1. Our team Chemical Device
·
Team Chemical Device: Automated CO Monitoring &
Ventilation System
·
Background:
Around 2.6 billion
people still cook using solid fuels (such as wood, crop wastes, charcoal, coal
and dung) and kerosene in open fires and inefficient stoves. Most of these
people are poor and live in low- and middle-income countries. These cooking
practices are inefficient and use fuels and technologies that produce high
levels of household air pollution with a range of health-damaging pollutants,
including small soot particles that penetrate deep into the lungs. In poorly
ventilated dwellings, indoor smoke can be 100 times higher than acceptable
levels for fine particles. Household air pollution (HAP), which results from
incomplete combustion of the solid fuels. à
Incomplete Combustion chemical equation: Fuel + O2 -> CO + Stack gases. 7.5
million people die from HAP annually most of them originating from lower income
countries.
·
What is currently being done to help:
For example: United Nations and
World Health Organization (WHO)
·
Advocacy and Educational Efforts
Working to integrate guidance and
resources for supporting clean household energy into global health initiatives
and decision-support tools, such as the Global Action Plan for Pneumonia and
Diarrheal Disease (GAPPD).
Advocacy can help increase
awareness of the importance of providing and scaling up of cleaner household
energy as a core preventive public health measure.
·
Providing Technical Support to health-promoting
household fuels and technologies
·
Challenge despite efforts:
1) Takes
a long time for solution to be developed and implemented in the process as such
organizations are working towards large-scaled, long-term solutions. But in the
meanwhile, it means more deaths every day.
2) Changing
rural people’s attitude and effectiveness of solution:
Programs to introduce clean
cookstoves cannot simply assume that these so-called improved stoves will be
accepted by the rural household or that they will benefit health. The open
fires these rural people use to cook has deep rooted connections to their
cultures and hence carries the risk that implementation of greener cooking
methods will not improve health since the rural people might not be open to change.
3) Affordability
Even if these organizations do
implement greener alternatives, the daunting task ahead is to ensure it is affordable
and scalable to hundreds of millions of households who already face financial
worries.
Resources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3672215/
https://borgenproject.org/cooking-fuel-in-developing-countries/
è Hence, this explains why our role is so
important.
·
THE ISSUE WE WANT TO SOLVE:
Solid
fuel use is closely linked to poverty and clean cooking technologies must be
affordable and desirable to families with limited and insecure incomes.
·
PROBLEM STATEMENT:
What
sustainable and/or affordable solution can we provide to prevent health
consequences arising from ineffective cooking methods i.e. household air
pollution to lower-income rural families whilst allowing them to hold onto
their beliefs?
·
How our prototype solves the Issue?
- Provides
a short term, affordable solution (refer to our
design specification table, total cost of prototype < $150, cheaper compared
to initiatives governments/organizations roll out which costs millions of
dollars and also take long to implement)
- Complete
autonomy of use for people (rural people won’t feel
restricted that they have to follow rules when using our prototype, unlike when
policies are implemented.)
- Sense
of independence and freedom for users
- A
catalyst to drive change
(rural
people might still want to use fuel to cook because of ties it has to their culture
so we can’t expect their behavior to change overnight hence the CO monitoring
and ventilation system i.e. our prototype, complements their current behaviors
and acts as a catalyst for change to cleaner sources of fuel à when they see how many times the ventilation had been triggered, we
hope they become more aware of how unsafe their current cooking method is and
be open to change)
·
EFFECTIVE
(It can effectively detect unsafe levels of CO, reflect
it on the LCD screen for the user to see and also provides a solution i.e.,
ventilation to return back environment to safety for user.)
·
HAND SKETCH OF FINAL CHEMICAL DEVICE:
2. Team Planning, allocation, and execution
Team Members:
Serena – Chief Executive Officer
(CEO)/Leader
Kenny – Chief Financial Officer
Kai Rong – Chief Operating Officer
Jerome – Chief Safety Officer
Finalized
BOM table:
Finalized Gantt Chart:
Planned:
Actual:
Changes are only in the Manufacturing of
prototype and Final Check Stages (highlighted in yellow 4.5 – 5.4)
Task Allocation
·
Serena and Jerome are in charge of CAD fusion while Kai
Rong and Kenny are in charge of the Arduino Programming
·
The team then comes together to 3D print, laser cut
then assemble and prototype testing
3. Design and Build Process
Design
Process:
·
Evolution of Idea to Final Prototype (Using Hand
Sketches & CAD Screenshots)
1.
