D&T: Electronics and Control Systems

Unit A511: Introduction to designing and making

Name: Ismael Munir

Candidate number: 9111

Centre Number: 16527

To feel safe

Investigation of Users’ Needs

1.Are you worried about your sheds security?Explanation: To engage the conversation2.Have you got any shed security devices already?Explanation: To see if there is a gap in the market and if they really need my product3.Has your shed got any valuables in it? Explanation: So I know if they need it protected4.Have you been robbed before?Explanation: To make sure it doesn't happen again5.Has there been a robbery in your neighbourhood recently?Explanation: To see if there is a need in your area and to protect the customer beforehand6.Do you have insurance on your belongings?Explanation: To see if they need this product because they don’t want it stolen7.Is your shed far away from your house?Explanation: Because it would be less likely for them to know that they have been burgled. 8.Would you buy one that was easy to use?Explanation: To see if they can install it and if there is a need for it9.How much would you pay? a.£1-£10 b.£10-£20 c.£20+Explanation: To see how much I could/should market it for 10.Do you live in a isolated area?Explanation: To see if the product works in isolated areas.

Questionnaire (Questions+ Explanations )

Questionnaire (Tally)Questions YES NO

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4. /// ///////

5. // ////////

6. /// ///////

7. /////// ///

8. //////// //

9. a./// b.//// c.///

10. //// //////

This determines that I need:• An easy to use setup• Easily understandable instructions• There is a gap in the market• It needs to be loud so they can

hear it from further away

Product CostTypical user

When / Where used?

FunctionTechnology

used(Input / Output)

Manufacturing process

used

4 PC PIECE DOOR WINDOW INTRUDER

SECURITY ALARM £5.97

The typical user would be

somebody looking to protect they’re belongings by an

alarm through there window.

The function would be to deter a burglar from entering your

house using an alarm.

Input: 4 AA batteries.

Output: loud siren

Assembly line

Night watcher NW300 Robotic

Security Light with Wireless Alarm

£79.98

The typical user may be a home

owner. This will be enabled at night or

when away from home or on holiday.

The function would be to shine a light

which would effectively scare

potential burglar's away.

Input: Specifications

Detection Method Passive Infrared Sensor Material CastOutput: Light

Bulb (150 watts)

Assembly line

Friedland Response SL1 Home and Away

Wire free Burglar Alarm System

£102.90

The typical user may be a house or

apartment/flat owner . This will be enabled at night or when you are on Holiday or away

from home.

The function would tell nearby people that your house is

being burgled.

Input: 2 (PIR) detectors

Output: 1 solar siren with LED

indicators

Assembly line

The cheaper the product, the less valuable the thing it is trying to protect

Design brief

I am going to design a product which detects when a person is intentionally breaking into a shed, then alerts the owner and those around the house if they are away.

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

In the next few slides I am suggesting and reviewing products which fall along similar lines as the product which I will hopefully create, from well known online retailers and DIY stores such as Amazon and Wickes.

Response alarm(B&Q)£15.98

• Ideal for protecting your shed, garage or outbuilding

• features• Brand: Response• Colour: White• Link To TV (Y/N): No• Warranty/guarantee: Guarantee• Warranty/guarantee details: 1 Year• Manufacture part no: ML1• Category: Other CCTV & Alarms• additional information• Easy to install• Keypad operated with 20 second entry / exit

delay• Pre-wired door contact• Tamper protection• Recording (Y/N): No

Motion Sensor Alarm/ Home/ Garage (Amazon)£7.40

Technical DetailsThis easy to install motion sensor alarm includes 2 remote control key-rings5m range and wall mount.The main unit requires 4 x AA batteries (not supplied) or alternatively, a 6V adaptor can be usedThe remote units come supplied with 3 x AG13 button cell batteriesThis is an ideal burglar deterrent Product DescriptionRemote Controlled Infra Red Alarm. This cordless, movement activated alarm will alert you to intruders on your property, in the garage, outbuildings, sheds etc. The built in motion sensor detects movement up to a 6m area and will sound a loud 110dB alarm to alert you and hopefully scare off the intruder. Easy to install (fixings and mounting bracket supplied) it requires no wiring, adjusts to any angle and is simple to use. The infra red remote control will arm and disarm the system. The main unit measures a compact 5ins x 3ins x 2ins and requires 4 x AA batteries (not supplied) and the remote control requires 1 x 12v (supplied).

