Firstly I would like to thank my personal tutor Dr Steve Summerskill for his time, continued encouragement, support and guidance throughout this project.
I would like to express my gratitude towards the module leader Dr Richard Bibb for running the FYDP module smoothly and having prepared a range of useful documents to aid project work.
Thanks are also due to electronics technician Mazin Farjo and Dr Tom Page for their expertise and patience whilst working on my electronics.
I am also indebted to my parents for providing me with the means to study as well as funding my final year project.
Introduction Review of the project brief Review of design development Summary of prototyping Review of user evaluations and findings Design for manufacture Resultant design changes Final design proposal Appendix
LB = Logbook
DFM = Design for manufacture
p = Page/s
Various forms of air pollution are causing ambient air quality to deteriorate worldwide. This problem is especially prevalent within urban environments and more so in developing countries. Out of all the cities reporting on air quality only 12% of people reside in those that meet WHO guidelines for safe levels. About half of the urban population monitored is exposed to air pollution 2.5 times higher than recommendations. Inevitably this is a major environmental risk to health, for example, in 2012 air pollution was estimated to cause 3.7 million premature deaths worldwide. Research indicates that cyclists are at higher risk of related health implications due to elevated levels of exposure to and intake of pollutants. With very few current solutions, many of which being an inconvenience to cyclists, an opportunity to create a new product had been identified.
User Needs Users need to be able to cycle within urban environments without having an elevated risk of health implications resulting from exposure to and intake of ambient air pollution. Doing so should not impede upon their cycling experience. User Description Users are health conscious urban cyclists; this encompasses a global range of city dwelling cyclists of any age or gender that cycle on a regular basis. They are aware of and feel vulnerable to ambient air pollution wishing to reduce their intake as best possible. They value their health and would be willing to invest in products to reduce the risk of related health conditions. There are millions of global users residing in both developed and developing countries. Proposal A bicycle mounted respirator to provide urban cyclists with clean, breathable air that is comfortable to use and doesn’t tax the lungs during times of exertion. The product will provide an indication of when it should be used and will utilise a front facing LED bicycle light.
Although not fully resolved, by the end of the stage one submission a clear design direction had been adopted. Along with feedback, the initial design provided insight into previously unforeseen issues as well as an indication of the necessary developments required in order to progress. Despite this, it remained a foundation for the final prototype with component positioning and layout remaining very similar, if not the same. At this stage there was a lack of definition with regards to the face mask and breathing tube however these would be addressed later (LB4, p1-17).
Key issues with the initial design:
Problematic lid – not enough space to have a functional hinge. Too few buttons to cater for the proposed functionality. Not well suited for prototyping.
Following evaluation of the previous concept, instead of continued development the decision was made to utilise a complete redesign (LB3, p80-
91+LB4, p38-63). This was an opportunity to rectify previous shortfalls and implement key developments simultaneously. During the redesign additional functionality had been included, for instance, an automatic bike light controlled via an LDR. Above you can see the first iteration.
The first iteration re-sited the intake vents from the lower rear of the device to the lid. This presented the chance to add further aesthetic detailing as well as an interchangeable, modular part. The hood had been designed to prevent rainwater from entering the device whilst allowing air to pass through gaps in the side. However, this was not convincing enough prompting further development
(LB4, p59-60).
New ideas were implemented in order to decrease chances of rain entering. For example, making use of gravity, new lid panels included cavities and internal slopes (LB4, p 65-66).
Efforts to design panels that would serve as an air intake and refuse to draw in rainwater proved very difficult. Given this, the logical approach was to locate the vents on the underside. Here it would be very difficult for any rainwater to enter even when the fan is active (LB4, p67).
The mounting bracket for the device also underwent development. The initial form was as above, however, this didn’t complement the rest of the product and was later adapted to have a smoother profile that would also hide the fixings (LB5, p2-7).