Our Initial Idea
(Brainstorming & Ideation)
In the Figure below, the long
rectangular box was supposed to be a casing for the electronics i.e. Arduino
Board, Breadboard wiring, sensor (for monitoring of CO), LCD display etc,
whereby we would hotwire and connect a portable fan we would buy from external
sources e.g. Lazada to this electronic casing for the ventilation aspect of the
prototype.
However, after going through the idea refinement processes
such as TRIZ, we realized we had to refine our initial idea as it was not
effective.
2
.
Our Refined Idea (Idea
Refinement Processes)
In Figure 4, our initial idea, we
realized that our chemical device was placed in the surroundings itself this
was ineffective because it means that even after the fan blows the excess CO in
order to restore the CO level to be safe, this blown CO would not be redirected
elsewhere because it would just be blown back into the same surrounding air
i.e. we had not reduced the level of CO in the surroundings after all.
Hence, after going through TRIZ,
we came to realize that to refine our idea further, we had to change the local
quality of the air. (See Figure 5: Conclusions from TRIZ).
Hence, in order to change the local
quality of the air, we knew it meant the excess CO had to be directed out of
the surroundings. Hence we decided that our chemical produce had to be
placed in an enclosed space like a vent whereby it should have an inlet and
outlet opening for the air to enter and exit. This is so
that when
CO detected by the sensor exceeds the limit the fan blows out the excess CO and
as the outlet hole is the only exit route, it would be directed out and escape
externally , helping
to change the local air quality in the box to be of safe levels of CO.
3.
Adjusted Concept
(Planning Phase + Consideration of BOM)
As we entered the Planning phase whereby we discussed
who would take charge of which components of the device and eventually build
that as well as planning for our budget in our Bill of Materials (BOM), we
realized that a way to further reduce the cost in our BOM was to not buy a
portable fan from Lazada but instead make use of the resources and skills we
had i.e. Arduino Program a DC motor with an attached fan propeller to rotate as
a replacement to the fan. This saved us approximately $30 and also the fact
that we didn’t have to lag behind our progress later on due to waiting on
delivery time also made us a high performing team. Another adjustment we made was
the design for the electronics housing case. Initially the design in the
earlier 2 sketches showed the electronics housing unit to be long but short in
terms of height because we thought we could bend the wires and save
material. However after measuring the
dimensions as we prepared to enter the building stage, we realized we
couldn’t bend the wires and hence we had to build a smaller box inside of the
larger box (vent) to act as the electronics housing.
4) Improved Concept (After feedback
from Dr Noel)
At
this point, we were confident of our Adjusted Concept and hence had already
dived into the Computer Aided Design (via Fusion) part. However, when we had a
Microsoft Teams consultation with Dr Noel, he gave us some feedback (in the paraphrased
quotes) which prompted us to change our entire design i.e.
·
“Think about the fact that your device is going to be
used as a kitchen fumehood. How should the airflow be in that case?”
·
“Would the
current orientation provide sufficient negative suction for the airflow in and
out?”
·
“If you place your DC motor this way i.e. simply rested
on a stand, wouldn’t it vibrate and wouldn’t that affect the performance of
ventilation?”
·
“I currently cant visualize it to be a fumehood, how
will you change your design to replicate one? Look at the resources in DCHE
blog”
Hence,
we improved our design by firstly changing the orientation to be vertical
I.e. the airflow inlet and outlet would be vertical now instead of horizontal
earlier. This was because in order for our prototype to solve the issue we
wanted to, it would be used as an affordable kitchen fumehood hence, the air
from the cooking would rise and travel upwards vertically. This also meant that
the fan which provides ventilation to blow out excess CO would now be placed
vertically facing upwards. This was to ensure we could create negative
suction pressure for the air to be drawn in and later CO exit out. Hence to
provide sufficient inlet air flow as well as for the general appeal to look
like a kitchen fumehood, we created a bottom hood like structure. To hold in
place the fan connected to the DC motor to ensure the ventilation provided is
efficient, we also decided to make a DC motor casing which would also act as
a stand to allow the fan to prop out of the electronic casing as well. The
air would enter from the ghood vertically upwards and exit through the top hole
of the cylindrical pipe. There is a gap between the inner and outer boxes as
the inner box is completely sealed with just a hole for the fan to be
protruding out of it but still in the outer box.
