Purpose:
The purpose of this project was to show the students how much more deeply one can investigate a topic or object than assumed. For this project we were tasked with disassembling a relatively simple item--we chose an LED flashlight--and researching the components and how they work. We focused on four main areas: energy, information, motion, and materials, and created a presentation and research document.
Project Description
My group's item was an LED flashlight powered by four AAA batteries, each with an output of 1.5 volts. The LED was actually a bar of ten individual LED's, all wired directly in series. The flashlight was made of an outer black plastic shell, with a yellow hook and button. The hook can be used to hang the light for hands-free use. There is also an external magnet on the light, which allows the flashlight to be placed on magnetic surfaces. We attempted to contact the manufacturer, iZoom, but received no response. Thus, all information included in our presentation was gleaned from personal research within our group. After completing a rough draft of our presentation, we peer presented, and collected heaps of helpful critiques. Using these critiques, we were able to better our presentation, as well as condense the information to create a more concise and clear message.
Research:
Our presentation can be viewed here.
Here is a copy of our research document:
Reverse Engineering: Flashlight
Dean Kidder-Buell, Liz King, Ben Klinge, and Austin Marr
Purpose
To discover in depth how an LED flashlight works and to practice reverse engineering methods.
Hypothesis
A circuit is created within the flashlight when the button is pressed. It turns on the light and is powered by the battery within it.
Functional analysis
Structural analysis
The flashlight is made up of a black plastic casing with a yellow button. The casing is closed by 6 metal screws. A clear plastic window protects the LED while allowing the light to be emitted. Within the window, there is a plastic reflector that enhances the light from the LED. When the button is pushed, the circuit is completed, sending the electric current to the LED and emitting its bright light. The resistor prevents too much current from reaching the LED and destroying it.
Material and functional analysis
Manufacturing analysis
This flashlight was manufactured en masse on an assembly line. It was designed in the United States of America, but fabricated in China.
How the Parts Work Together
The components work together to create light. Pushing the button completes the circuit between the batteries and LED and allows the current to reach the LED. The resistor prolongs the life of the light by limiting the amount of current that flows into it. The wires allow the electrical current to travel to the LED. The plastic reflector enhances the reach of the light, the plastic window protects it, and the plastic casing keeps the flashlight together in one, easy-to-use piece.
Works Cited
http://www.cookbrothers.com/product-page.cfm?productno=45222
https://www.jameco.com/Jameco/workshop/circuitnotes/circuit-notes-resistors.html
http://www.madlab.org/electrnx/lesson2.html
https://www.ledsmagazine.com/articles/2004/01/what-is-an-led.html
https://www.explainthatstuff.com/batteries.html
Here is a copy of our research document:
Reverse Engineering: Flashlight
Dean Kidder-Buell, Liz King, Ben Klinge, and Austin Marr
Purpose
To discover in depth how an LED flashlight works and to practice reverse engineering methods.
Hypothesis
A circuit is created within the flashlight when the button is pressed. It turns on the light and is powered by the battery within it.
Functional analysis
- Overview- a button is pressed which completes a circuit, lighting a series of LEDs in the flashlight.
- Power- 4 AAA batteries are wired in series in the back of the light, providing 6 volts to the LEDs. Electrons flow from the negative terminal of the batteries, through the LEDs, and back to the positive terminal of the batteries, where there is an absence of electrons. The electrons are elevated to the negative terminal by ionic reactions within the batteries, and repeat the process.
- LEDs- The conductors in the LEDs are made of aluminum-gallium-arsenide, a material that has no free electrons, because the atoms are perfectly bonded to each other. This material can be doped to have either extra atoms or holes that electrons can go into. An LED contains both of these materials, called N-type and P-type. As electrons move from N to P-type, they drop to a lower orbital, releasing energy in the form of photons.
Structural analysis
The flashlight is made up of a black plastic casing with a yellow button. The casing is closed by 6 metal screws. A clear plastic window protects the LED while allowing the light to be emitted. Within the window, there is a plastic reflector that enhances the light from the LED. When the button is pushed, the circuit is completed, sending the electric current to the LED and emitting its bright light. The resistor prevents too much current from reaching the LED and destroying it.
Material and functional analysis
- Casing
- Polypropylene plastic
- 40 MPa (maximum tensile strength) or 5801.51 PSI
- The purpose of the casing is to protect all of the parts that are inside of the flashlight and it holds everything together.
