there is an increased awareness of the importance of safety in the home for both adults and...

There is an increased awareness of the importance of safety in

the home for both adults and children. Items such as personal

alarms, child locks, burglar alarms, warning devices,

temperature alarms etc. help to create a safer environment.

Design Brief:

With reference to the above theme, design and make a device

that will improve personal safety in the home. The device must

incorporate a mechanical or electrical or electronic system.

Theme: A Safe Environment

Theme: A Safe Environment

There is an increased awareness of the importance of safety in

the home for both adults and children. Items such as personal

alarms, child locks, burglar alarms, warning devices, temperature

alarms etc. help to create a safer environment.

Design Brief:

With reference to the above theme, design and make a device

that will improve personal safety in the home. The device must

incorporate a mechanical or electrical or electronic system.

I have decided to carry out some research on the following

topics:

• Personal Alarms

• Burglar Alarms

• Child Locks

Warning Devices / Alarms?

Children Elderly

HandicappedSingle People

Safety Concerns for!

Fire! Security!

I have decided to focus on the handicapped environment!

(1) Analysis, Research & Investigation:

HearingDisability

Elderly

Visually Impaired

Wheelchair Bound

Safety Concerns for!

Handicapped


Hearing Disability

Associated Problems:

• awareness of caller - door bell / knocking! • telephone ringing• television / radio• cooker alarm• smoke alarm• intruder• dog barking

I have decided to investigate a visual/vibrating indicator to indicate to the impaired hearing that someone is at the door.


The number of personal attacks particularly on the elderly

and young women is quite frightening in today's society.

Therefore there is a need for some type of small convenient

device that could be easily carried, triggered with ease and would

send out a loud audible tone to catch the attention of passers-by!

I have decided to carry out some research on the following areas:

• Personal Alarms• Burglar Alarms • Warning / Signalling Device


http://www.wirelessretail.co.uk/index.php


A Domestic Burglar Alarm:The idea of an intruder alarm is to simply try and deter a potential burglary occurring at your premises, and to an extent research shows that it works. A burglar does not want any attention; his/her aim is to access the property with as little fuss as possible. If the alarm system is triggered or activated a loud sound attracts attention!

Warning Device:I may consider researching some type of warning or signalling devices such as hazzard lights – safety – tractors, cycling, walking etc. or a device to aid the handicapped?

Design 1: Existing Solutions

This alarm is designed to be worn around the neck or strapped to the wrist for convenience. It is very compact, small in size and quite robust. The casing is made from ABS, nylon etc, and the manufacturing process is probably injection moulded however this shape could be easily made using the school vacuum forming machine and using rigid polystyrene plastic. The shape or design is quite simplistic and uninspiring.


This personal attack alarm opposite also performs exactly the same function producing a high pitched sound dB120 for a short time warning off an attacker or an alarm! I like the relief detail that I feel enhances the visual impact!




Specification – (must do’s)

Compact, lightweight, plastic casing, robust, aesthetically

pleasing, relatively low cost etc..

This alarm is designed to activate when the cord is pulled.

The cord is easily accessible. The cylindrical shape lends

itself to accommodate the round batteries. This design is

very small and probably quite comfortable to wear around

the neck. The wearer can be assured that the device is

always readily at hand and not left in the handbag or in the car!

A Domestic Burglar Alarm:

This diagram shows the different locating zones in and around the home for the many different alarm devices that could be fitted to help provide better security – sensors, motion detectors, monitor


(1) Analysis, research & investigation - existing products

An existing product in the market place:

The Evo D413 is a wireless door bell/flasher system for use throughout the home and garden. The bell push is fitted to your door like any conventional door bell, but the chime/flasher unit is wireless making it fully portable up to a range of 200 metres. This system is also designed with the hard of hearing in mind with a flashing light built in for use instead of the chime. I like the range that this device provides however the LED light output may be difficult to see and the circuit appears to be quite complex!

Evo D413 Wireless Flashing Door Bell Kitfor the hard of hearing

Type of device will require either something flashing or moving?

Some type of Mechanical or Electronic system.

My Design Brief:

My intention is to design and manufacture a device

which will signal to a partial hearing person that

someone is at the door. I also wish to include a

security alarm that indicates an intruder has entered

the property.

(1) Design Specification: Door-Bell / Security:

Design Specification:

• the device should be operated by a standard door-bell push button;

• when the button is pressed the device should continue to operate for a minimum of 10 -15 seconds;

• the visual output signal must be easily seen indicating someone at the door;

• a visual signal must indicate should an intruder enter the house;

• if the device is operated by electronics it should be powered by low voltage d.c. (less than 12V);

• the device should be easily manufactured in the school workshop;

• the product should be attractive, easily serviced and maintained;

• the product should be strong and withstand sudden shocks.


Design Specification continued:

• the product / device should hold a TV remote control;

• the unit should be compact, stable and match the room

surroundings;

• the product should be environmental friendly.


(2) Project Management:

Proposed Timeframe: -

Time: - 49 class periods to complete the portfolio & manufacture the product;

Budget: - I have estimated that 10 euro should cover the total production costs;

However my research will be helpful when costing materials and my chosen design may also impact on the final cost.