5) Final Prototype (with Mechanism)
We then decided to add a Lever Mechanism which would be operated using a servo motor. The purpose of this is to make the air flow exiting the device to be automated. For our earlier Improved Product, the plan was for the cylindrical pipe to always be opened however we realized this meant that there could be clean air lost. And for already poorly ventilated spaces where our target audience lives this could be more harm than good. Hence to prevent this it meant that our air outlet pathway should only be open when it needs to i.e. when CO levels are unsafe. Hence to make this automated, there will be a cap on the cylindrical pipe which would be connected by a lever. When CO levels are unsafe and the fan turns on, the servo would also turn on to push the lever and open the cap as the servo turns 180 degrees angle.
Building
Process:
Measuring of
dimensions to double check and make changes in our parametrically design fusion
files before laser cutting or 3D printing straight away.
Jerome and
Serena designing the parts in Fusion 360
The team then
came together and went to fablab to laser cut our parts which includes the inner
box and the outer box
Hero shot of
laser cut parts
Sanding of laser
cut sides – to ensure sides are smooth such that they will have better adhesive
when gluing them together
Cardboard
prototying where the main skill used was scoring to form the cylinder shape
tube as well as to make a box shape for the servo to sit in
Kai Rong and
Kenny programming the Arduino for our product and was successful to do so
including for the servo
Hero Shot of
Arduino Programming
Code for our product
which uses the IF Else function to program such that when CO level is more than
9pmm, the message will display saying CO-unsafe Fan On and the fan would also
be switched on
The team came
together to 3D print parts like L-brace to support the inner box and the
Dc-motor case
Hero Shot of 3D
printed parts
The team then
assembled our product using acrylic glue from W319 (chloroform)
Hero shot of
final product
Allocated
work:
Part 1. Design and Build of Outer Box (done by Serena).
https://cp5070-2021-2b04-group2-serena.blogspot.com/
Part 2.
Design and Build of DC Motor
Casing (done by Serena).
https://cp5070-2021-2b04-group2-serena.blogspot.com/
Part 3. Design and Build of Inner Box (done by Jerome).
For the inner
box, it consists of 6 sides, 3 of which has to be paid more attention to as
there are modifications to be made to them.
LCD side – Screw holes are accurately measured out and extra
holes are cut to ensure the lcd is completely flushed with the acrylic
Measurements: 110mm x 130mm
Distance between corner of lcd and screw hole – 0.4mm
(bottom side), 0.3mm (top side)
Distance between screw holes – 7.5mm (longer side), 3.1mm
(shorter side)
Sensor side (bottom side of box) – Screw holes are
accurately measure out
Measurements: 130mm x 150mm
Distance between corner of CO sensor and screw hole – 0.8mm
(bottom side), 1.8mm (top side)
Distance between screw holes – 2.8mm (longer side), 1.6mm
(shorter side)
Top side – hole is made bigger in size to ensure that the
fan can fit comfortably and is able to spin without any obstructions
Measurements: 130mm x 150mm
Hole diameter: 80mm
The rest of the
sides do not need special modifications and are just normal slates of acrylic.
Measurements: 110mm
x 150mm
Part 4. Design and Build of L brace (done by Jerome).
For the L brace the measurements I used are shown
Part 5. Programming of DC motor, Sensor
and lcd (done by Kai Rong & Kenny).
Kenny: https://cp5070-2021-2b04-group2-kenny.blogspot.com/
Kai Rong: https://cp5070-2021-2b04--group2-kairong.blogspot.com/
Part 6. Programming of Servo Motor &
Build of Mechanism (done by Kai Rong).
https://cp5070-2021-2b04--group2-kairong.blogspot.com/
Part 7: Integration of all parts and electronics (done by Jerome)
Documentation
for integration.
For integration of all the parts, we need to insert all the files into a single file and to do that, save all different files. To access the files, open an empty file (insert pic)
and click on the left icon which shows all the saved files (insert pic)
To insert the
file you want, right click on the file and there will be an insert option
available (insert pic).
Make adjustments
needed and repeat for other files (insert pic for final file)
Interconnection of parts
Air will travel upwards towards the vent of the chemical device from the bottom of the chemical device when someone is cooking, and fumes are produced from the solid fuel.
CO sensor is programmed so that when it senses a certain CO level it will start the D.C moto and the fan will start to spin and since there is negative air pressure, the air is sucked towards the fan from the bottom side and is blown out to the top side.
In the meantime, the LCD will also display the amount of CO present so that users are aware of the amount and will know when the process will stop.
The servo moto will also start to move the cover of the tube to allow air flow out of the device.
