The document proposes the design of a portable sterilizer machine to safely sterilize hypodermic needles using heat. It notes that over 350,000 Americans regularly use injection drugs and diseases like HIV/AIDS and hepatitis are commonly spread through needle sharing. The proposed sterilizer would heat needles to 100 degrees Celsius, killing diseases like hepatitis B and C (85 degrees) and HIV/AIDS (77 degrees). It outlines requirements for the sterilizer to be small, portable, powered by wall outlets, and cheaply sterilize needles in seconds to encourage use. Trade studies evaluate material options for components like the outer casing, heating element, and inner casings. The proposed design and assembly are shown, along with manufacturing

1. Portable Sterilizer For Hypodermic
Needle
Paul Centeno, Alban Hysa, Nazrul Islam,
Sajeda Marie, Adnan Sakib, Tanoy Sarkar

2. Executive Summary
● According to the American Civil Liberties Union website there is an estimated
350,000 regular injection drug users in America
● The Department of Health states that the most common diseases that are
transferred by sharing needles are HIV/AIDS, Hepatitis B, and Hepatitis C
● Out of the 950,000 HIV/AIDS patients more than a quarter of them contracted
the disease by sharing needles
● It costs a city $160,000 to operate a Needle Exchange Program (NEP) and
$120,000 per year in public health treatments for someone who caught AIDS
by sharing a needle
● Hepatitis B and Hepatitis C are killed 85 degrees Celsius
● AIDS/HIV are killed at 77 degrees Celsius

3. Problem
● Design a machine that can sterilize a needle in high temperatures
safely
● Needle must be inserted in the machine port and reach an optimal
temperature to sterilize
● Machine must be intelligent enough to stop when it reaches optimal
temperature and supply a steady amount of heat
● Power supplied to the machine should be from any wall outlet found in
America
● Portable and easy to transport

4. Requirements
● Machine must be powered by 110 Volts
● Weight of the sterilizer should be around 7 pounds
● Dimensions of the tool should be compact with measurements of
8*4*8 in
● Insertion port must be big enough to accept needle sizes of 2 and 5 ml
with 21 to 25 gauge and length of 12 to 38 mm
● Safety mechanism to stop the machine from overheating or in case of
failure
● Cheap compared to the market tools
● Sterilize needle in seconds

5. Interfaces
● Communication between the sensor and the circuit board
● Needle size and the size of the insertion port
● Wiring and the surrounding material around it

6. Solution Summary
● Came up with 3 possible solutions (steam, heat, chemicals)
● Safety played a huge role in our final decision
● Products similar to it on the market reach temperatures up to of 500 to 800
degrees celsius (to be used by professionals)
● Settled with sterilizer only reaching 100 degrees celsius in order to kill
diseases like Hepatitis B and C(85 degrees celsius) and HIV/Aids(77 degrees
celsius)

7. Solution Summary (contd.)
● Fast heating in order to make sure there is a chance for drug users to actually
use the product
● Making the product as cheap as possible so that drug community could get
their hands on it.
● Other products on market like it cost about 300-400 US dollars
● Investment from either drug users or insurance companies to put in the homes
of the drug users

8. Trade Studies (Outer Casing)
● Outer casing made out of plastic - cheap and light
● Three plastics for consideration: Polycarbonate (PC), Acrylonitrile Butadiene
Styrene (ABS) and High Impact Polystyrene (HIPS)
● Properties include impact strength, maximum continuous use temperature,
density and cost
● Ranking system: 1 (Worst) , 2 (Good), and 3 (Best)

9. Property Polycarbonate (PC)
Acrylonitrile Butadiene Styrene
(ABS) High impact polystyrene (HIPS)
Weight
factor Rating score Rating score Rating score
Maximum
Continuous Use
Temperature
℃ 3 3 9 2 6 1 3
Impact Strength
(Toughness)
ft-lbs/in 3 3 9 2 6 1 3
Density
gram/cc 1 2 2 1 1 3 3
Cost $ 2 2 4 1 2 3 6
Total score 24 15 15
Outer casing (Plastic) - Trade table

10. Trade Study (Ceramic Heating Element)
● This part is the housing item where the needle can be placed inside to reach
100 degrees Celsius
● Three ceramic materials for consideration: Silicon Nitride, Aluminum Nitride
and Silicon Carbide
● The properties to be compared: coefficient of thermal expansion, thermal
conductivity, density, maximum use temperature, cost and volume resistivity

11. Property Silicon Carbide Silicon Nitride Aluminum Nitride
Weight
factor
Rating score Rating score Rating score
Density
gram/cc
1 3 3 1 1 2 2
Maximum Use Temp.
℃
1 3 3 2 2 1 1
Coefficient of
Thermal Expansion
(10–6
/°C)
2 2 4 3 6 1 2
Cost $ 3 2 6 2 6 2 6
Thermal conductivity
(W/m•°K)
3 2 6 1 3 3 9
Volume resistivity
(ohm•cm)
2 3 6 1 2 1 2
Total score 28 20 22
Ceramic heating element - trade table

