User:Skwon9642/ENES100/Project 3

Project Preference
Wireless charging

shaker table

blob

beat bearing

Lego

Problem Statement
This project, we are to work on design as well as making a prototype of wireless electricity. we are to light up an LED without any wires directly connected to the led.

Project Plan
we will begin by researching about the basics on how wireless electricity works. Then we will get into what kinds of materials we will need in order to create a magnetic field. After that, we will find a circuit diagram that explains how we need to connect the materials. Then we will come up with several designs and schematics for making the LED light up.

Week 1 Narrative
This week, I read up on the previous groups progress as well as watching and reading documents that might be helpful for us in the weeks to come. This is my first exposure to wireless electricity so I had to read quite a bit and in detail as well as look up vocabulary that I haven't been exposed to. Many videos I found online were about wirelessly charging cellphones. Some of the videos stated the pros and cons of wireless charging.

pros: no wire clutter, convenience, expandable(charge phone when set on a pad inside the car) cons: limited range, weak power compared to wired charging, not explored enough to reach full potential

Although our project won't be as complicated as trying to make a wireless charger, we need to light up an LED. Reading on previous groups, they ran into some hardships. It seems like they were able to convert the power from AC to DC, but not enough power was being transferred. They were getting a reading in the millivolts. They also had trouble which method worked best in conducting and transmitting power.

I plan to work on those areas where the last group had problems.

Week 2 Narrative
My task this week was to find materials needed for the project and learn about magnetic fields.

Since this was my first exposure to electricity, I went back and learned about the basics.

I learned about the difference between AC and DC. This MIT website helped me understand about the differrence.

AC: Very high voltage (in the 1000s) that are efficient in delivering power in low voltages. Ex: Lamp

DC: Small sources of power which are useful in powering every day electronics. Ex: Flashlight

Laptops are powered by both AC and DC. It gets the AC power source from the wall outlet and gets converting into DC by a transfomer. Transformers are a mechanism that is basically a coil of wires that converts high voltage into lower voltage to be used by household electronics.

A simple way to describe our method of wireless electricity: powering up the first coil will create a magnetic field around itself in limited range. then the second coil with the same diameter and coil length will pick up and be in "sync" with the magnetic field which will power the LED.

some basic formulas are:

Ampere's Law - If there is a motion of charge (current), there is always a circulation of magnetic fields associated with it. ( B is proportional to l)

Faraday Induction - If there is a change in the magnetic field, there is a voltage created in that magnetic field (V is proportional to dB/dt)

Lenz's Law - the voltage and current always flow in opposite direction. If there are 2 coils, each will flow in opposite direction (V = -dB/dt)

Learning about these laws, I now have a better understanding of how and why there is a magnetic field when a coil is powered up and how the second coil receives that power (although its significantly decreased).

Information obtained from:Here

This is a method that we tried, using an online tutorial, however, we could not get the first coil to power up because we didn't have the exact materials that the tutorial was using. We tried to improvise by adding multiple inductors with lower power (we needed 330umz, so we connected 3 100umz inductors in series). But we assumed that this method did not work. we will have to find other ways to power up the first coil. It seems like most of the work is to power up the first coil. Powering of the second coil should be automatic as long as the diameter and the number of coils are identical to the first coil.



credit for circuit:Link

Week 3 Narrative
The circuit we found in week 2 did not contain enough information. We found out this week that there were more pages that contained much more detailed information including the real picture of how the circuit was suppose to look.

Materials:

1. Power source

2. red LED

3. 1 transistor, type 2n2222a

4. 1 capacitor

5. 1 resistor 33k

6. 3 100 Uh(micro) inductors

we found a circuit diagram of the setup.

the negative end connects to the 3 100um inductors, which is connected to the emitter pin of the transistor. the positive end connects to the 33k resistor and the capacitor. the capacitor is connected to the base pin of the transistor. finally, the 2 ends of the coil is connected to the collector pin of the transistor and the ends of the resistor+capacitor.

Initially, we didn't know that the different pins of the transistors do different things. We thought all the pins were the same, but we later found out that the pins are specific.

as seen in the transistor diagram, pin 1 is the emitter, pin 2 is the base, and pin 3 is the collector. the picture on the right shows which way the transistors should go. It also matches with the picture in the circuit diagram.

Another crucial thing we learned is that the way the inductor is connected determines the power of induction. Since the lab didn't have a 330um inductor, we found 3 100um inductors and had them connected together. At first, we connected it in parallel, but what that did was it actually reduced the inductance because parallel means the powers get DIVIDED, not added. If we were to add the inductance, we need to connect them in series, which means that the inductors are connected like a train. ---100um---100um---100um---  <<< like so.

After seeing the actual mechanism made by the user, we tried to duplicate the exact same thing. We called this the first setup

This did not light up the LED. But we were getting about 9 volts throught the whole circuit. We concluded that the second coil is not receiving the power from the first coil. so we made a better coil. This coated copper coil had 5 coils, and about 2.5 inches in diameter. We called this the second setup.

Our second method did not work either...

after consulting with our professor, He gave us an idea of having a larger primary coil. This is our third setup

we powered up the large coil, and sure enough it did NOT light up the LED. Our professor gave us a magnetic field sensor to see whether the coil was producing any magnetic field. We measured the magnetic field at 0.3931mT, which according to the professor is very similar to an actual magnet. So we concluded that it did produce a magnetic field.

At this point, our group had no direction on what to do because we don't know exactly why the LED is not lighting up. So I decided to do more research on the parts we are using. We figured that if we actually know what we are using and not just following what others are doing on the internet, it would be more beneficial for us even if we don't get the LED to light up in the end.

Inductors: changes magnetic field and induce current(voltage). If the magnetic field is present, but not changing, it will NOT produce any current. Inductance is measured in Henrys. Henry = voltage/Amp. If current increases, the inductor resists the increase and thats how it makes wave-like properties in magnetic field that produce voltage. The coils need to be intersecting several times in order to create voltage.

Capacitors: Stores electricity. Capacitance is measured in Farad. Capacitance = Q(magnitude of charge on one of the conductors)/V

Transistors: Amplifies or switches electrical signal on/off.

http://html.alldatasheet.com/html-pdf/15068/PHILIPS/2N2222A/497/2/2N2222A.html

http://www.instructables.com/id/Wireless-L-E-D/?ALLSTEPS

Week 4 Narrative
''Describe in detail what you did for your team during the week (and weekend). Compare your task (from CDIO discuss page) with what you actually did.''