Initially holes were added in the ribbing in order to try and save on prototyping costs and for the same reason the battery holder was going to be laser cut. However, due to the method selected this was no longer necessary. Holes were removed and extra ribbing/bosses added where needed. A new battery holder was also designed to better support the battery (LB4, p68-69).
With the vents now on the underside this was a prime opportunity to reposition the dust sensor for maximum accuracy (LB4, p68).
The breathing tube connector had been developed alongside a counterpart docking station in which it plugs into when the device is not in use. This would make it easier to store the tube (LB4, p83-87). Finger grips were added to the connector to give the user more purchase when removing from a magnet connection (LB5, p1, 8-9).
Later the first of a wide range of potential modular attachments for the face mask were designed. These included an aesthetic insert for user customisation and miniature filter holder so the mask could be used as a standalone product
(LB5, p46-48).
Low fidelity cardboard modelling was used to create a number of low cost prototypes quickly and efficiently. These physical models would allow for a better understanding of the space required to mount the device (LB2, p50-57).
Able to be tested to destruction, these prototypes were torn apart to and used to trial the potential component positions that had been identified earlier. This activity highlighted the fact that the device could afford to be a lot smaller than originally planned (LB2, p82-85).
All prototypes produced were subjected to user testing and evaluation so that insights could be captured and any unexpected problems illustrated. Additional parts had been added to the prototype such as a breathing tube and facemask. This helped to form a more realistic scenario in which to test each iteration (LB2, p50-57).
New card prototypes were created in order to further evaluate component positioning as well as prospective shapes and sizes for the device (LB3, p36-41).
Electronics prototyping was a continual process much of which had taken place either on or using breadboard. Several prototypes had been produced, each time demonstrating a different element of the devices proposed functionality. These were particularly useful to ensure no errors during prototyping (LB4, p22-32).
Prototypes had developed in a linear fashion until all components
had
been
consolidated
onto
one
breadboard. This allowed all
functionality
to
be
demonstrated whilst also proving that manufacture of circuit board was viable
(LB4, p33 + LB5, p37-39
Eventually a single prototype had been produced that served to demonstrate both the aesthetic and functional qualities of the product.
Please go to Folio 2 to see the CAD models produced used to manufacture this prototype. This also illustrates how the main components are assembled.
Folio 3 contains photos of the finished prototype.
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In order to evaluate the success of the design, using the prototype that had been created, user testing was conducted. The participants were provided with a scenario and around half provided with a brief explanation of the product and its functionality. Scenario: It is early morning, you live in a large city and you are getting ready to cycle to work. It is dark outside and you prepare both your bicycle and mounted
�
respirator prior to setting off. With many others joining the morning
commute you end up cycling through slow vehicle traffic. Upon arrival at the bike park you then walk to work a busy, slow moving road.
Within the scenario participants were required to carry out specific tasks relating to the use of the product. Their actions were recorded with photographs taken for further analysis, afterwards direct user feedback was gathered. The results can be seen within the User Testing Binder.
Conducting user testing had enabled the collection of useful insights and had allowed some problems with the design to be identified. The main problems or strengths of the design have been documented within this report (LB5,
p56-85).
The first issue experienced was that without any prior instruction it was not immediately obvious as to how to open and close the lid to the product. Unexpectedly, a few participants had held the lip of the lid when opening. Although acceptable this was not as had been intended. When closing some had difficulty aligning the front push fits which would result in the lid becoming jammed.
A minor problem that had been identified was locating the battery into the holder as intended. Some participants tried to insert the battery in a puzzle like manner attempting different positions and a couple inserted it upside down. Although this wouldn’t affect performance it shows that it the intended position could be made clearer.
Participants didn’t seem to have any issues when connecting the breathing tube to the mask and many commented that they liked the tactile feedback of the magnet fit slotting into place. This is something that could potentially be utilised elsewhere within the design such as on the rear of the product where the breathing tube exits. However, when attaching the tube to a worn mask it proved slightly more difficult.
As demonstrated here when the mask is worn there is no clear view of the docking insert for the end of the hose making it more difficult to fit.