The unwanted CO will be blown through the tube and away from the direction of the user minimizing the amount of CO inhaled
When the CO is blown out the sensor will sense that the CO is at an acceptable level and the servo moto is programmed to close the opening of the tube to ensure nothing could drop into or enter the chemical device that could potentially damage the electronics or the fan.
If you can tell, everything starts with the CO sensor sensing CO beyond the acceptable level and the chemical device will start to operate coherently and smoothly.
Part 8: Assembling of FINAL Prototype (done
by EVERYONE) Links of EVERYONE’s Blog
Kenny: https://cp5070-2021-2b04-group2-kenny.blogspot.com/
Kai Rong: https://cp5070-2021-2b04--group2-kairong.blogspot.com/
Serena: https://cp5070-2021-2b04-group2-serena.blogspot.com/
Part
9: Prototype Testing, taking
of video (done by Kai Rong) Link to Kai Rong’s blog
https://cp5070-2021-2b04--group2-kairong.blogspot.com/
Part 10: Presentation
Link to presentation file
Link
to vid of product
https://drive.google.com/file/d/14_posj2nX8yFT_2yQBLpnF8LjScURh5G/view?usp=sharing
4.
Problems and
solutions
Problems on Programming
-
Programming in Tinkercad Simulation works but was not
able to be implemented (LCD display does not light up)
-
Solution: Found a video that showcase how to connect CO
sensor and LCD display to Arduino
-
Coding: When the fan is switched on, LCD display turns
off (LCD should be on at all time to show CO reading); When CO level is high
>9ppm, fan switches on and off every few seconds (Fan should be on
continuously when reading of CO is high)
-
Solution: Used a mix of programmable button (IF…ELSE
function) and servo (poswrite180o) codes.
5.
Project Design Files
as downloadable files
https://drive.google.com/file/d/16US4Ee6Yv6QzoO5Eqw8VK0YuUZaBvMfb/view?usp=sharing
Inner box^
https://drive.google.com/file/d/1dVnbvC02QMagQYt3TKABhVewsc-Rj1vu/view?usp=sharing
LCD Fusion^
https://drive.google.com/file/d/1rxrNicnFk8TmBCd0i6dgwn8vhhc5QSP_/view?usp=sharing
LCD dxf^
https://drive.google.com/file/d/1lM3QLU2YQ8SOM61EEU-sjctBiXybhDj5/view?usp=sharing
Top side and blank sides fusion^
https://drive.google.com/file/d/1dUC-bmIWiVGjZPOLyV12jLwuNTIgjrlf/view?usp=sharing
Top side and blank sides dxf^
https://drive.google.com/file/d/1VcCbOx9nch3ucIoMhNGhccHpeng7kutX/view?usp=sharing
Sensor side fusion^
https://drive.google.com/file/d/1VcCbOx9nch3ucIoMhNGhccHpeng7kutX/view?usp=sharing
Sensor side dxf^
https://drive.google.com/file/d/17riFTkPHhfT9ir7lr11oGAv0wVEisQ4o/view?usp=sharing
Outer box fusion^
https://drive.google.com/file/d/17riFTkPHhfT9ir7lr11oGAv0wVEisQ4o/view?usp=sharing
Outer box dxf^
https://drive.google.com/file/d/1aOkVyXKqdk6uYy01ykPr-1dFtQiNcY2O/view?usp=sharing
D.C moto case fusion^
https://drive.google.com/file/d/1BOH6P994_IGjI2LtmbPETqKZ--EcYEMr/view?usp=sharing
D.C moto case stl^
https://drive.google.com/file/d/1g_9KzJFfzKkLQkiqxXrK9FlGLSbBFkgX/view?usp=sharing
D.C moto case Ultimaker^
https://drive.google.com/file/d/1MDV__H6hzEsr-vI1s9w-zVgIgiBYcPlr/view?usp=sharing
L brace fusion^
https://drive.google.com/file/d/1bpRbnSHUBbb82xOFN4qs1P7jzukDxXdA/view?usp=sharing
L brace Ultimaker^
https://drive.google.com/file/d/1cXgpK-Qe2hwZ73Zxi-eVw1etVy9GImwJ/view?usp=sharing
CO sensor code^
https://drive.google.com/file/d/16KfV-mVFujIM680jdprBxRwNdpd7eDDX/view?usp=sharing
Servo code^
https://drive.google.com/drive/folders/1nWQTAlFILeUSal-LZAw4vsjPTBo3FxOS?usp=sharing
MQ2 library^
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