Circuit 1: Systems Design Ideas

Pros:

• a very simple circuit which provides oscillating sound and flashing light / LED

Cons:

• operator might only press the door button momentarily

• Needs to sound and flash for at least 10seconds

A very basic electronic circuit design

Pros:

• a very simple latching circuit which uses a relay to create a latch

• Light will continue to flash until the door is opened (SW 2)

• No electricity is used until the switch (SW1) is pressed

Cons:

• when no one at home light will continue to flash and sound - power wastage

• Relays can stick over a period of time

Circuit 2: systems design ideas

A basic electronic circuit design


Pros:

• a simple latching circuit using a thyristor

• Light will continue to operate until the door

is opened (SW 2) • This circuit design is

more reliable than a relay

Cons:

• when no one at home light will remain on wasting battery power.

A basic electronic circuit design


Pros:

• this basic circuit design uses a capacitor to keep the light flashing for approximately 10 seconds

Cons:

• capacitor timing tends to be inaccurate

• slight current drain through LED and transistor.

A basic electronic timer circuit design

This circuit provides a delayed visual indication when a door bell switch

is pressed. In addition, a DPDT switch can be moved from within the

house which will light a lamp in the door bell switch. The lamp can

illuminate the words "Please Wait" for anyone with walking difficulties.


This circuit also satisfies the conditions for the security / door bell situation:-

• SW 2 ‘on’ LED D1 flashes;• capacitor charges and provides current to the LED for approximately

15 seconds;• If SW 3 micro / proximity switch (fitted into the door) is activated D2

flashing LED indicated an intruder has entered.


This circuit also satisfies the conditions for the security / door bell situation:-

• SW 1 ‘on’ and SW 3 door bell ‘on’ Bulb BL1 ‘on’;• thyristor latches keeping BL1 ‘on’ indicating someone at the door;• SW4 pressed BL1 ‘off’ current by-passes thyristor switching this

component to its insulating state;• If SW 2 micro / proximity switch (fitted into the door) is activated D3

flashing LED indicates that an intruder has entered.

Circuit 5: optimum electronics systems design

Circuit 5: optimum electronics systems design

PCB converted using Circuit Wizard

Location of unit?

Near the TV as this would be central in the room? The casing should also be a decorative unit / product;

Worn on body would be ideal but this would require infrared / radio which is too complex an electronic system.

My Design Brief:

My intention is to design and manufacture a device which will signal to a partial hearing

person that someone is at the door. I have decided to design the systems casing or

housing as a TV remote control holder or stand as this often is in a convenient location

and easily seen in the living room. An output light will indicate when someone is at the

door. I also intend to design some type of security alarm to indicate that an intruder has

entered the house.

(3) Design Ideas: Security / Door Bell Indicator

Location of unit:

Near the TV as this would be central in the room?

Caller calls at the door and rings bell

a) A flashing light signal indicates that someone Is at the door

b) A flashing light of a different colour flashes if an intruder enters the house.

The unit is placed near the TV In a central location.

A TV remote holder/stand Could be duel purpose?


Location?


I feel the best location for this product is near the TV which tends to be the focal point in the living room.

Someone at the door

Alarm!!An intruder has entered

Concepts: Early Ideas Casing Design

supporting the TV remote control

Side view end view

Some type of stand made from acrylic plastic?

Concepts: Early Ideas Casing Design

Gouging from a solid pieceOf wood

supporting the TV remote control

Concept 1: Early Ideas Casing Design

Designing from a solid block of wood

Holder for the TV remote control

Concept 1: Solid Modelled - 3D CAD

Casing made from solid beechThis design could be manufactured usingthe CNC. Access for the battery & pcb will must be considered!

I may decide to manufacture this design Using the press-mould method.

The remote control sits on the acrylic rest & the large LED provides the flashing output when someone rings the door bell.

I drew my inspiration from the shape / profile of the remote control.


This a simplistic casing design that may be vacuum formed or press moulded.

The remote control is located in the recess.

Inspiration taken from …!!!

LED light

output


(3) Selection of Optimum Solution / justification

Justification:

I have selected this design as it satisfies all the points raised in my specification:-

the device should be operated by a standard door-bell push button;

My electronic circuit demonstrates that when the door is forced open or when the door bell is pushed flashing light/s provide a signal to the user;

when the button is pressed the device should continue to operate for a minimum of 10 seconds;

The capacitor in my circuit acts like a battery and provides current to flow to the output for a required time;

the visual output signal must be easily seen indicating someone at the door;

I have inserted flashing LED’s into the TV remote control and I find they are easy to see particularly when placed on the TV remote stand centrally in the room;

a visual signal must indicate should an intruder enter the house;

When an intruder forces the door open the proximity or micro switch / magnet in the door holding the switch open is released and makes contact bring the circuit on – flashing LED ‘on’;

if the device is operated by electronics it should be powered by low voltage d.c. (less than 12V);

The device is powered by a d.c. 12V battery;

the device should be easily manufactured in the school workshop;

All the making process using acrylic plastic such as drilling, filing, bending, gluing etc can be carried out in the workshop;

the product should be attractive, easily serviced and maintained;

I feel the product looks good because of the contemporary design and the colourful acrylic material and I also feel it fits into the domestic environment quite well.