- Polypropylene plastic
- Clear window
- Polylactic acid plastic (a common clear plastic)
- 20 MPa (maximum tensile strength) or 2900.75 PSI
- Clear piece of plastic that protects LED while allowing light to shine through
- Polylactic acid plastic (a common clear plastic)
- Reflector
- Polyethylene terephthalate plastic
- Magnifies the light by focusing it in in one direction.
- LED
- Light Emitting Diode
- thin layer of semiconductor material, gallium arsenide and gallium phosphide are commonly used
- Aluminum gallium indium phosphide (semiconductor)
- Has no free electrons, atoms perfectly bonded to each other
- Material can be “doped” to have either extra atoms or holes that electrons can flow into
- Polymethyl methacrylate (acrylic)
- allows for energy efficient lighting
- LED contains both of these materials, called N-type and P-type, respectively.
- As electrons move from N to P-type, they drop to a lower orbital, releasing energy in the form of photons.
- LEDs output more lumens than regular incandescent bulbs with less energy input, making them more efficient.
- AAA battery
- Alkaline, steel can
- Held by battery compartment, provides power to the LEDs
- Zinc and Manganese dioxide react in aqueous solution, moving electrons from the positive to the negative terminal
- Positive and negative ions created
- Positive ions flow into electrolyte
- Negative ions flow around outside circuit (blue)
- Separate reaction occurs at positive electrode which completes the circuit
- External Button cover
- SBR Styrene-Butadiene
- Allows user to turn on flashlight from the outside
- Internal Button
- Polypropylene plastic
- When it is pressed, it completes the circuit, which allows the light to turn on.
- Wires (blue and red)
- plastic cover and copper wire
- Transfers electric current from the batteries to the LEDs
- Resistor (3.3kΩ±5%)
- Prevents LEDs from being overloaded, extends lifespan of lights
- Battery forces its electrons through the resistor
- Magnet
- ferromagnetic metals
- Allows flashlight to be hung on magnetic surfaces
- Screws
- metal, nickel alloys
- 345 ksi (tensile strength) or 345000 PSI
- Holds components in place
- metal, nickel alloys
- Hook
- Hard plastic
- Allows flashlight to be hung from many places
- Battery cover
- Polyethylene plastic
- The battery cover serves the same purpose as the casing, but in this case it specifically protects the batteries from the surface
- Battery compartment
- plastic and metal used to connect the battery to the object
- The battery compartment holds the batteries in place and allows the batteries to power the flashlight.
- Each of these materials are fairly cheap, but still durable, which allows for the mass production of the flashlight in order to create a bigger profit for the company.
Manufacturing analysis
This flashlight was manufactured en masse on an assembly line. It was designed in the United States of America, but fabricated in China.
How the Parts Work Together
The components work together to create light. Pushing the button completes the circuit between the batteries and LED and allows the current to reach the LED. The resistor prolongs the life of the light by limiting the amount of current that flows into it. The wires allow the electrical current to travel to the LED. The plastic reflector enhances the reach of the light, the plastic window protects it, and the plastic casing keeps the flashlight together in one, easy-to-use piece.
Works Cited
http://www.cookbrothers.com/product-page.cfm?productno=45222
https://www.jameco.com/Jameco/workshop/circuitnotes/circuit-notes-resistors.html
http://www.madlab.org/electrnx/lesson2.html
https://www.ledsmagazine.com/articles/2004/01/what-is-an-led.html
https://www.explainthatstuff.com/batteries.html
Reflection:
My group worked together fairly well for this project, and we easily finished everything on time. We used a different structure for planning than usual, a GANTT chart, and it helped us to focus on what needed to be done. We also divided the tasks efficiently, so that everyone knew exactly what they were responsible for. The only struggle that we experienced was when one of the group members was sick on the day of the presentation. This meant we all had to present some information that we were not as familiar with, but we were able to pull it off.
This project was very helpful in showing me how much deeper research can go if you take the time to investigate an item. It demonstrated to me what the research and design process should be like for engineering. I learned how to focus on four basic areas: information, energy, materials, and motion. I also found how to research efficiently, finding information through the internet that was not immediately apparent. I believe these skills will be helpful as we begin our capstone projects.
This project was very helpful in showing me how much deeper research can go if you take the time to investigate an item. It demonstrated to me what the research and design process should be like for engineering. I learned how to focus on four basic areas: information, energy, materials, and motion. I also found how to research efficiently, finding information through the internet that was not immediately apparent. I believe these skills will be helpful as we begin our capstone projects.