The Creation of an LDR
Jahshiek Wade, Mohammad Ashiqul Islam, Angel Morel, Anthony Del Rosario
Department of English, The City College of New York
Engl 21007: Writing for Engineering
Professor Sara Jacobson
April, 26 2021
Society has grown, and as a result, people have become more dependent on the various innovations that impact the comfort and productivity of their daily lives. One of these innovations is the electrical grid. Almost everything humans need daily necessitates from the continued supply of electricity. For this engineering proposal students are asked to identify a void or need for a specific engineering innovation for which they will use their knowledge acquired through research to design and produce something capable of satisfying said need. This proposal revolves around a device that produces light when exposed to darkness also known as a Light Dependant Resistor(LDR).
An LDR provides light in dark areas. People who have vision trouble will find this device to be helpful, considering that they may not be able to locate switches efficiently in low light situations. The night activated Light Emitting Diodes (LED) will produce light when it becomes dark around it. The LDR serves the visually impared best, but is not exclusive to their use, ergo people who are just instinctively scared of the dark will be reassured. The problem is in dark areas the creation of an LDR to provide light in dark areas. The creation and explanation of the LDR will be used as a representation of the knowledge acquired from Technical writing. Within his proposal night activated LED/LDR is used interchangeably.
- Proposed Idea
The world is connected by way of electricity and is familiar with the use of LEDs to provide light as a temporary replacement for natural light. It is quite useful but not widely demanded on an individual scale, ergo the proposal addresses something the group would use, and then would attempt to apply it to other small groups of people who would apply it to their daily lives. Our proposal introduces people to technology that isn’t widely used but has power to control surroundings and be efficient in darker environments whether its a naturally dark area or a result of external incidents, such as power outages. Our group is trying to make a dark activated light dependent resistor (LDR).
The question may arise: What is so innovative/important about an automatic night light? This is because the LDR is suited to help those who may not be able to help themselves or at times don’t want to. An LDR is simply a subset of the larger automatic light inventions. A normal LED can only be activated when one turns it ON/OFF, it doesn’t have the power to adjust itself to the varying levels of light. On the other hand, a light dependent resistor or LDR does exactly what people need. It’s a great help for the visually impaired or for people who are just afraid of dark. If we compare it to other things like a flashlight or just regular LEDs, they’re of no use to someone who’s visually impaired or people lacking a sense of security. In addition, the use of an LDR prevents the further usage of major lights, because the LDR would be proportional to the room and would provide sufficient light to allow people to avoid obstacles, and map out the room.
There is a fact that a standard artificial light produces more light pollution, meaning the amount of light produced by one standard light bulb produces more luminescence which affects wildlife and us. An article from (Goodbulb, 2019) says that “Light pollution is among the most chronic environmental perturbations on Earth. While true that light pollution may not be as toxic as, say, a chemical spill, it is reported that this is an issue that affects an estimated 99% of humans and animals across North America and Europe. ” For example, a negative effect is that it interferes with the sleep schedule of many living creatures. With a light dependent resistor, the time for which the light would be on can be shortened and modified depending on the amount of lux needed to perform various activities. Based on the tinkercad diagram (image 1.4), it is evident that the LDR can stay in use with the help of an external power source. On a microscale, rechargeable batteries would work well but it is also dependent on the amount of light being produced and for how long. On a slightly larger scale a solar powered generator could act as a power source. There is also the possibility of the LDR being entirely operated by natural light, which would reduce the need for an electrical grid.
Technical Description
(Figure 1.0)
(Øyvind Nydal Dahl, 2013 Figure 1.3 schematic diagram)
(Figure 1.4 Tinkercad design)
Figure 1.4 is the Tinkercad design of the previous schematic. Within it the parts are placed in the positions necessary for proper functionality. Unlike the schematic, the tinkercad design shows the breadboard and the different wires used to connect each part. The breadboard is simply a tool used to prototype the project, and without it the schematic diagram could not be actualized. As shown in figure 1.3 the parts of the project separate from the breadboard and the wires include; a 9volt battery, a PNP transistor, Two resistors, a photoresistor and an LED. The Battery acts as the power source for the project and it can vary in voltage depending on how much light needs to be produced. The resistors act as the tools that “maintain specified values of voltage and current in the circuit”(Joseph 2021), and they are 100k ohms and 390 ohms respectively. The photoresistor is what makes the entire circuit respond to darkness and light. The LDR is connected in a small opening on the breadboard to control the amount of energy that goes to the LEDs.