Friedland Mini Entry Alarm (Wickes)£9.99

• Remote controlled alarm - sounds when any movement is detected in room

• Easy to install• Mounts on wall• Mounting bracket and

fixings supplied

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.• This could best be done as a table for top marks:

Specification Feature Reason for need for Feature Evidence from research for need

Needs to be powered by a 9 volt battery.

So that it can be portable and safe to use.

All the products I’ve seen are portableMy survey showed batteries are preferred.

Specification • The purpose of my product is to detect when a person touches the handle of a shed, then proceeds to

open the door with the intention to steal from it. This triggers the products alarm that effectively scares the burglar away. More than less people on my questionnaire would prefer this.

• The proposed product should detect when someone has their hand on the doors handle. This is so it prevents the burglar taking valuables from the owners shed. The proposed product should sense the person touching the door handle. This is so it notices the person trying to steal quickly and effectively.

• The products output should be some sort of siren. The reason for this is so that people know the shed is being burgled.

• The power supply for the product will be an AA 9v battery. This is because this is the safest thing to run it with.

• The circuit will be run on a 9v voltage. This is because this is the only way we have on the premises. The product will have an on/off switch. The reason why it has an on/off switch is because when someone tries to open their own shed, the do not want the alarm to sound.

• The product will not have an indicator, it will have instructions as to when it is alive. The product will be designed on circuit wizard. This is because it is an efficient way of testing how a circuit will work.

• The circuit will be manufactured using CAD soldering and also PCB, as these are the only available ways of manufacturing it. The way that we are going to ensure if it works is we will test it on circuit wizard, then make a sample on a PCB and solder it, then test it in a scenario to see if it works. I am taking such precautions because we need to get the circuit done first time around without fail or faults in it.

System diagram Input Process OutputDelay BeforeInput(s)

input1 combine input2 Delay afterinput

Process DelayBefore output

Sound etc.

None Heat OR moisture none thyristor none LED

5 dark none Reedswitch

5 Monostable 5 Buzzer

10 light AND moisture 10 Transistor 10 Motor

15 PTMswitch

NOR light 15 MOSFET 15 Dual LED

20 Reed NAND dark 20 Astable 20 Siren

Similar circuits 1 heat sensorCircuit 15 - Heat Sensor (Transistor).As temperature increases, the LED will light at a certain degree of heat, which can be set by adjustment of variable resistor.

Similar circuits 2 Intruder Alarm

Circuit 78 - Intruder alarm.

In the event of either of the two sensors being activated, i.e. if a window or door is opened, the buzzer will sound and continue to do so until switched off by owner of the house.

Original idea

Developed (1)

Final circuit

These are the two situations which could happen while using this circuit, when the light goes off and the buzzer comes on it means the temperature has risen to high

Other option of final circuit

Planning for testingStep Expected

outcomeReaction Actual

outcomeResult

Turn it on Red LED should come on

Red LED comes on to show the user that it works and is on.

Red LED comes on

Wait until temperature rises past body heat

If door opens also, alarm should be set off

Alarm goes off to tell the user they are being burgled until being turned off

Alarm set off

Door opening detected

Alarm should be set off

Alarm goes off to tell the user they are being burgled until being turned off

Alarm set off

PCB stage 1

This is what circuit wizard originally made my PCB into, just with the copper board removed. It does exactly what it is supposed to do which is: The switch is supposed to represent a burglar gripping a doorknob creating a rise in temperature. The red LED should stay on until the temperature is increased past 31 then the buzzer should sound. I have set the temperature there because it is close enough to body temperature to be set off.