Difficulty fitting attachments to the mask when worn soon became the most common task in which users struggled to complete quickly and easily. This was especially prevalent when users tried to fit the mini filter attachment to the face mask. Many had to use both hands to locate the attachment correctly.
After aligning the parts virtually all participants were able to fit the mini filter unassisted with little to no verbal guidance.
Most users experienced the issue with a varying degree of difficulty when completing the task.
On one occasion, due to the entire docking insert being made of metal, this had resulted this had in a poorly located mini filter rendering the mask ineffective provided the user was unaware.
Most significant issues discovered during testing were the following: Without prior instruction it is not immediately obvious as to how users are supposed to interact with the lid, many hesitated while they tried to figure out how to remove the lid. When replacing the lid many participants failed to locate the two front push fits which resulted in the lid failing to close properly and becoming jammed in place. It proved quite difficult for users to locate the various mask attachments into the corresponding docking insert when the mask was worn. Many had to use their hands to locate the insert.
Minor issues included the following: The intended positioning of the battery was not clear for users. This meant that on occasion the wire was left loose or the battery was inserted upside down. The mask straps proved an inconvenience for those with long hair and glasses as they have to be stretched over the users head.
(LB5, p86)
Potential design solutions to the problems identified include the following: Adding grips or finger grooves to the lid to highlight intended hand placement and offer an indication of how the lid moves. New location features used to both guide and secure the lid in place. This could be a continuous lip that follows the inner contour of the lid. A more intuitive docking insert for the mask that utilises additional tactile and location features that provide physical cues to the user. Use of a cordless battery either internal or as part of the outer casing having a distinct shape, both having to be inserted in a particular way. New wrap around straps that use Velcro so that users do not need to stretch elasticated bands over their head.
(LB5, p87)
Who is the buyer? The product has been designed for the cycling market and would be sold to retailers that are well positioned in this area. This includes a wide range of retailers that operate through online services as well as in stores. It could also be sold directly to users via the products own website.
What is the market? A number of limiting factors and demographics can be analysed in order to help determine the size, value and geography of the potential market. These include the following: Severity of the air quality problem GDP per capita ($) Urban population size Bicycle culture and usage
Size
Value
Geography
843,443 people ÂŁ210,852,315 Europe (Possible expansion into Far East)
(DFM, p3-12)
Process selection All of the parts had been designed to be mass manufactured via injection moulding, the process had been chosen using a selection matrix (DFM, p14-17). For a detailed analysis on the parts created please see Folio 4.
Costing For a breakdown on the entire manufacture costing please refer to the DFM report pages 18- 25 and Folio 4.
Due to the product being designed for injection moulding a number of changes had to be made in order make it suitable for manufacture. The casing was split up in to more parts to allow the design to be formed.
As many undercuts were removed from the model as possible with a number of location features to help fix the casing parts together.
The lid still makes use of push fits however the type and direction had changed based upon user feedback. An additional brace is used to secure the output of the fan.
Holes were added for fixings to locate into and a new magnet connector was designed to allow for complete adjustability of the breathing tube.
The lid panels were made removable so that user’s wold be able to customise their product further.
Other parts had to be adjusted slightly to both allow for manufacture and appropriate assembly. For example, the tabs in the lens cover were removed to prevent undercuts.
These images display the new push fit mechanism for the lid. The lid now has a simple tab at the top which has to be located prior to insertion as well as four push fit pins which locate into corresponding holes.
Munda™ a powered respirator designed to protect the urban cyclist from the harmful pollutants they are exposed to.
Having taken Munda™ from ideation through to a functional and aesthetic prototype, improvements have been identified and there are still many developments that are required before it could truly be considered a viable product.
For example, a final design proposal would require many changes to be implemented, some of which include the following: A method of keeping the lid closed while the device is left unattended. A method of keeping Munda™ attached to the bicycle without risk of theft. Seals on all joining casing parts to keep internal components protected.
These are just a few instances, to see the final evaluation of Munda™ please go to Folio 4.