12. Trade Study (Inner Casings)
● On the outside of heating element, material needs to be placed to hold it in
place and divide it from rest of inside
● Material must be able to withstand high heat, some physical stress, and be
malleable while not being too expensive
● Choice between aluminum, stainless steel and cast iron

13. Property Aluminum Stainless Steel Cast Iron
Weight
factor
Rating score Rating score Rating score
Tensile Strength 2 2 4 3 6 3 6
Coefficient of
Thermal Expansion
(10–6
/°C)
3 2 6 3 9 3 9
Melting Point 3 3 9 3 9 3 9
Malleability 3 3 9 3 9 1 3
Cost 3 1 3 2 6 3 9
Total score 22 39 36
Inner Casings - trade table

14. Solid Model
Heating Element
Material: Silicon Carbide
This section of the Portable Sterilizer is
essentially
the core of the project.
The first feature is the flange which
allows the installation to the steel casing.
The Next feature on the ceramic element
are the grooves which allow the
placement of the windings.
The grooves are 0.68 mm in depth which
allow the wire windings to sit fixed.

15. Steel Housing
Material : Stainless Steel
Heating Element will be secured to this housing
using ceramic cement.
Two holes of 6.5mm diameter are located on the
cylindrical section of the housing to allow the wires
to enter to the element. The distance between the
holes is 134 mm.
.

16. Casing and Caps
Material : Stainless Steel
The pattern of the holes are shown in
the top and bottom of the casing help
dissipate the heat released from the
center.
The center hole is used to wire the
PCB to the heating element.
There are two casing caps that cover
up the casing, this is used for safety to
prevent any contact to the hottests
parts of the machine

17. Bottom cover plate
Material: Stainless Steel
The bottom cover plate is the section that
assembles all the pieces together. The total
dimensions for the plate is 8x4 in.
The left side of the plate is the section
where the heating element and its casing
sit. The right side has 4 extruding cylinders
to allow for the installation of the PCB.

18. Component Cover
The cover is the same dimensions as the bottom cover plate. This is made of
Polycarbonate, with the hole on the top face for the needle, and a slit at the center to
allow for the separation plate to slide into.

19. Assembly

20. Insulation
Ceramic Fiber Insulation designed to insulate high
temperature elements. Max insulation temperature
is 2300 F.
Ceramic Fiber Tape suitable for high temperature
applications up to 2300°F.

21. Assembly

22. PCB
The printed circuit board (PCB) mechanically supports and electrically connects
electronic components by using conductive tracks on a non-conductive material.
Our system uses the voltage of 115v and by induction generates heat on the syringe.
Using Diptrace we created a schematic for the circuit including the PCB layout.

23. Manufacturing (Cost)
● We aimed at a cost reduction of about 50%
● Plan to make it as affordable as possible
for target demographic
● Cost analysis of market products made
found final price to be ~$150

24. Manufacturing (Product Breakdown)
● Purchase- Screws and Switch
● Manufacturing- Casing caps, Bottom Cover Plate, Panel
● 3D Printing- Component Case
● Alternative Methods- Casing, Steel Housing, Heating Element

25. Manufacturing (Methods)

26. Manufacturing (3D Printing)
● 3D printing is a creative and
affordable method of producing
components
● Many different materials can be
used for 3D printing, such as
ABS plastic, PLA, polyamide
(nylon), polycarbonate etc.
● Size reduction needed to fit
printer boundaries.

27. PLANS FOR TESTING
The backlog: A list of prioritized requirements
Iterations (or sprints) in hardware/software development
Risk management
Cross-functional teams
Customer input

28. ITERATION 1
1. Acquire needles
2. Collect initial temperature of the needle
3. Start the device and run it till the device reaches optimal temperature, 100C
4. Inject the needle in the device
5. Collect temperature data during the process.
6. Remove the needle from the device.
7. Collect final temperature of the needle
8. Use data to compare the final temperature to observe what types of bacteria had
been eliminated and what had not.

29. COLLECTING TEMPERATURE
A pyrometer is a type of remote-sensing thermometer used
to measure the temperature of distant objects.
In the modern usage, it is a device that from a distance
determines the temperature of a surface from the amount of
the thermal radiation it emits, a process known as
pyrometry and sometimes radiometry.
This is the best way to find the temperature of a surface.

30. References
https://www.aclu.org/fact-sheet/needle-exchange-programs-promote-public-safety#1
https://health.ri.gov/disease/prevention/about/notsharingneedles/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608191/
https://www.ncbi.nlm.nih.gov/pubmed/1374578
https://www.jondon.com/how-to/technical-tips/communicable-diseases/hepatitis-b-and-c.html

31. Questions?