Within the tinkercad simulation users are able to simulate night and day to test the effectiveness of the circuit. A PNP transistor was used instead of an NPN because “Voltage Allocation and Current Flow are Switched”(Difference Between an NPN and a PNP Transistor n.d). If an NPN was used the circuit would have reacted to light instead. Lastly, the Led is the visual aspect of the circuit. It’s how the project would be considered a success.
- Process of Innovation
Materials:
- Resistors
- Photoresistors ($2 per each)
- Leds bulbs( 5 cent per each)
- Electrical conductors (cables)
Building an LED bulb is simple, the materials needed is a small circuit, but there is no need for that; there are already small boards for which can be adapted to place the LDR. The bulb can be separated in 4 parts: the metal part which will be connected to the wall or the electricity source, the body which will contain the LDR and the small board that will provide the LED’s with electricity. Finally, we have the transparent part which helps to make the light bright.
LED bulbs are a bit more expensive than a standard bulb, which can cost you $1 to $2. For the different material used inside the LED to make it light up. An LED bulb can cost you $5 to $7.99 dollars per each bulb which may look expensive, but you will end up saving money through lower consumption of electricity. There are more durable LED’s that can live from 15 thousand, 30 thousand, or even 50 thousand hours, meaning 2 to 4 years. On the other hand, a standard bulb can only live for one year, but it may be less than that.
Reference:
- WatElectronics(July 18, 2019),“What is a Light Dependent Resistor and Its Applications”(Link)
- National Geographic Society, J. C. (2019, July 15). Light Pollution. National Geographic Society.(Link)
- Tom Harris, C. P. & W. F. (2002, January 31). How Light Emitting Diodes (LEDs) Work. HowStuffWorks.(Link)
- (2019, December 02). Light Pollution: The Dark Side of Lighting. Retrieved April 20, 2021, from(Link)
- Difference Between an NPN and a PNP Transistor. (n.d.). Retrieved April 24, 2021, from (Link)
- Joseph, A. (2021, January 12). Types of Resistors : Working and Their Color Code Calculations. Retrieved April 22, 2021, from (Link)
Self-Reflection
Just like the other assignments in this class, the most difficult part for me was brainstorming an idea that is an innovation. It felt like there were infinite options, yet no options at all. The possibilities were endless as we could come up with whatever we wanted, but it was difficult to come up with an innovation that did not already exist. The first idea we thought about were LEDs. Obviously, LEDs are already an object that exists, but we planned to improve them somehow at first. For the first few meetings we just researched LED’s and brainstormed what we could do to improve them. We also considered other innovations, such as a 3D Printer. Specifically, we read about how 3D printers are being used to print human organs. I was considering ways to make the process of 3D printing of organs faster and more streamlined. In the end though, we decided to go with the LEDs, but we mainly focused on LDRs, which are light dependent resistor. We talked about how LDRs can help reduce electricity usage and light pollution since the LDR allows to control the light level of LEDs. After, we went on to do the technical description to depict how the innovation works. I definitely feel like it was beneficial to work collaboratively with peers. It definitely came out to be a better project than what it would’ve been if we did it individually. Each of us editing and revised each other’s work and gave each other feedback on how to improve it. The whole process was pretty streamlined once we figured out what we wanted to do. I feel like it probably would’ve been better if we were in person as it would’ve made the whole experience much easier, especially since we weren’t all available at the same time. It wasn’t that hard to work together remotely, but I feel like we would’ve worked a little more efficiently if we were face to face. Besides that, the project was pretty good. The technical description wasn’t too hard because we already knew what to do from the last assignment. I was happy with the result of our paper and I think we did a good job working collaboratively.
