief• Summarise what you have found out so far in terms of there being a definite

situation, a recognised problem and people who have a need for what you could design to help them.

• Write a clear Design Brief that describes clearly what you are going to design and make.

• Write down what you need to do next or find out next e.g.– Decide in detail what your circuit is going to need to do to solve the problem.– What circuits and components might be available for you to use.– What software you have available to you, to help you solve the problem and design a solution.

Creativity (slide 8)

Product Analysis• Analyse in detail 2 products related to your project (probably 2 different types of

burglar alarms, one fairly simple and one a little more complex.)• Use the table on the next slide to help you organise the information.

A simple system for the hotel room on holiday.

A more complex system for the home.

Creativity (slide 9)

Name and picture of product 1 Name and picture of product 2

Function

User need fulfilled

Materials used in construction

Durability of product

Sustainability (6Rs)

Life cycle

Energy use

Use 10 or 12 point text in this table

Design (slide 10)

The Specification• Summarise the information to produce a list of points that describe what your

“product” will need to be like to solve the problem.• Remember that you are only describing what the circuit will need to do to solve the

problem.• This list of points is the “specification”• Function:

– What it needs to sense – inputs– What it needs to do when whatever is sensed – output– Include any timings if appropriate – delays etc.– Include indicators etc.

• Power supply.• Safety features.• Manufacture / construction.

Design (slide 11)

System Diagram• Show a systems chart to show possible inputs, outputs and processes.• Show pictures of the components required for each input or output mentioned.

• Do not include combining inputs and delays if not appropriate to what you are designing – although you could use the columns to show that the response is immediate. (i.e. 0 seconds.)

Delay before INPUT

INPUTCombine inputs?

Delay after

INPUTPROCESS

Delay before

OUTPUTOUTPUT

Time delay between power on and input sensed?

Delete these instructions from your table.

List of possible things that could be sensed + images of possible components.

More than one input that needs combining? – e.g. AND or OR?

Time delay after input sensed?

List of possible ways that the output can be controlled.

Time delay before the output is turned on.

List of possible outputs ( include power indicators etc.) + images of possible components

Design (slides 12 and 13)

Slide 10 – Ideas for the circuit• Include 3/4 circuits that could solve the problem:

– Picture of each circuit – from internet, hand drawn and scanned in or from circuit wizard.– Brief description of the circuit saying what does in terms of what it senses and how it

controls its outputs.– How well it could it solve the problem?

Slide 11 – Development of the chosen circuit• Choose one circuit and give your reasons for choosing it.• Build it in circuit wizard

– Show screen shots of the circuit being developed – component values being changed to fine tune the way it works (especially in terms of timing delays etc.)

– Show annotated screen shots of the circuit being tested to show that it will work and that it will solve the problem.

• It is important that at least three annotated stages are shown of the circuit being developed, that the screen shots show it working so that it is clear that it solves the problem.

Design (slide 14)

Development of the PCB• Show the stages of the development of the finished circuit into the final

PCB• You must show at least 3 stages of development.• Each stage must be annotated to describe the changes and the reasons for

them.• The final PCB must be shown including the off board components and the

connecting wires – it would be a good idea to label this final stage.• The list of components must be included – images of the components to be

used could get extra marks. (from earlier in the project?)

Making (slide 15)

Planning for manufacture• Use the table below to describe how you plan to make your circuit.• Use the information and pictures of equipment on my website to help you.

Description of Process Tools/Materials required Tips for successDesign PCB and create mask

Cut board to size

Expose Mask and photoPCB to UV

Develop exposed PCB

Etch PCB

Drill holes in solder pads

Add resistors

Add capacitors

Add transistors/thyristors

Add Chip socket

Add off board components

Add chip to socket

Delete any of the processes that don’t apply

You need to add detail to this column for each process

Making (slide 16 to 18 - approx)

Manufacture of the circuit• Include photographs to show the stages of the making of your circuit• Annotate each picture to show what is happening.• Highlight any problems that were encountered and what you did to solve the

problem or anything that you changed as the circuit was constructed (i.e. what is different to what you planned. This is an important part of the mark scheme.

• In addition:– You must include a clear photo of the whole circuit including the off board components and the

connecting wires.– You must include a clear photo of the top side of the PCB showing the components.– You must include a clear photo of the underside of the PCB showing the soldered joints.

• To ensure the marks for problem solving are gained it might be best if the changes mad and the problems encountered are summarised at the end of this section.

Evaluation (slide 19)

Testing your circuit• Show a step by step plan that can be used to test your finished circuit.

Write it as if it were for a person who does not know how it is supposed to work.

• Tick of each step to show that the circuit works.Evaluation• Describe what went well and what did not go so well in the manufacture of

your circuit– Consider the development of the circuit and the development of the PCB– Consider the actual building of the circuit

• Could it have been made differently? – alternatives?• Could it have been made better? – how?• Compare what you did to the steps of your plan• See table on next slide as a suggestion.

Evaluation (slide 20)

Evaluation (continued)

Description of Process What went well Problems encountered/changes made

Action taken to deal with problem

Design PCB and create mask

Cut board to size

Expose Mask and photoPCB to UV

Develop exposed PCB

Etch PCB

Drill holes in solder pads

Add resistors

Add capacitors

Add transistors/thyristors

Add Chip socket

Add off board components

Add chip to socket

Copy the planning table and edit as required.Comments only need to be brief.

Evaluation (slide 21)

Improvements• In addition to describing how the circuit could have been manufactured

better;• Describe how the circuit could be improved to function better to solve the

problem more effectively.– Different inputs– More inputs– Different control of the outputs– Different outputs