PCB stage 2This is a slightly modified version of the first one ,as you can see the wires are straighter which will make the etching easier for the service.

PCB stage 3

This is the final version of the PCB which I am creating, I have made the circuit smaller so I can use less copper making the wire in my circuit. All the components are placed safely in a position in which I know will work. I have also changed the MOSFET to a thyristor and added a reset switch so that it can be switched off safely without having to disable the circuit. I have removed the terminals because they will not actually be there when the circuit is made.

Planning for testing (final built product)

Step Expected outcome

Reaction Actual outcome

Result

Turn it on Red LED should come on

Red LED comes on to show the user that it works and is on.

Wait until temperature rises past body heat

If door opens also, alarm should be set off

Alarm goes off to tell the user they are being burgled until being turned off

Door opening detected

Alarm should be set off

Alarm goes off to tell the user they are being burgled until being turned off

Planning the manufacture processProcess description Equipment required Safety issues Tips for success

Design PCB and mask Circuit Wizard program None None

Cut board to side Band saw The saw’s blade is sharp so you could cut yourself

Make sure it is placed correctly

Expose mask and PhotoPCB to UV light

UV light, Photo PCB, Mask of my circuit

Don’t look directly into UV light. Expose it to air for 10 minutes afterward

Develop exposed PCB Development fluid Make sure it doesn’t splash on to you as it could be harmful.

Wear the safety equipment

Etch PCB Bubble etch tank, Etchant The etchant is corrosive Make sure you do not burn the circuit

Drill holes Drill The drill moves fast so be careful it doesn’t scratch you.

Make sure the drill bit is where you want to drill

Solder chip socket Soldering equipment, Chip socket

Soldering iron tip is hot so do not touch it

Make sure pins are all in correctly

Solder resistors Soldering equipment Soldering iron tip is hot so do not touch it

Make sure pins are all in correctly

Solder capacitors Soldering equipment Soldering iron tip is hot so do not touch it

Make sure pins are all in correctly

Solder MOSFET Soldering equipment Soldering iron tip is hot so do not touch it

Make sure pins are all in correctly

Solder off board components Soldering equipment, wires Soldering iron tip is hot so do not touch it

Make sure pins are all in correctly

Shrink wrap connection between off board components and wires

Heat gun, heat shrink tubing The heat gun is hot Solder the tubing for a few seconds

Add chip to socket chip Make sure you don’t put it in the wrong way

Bill of materials

Making the circuit

Making the circuit1.

2.

1. In this picture there is my circuit board with some of the components placed in their respective positions. There are 2 variable resistors, 2 resistors and a thyristor. The off-board components currently on there is the LED at the bottom and the switch at the top. I had to make sure that I put the black and red wires in the right way because they represent positive and negative.

2. In this picture there is my circuit board with no components on, just after being etched. Some off the holes have been drilled bigger so that my components can fit in more comfortably.

Making the circuit 21.

2.

3.

1. This is my LED just before it has had the shrink wraps placed on to it. I have soldered the wire to the LED and made sure I put positive and negative on the right legs.

2. This is a wire after it has been twisted and tinned so that it can be attached to the switch.

3. This is my switch after it has been shrink wrapped, it doesn’t matter which peg you put the wire into on the switch as long as you put one on the middle peg.

Making the circuit 3

1.

2.

1. In this picture I am shrink wrapping a switch using a heat gun. You have to be very careful whist doing so because if you are not, you could get burnt.

2. In these pictures there is my circuit almost done with the components soldered in well

Making the circuit

1.

2.

1. This my soldering of the components and the battery wire has been wrapped around the end so that it is attached properly.

2. This is the soldering of my chip. You can see that most of the sockets have been soldered well and that one has been joined, but it is okay because there is a copper wire running through the joined sockets.

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.• Provide a video showing it working so that it is clear that it solves the

problem. Use Blueberry Flashback Recorder).

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