(3) Selection of Optimum Solution / justification

Concept 3 sketch development:

Some type of fabricated housing would conceal the battery and pcb and add stability?

I will require some type of robust stand and baseto house the remote securely?

Concept sketch development:

I like the idea of a housing so I have designed this simplistic shape. I have used a cylinder cut and faced on the centre lathe and sawn in two for the semi-circular end and glued this to the formed ‘u’ shape. This part is transparent so that the pcb and battery are visible. I thick this will provide a modern look!

3D CAD: Solid Model of my chosen design

Optimum Solutionexploded view

assembled view

Optimum Solution:

Manufacturing

Partial Hearing / Security & Door Bell Indicator

master / re-set switch

(4) Working Drawings

Materials & Production Planning:

Manufacturing Processes Time approx,

1 Manufacture of pcb by chemical bath or CNC - surface machining

Class periods

1

2 Assembly & soldering of pcb / testing 1-2

3 CAD drawings of former/mould design (not a manufacturing process)

3

4 CNC Manufacture of former 1

5 Hand finishing/sanding of former 1-2

6 Vacuum forming of former 1

7 Manufacture of bezel for split mould 1-2

8 Assembly of casing 1

9 Testing the finished product 1

10 Evaluations – write-up!

Materials & Production Planning:

Part: Materials & Processes:1 Base Acrylic / plastic / fabrication

2 Collar Acrylic / plastic / fabrication

3 Top Acrylic / plastic / fabrication

4 Stand Acrylic / plastic / fabrication

5

6

7 pcb Copper clad board

8 Pcb mount

9 LED’s 3 x 5mm LED’s

10 PPP 3 Battery PPP 3 Battery

11 Liquid solvent cement

Environmental Impact:

As I stated earlier the material that I intend using for my housing

design is acrylic plastic. Plastics are made from oil which is a

fossil fuel and unfortunately as the price of oil increases then so

will the cost of plastics. Another disadvantage of this type of

plastics is that acrylic is not biodegradable and therefore plastic

takes many years to disintegrate. However many types of plastics

can be recycled and have alternative uses. Sign makers use

acrylic because it is easily to machine, is lightweight and does not

corrode. Off-cuts can be used for school projects.

An alternative material would have been wood which I had thought

of. Certain types of wood can look well and could easily blend in

with domestic surroundings. Wood can also be recycled, reused

for heating and is biodegradable.

Production Realisation:

Evaluation & critical reflection:

I was quite pleased with the visual appearance of the finished

model and I enjoyed making the product. However I feel I am

now just ready to start all over again and do a better job! My

research materials helped me and the reference materials I

collected inspired the final design. Google images is great for

looking at other ideas / existing products particularly of TV

remote control holders. I also researched mobile phone

holders to get ideas.

The acrylic plastic was quite easy to cut, file, glue and polish

and overall I had no problems using this material.

Fortunately no finishing was required on this material just

polishing the edges on the ‘buff’. The liquid solvent cement

was clean and easy to use in the assembly of the stand.

Evaluation & critical reflection:

My teacher showed me how to use the burette opposite which

applies the liquid solvent cement precisely.

Bending the acrylic was also quite easy I used the hot wire

bending machine for sharp bends and the strip heater for the

larger radii.

I struggled with my time management despite having a plan.

If I was involved in a major project like this again I would plan

my time better!!

In the future the TV may be developed to include some type of

house security indicator providing a signal when an intruder has

enter the property?

Location: Partial Hearing / Security / Door Bell Indicator

TV remote control holder / plus a security alarm and door-bell indicator.

ManufacturingIdea 2:

Alternative Solution: Idea 2:


ManufacturingIdea 3:

Alternative Solution: Idea 3:


Research:

Partial Hearing Door Bell Indicator - House Security!

www.deaf.ie/IDSinfo/Deaftech.htm

www.kimododreams.com/lette/?cat=6

http://www.mitedu.freeserve.co.uk/Circuits/Misc/deafdoorbell.htm

www.homecontrols.com/.../pgrfnbr/503/sesent/00

answers.yahoo.com/question/index?qid=20070528..

http://www.angelfire.com/co3/NCFS/science/dangerousdecibels.html

Analysis, research & investigation - existing products

International Deaf Logo

http://www.deaf.ie/IDSinfo/Deaftech.htm

http://www.kimododreams.com/lette/?cat=6

http://www.mitedu.freeserve.co.uk/Circuits/Misc/deafdoorbell.htm

http://www.homecontrols.com/.../pgrfnbr/503/sesent/00

http://answers.yahoo.com/question/index?qid=20070528135808AAtITvw

http://www.angelfire.com/co3/NCFS/science/dangerousdecibels.html

there is an increased awareness of the importance of safety in the home for both adults and...

Documents

warning devices alarms

personal safety

temperature alarms

research investigation

safe environment slide

importance of safety

alarm system

domestic burglar alarm