MAY18
LED flickering with Arduino
In this LED project, three LEDs and Arduino are used to create realistic fire effect. This device can be used in a fake fireplace, or even in a real one for these hot summer nights where you don't want to heat up the room any further.
Diffused LEDs are preferred for the effect to be more realistic. In case of clear LEDs, you could diffuse the light with a piece of paper like it is shown in the video. Source code is written in C and is available for download on project page.
Source: earthshine
MAY15
Make your own wireless power transfer
What would it be like if there were no wires tangling behind our desk? Wireless power transfer is not new concept, today we can find many devices that rely on wireless power transfer such as electric tooth brushes or even computer mouse that powers itself from the pad.
Here you can see how easy it is to make your own wireless power transfer system. In fact, this is just a functional presentation of this concept that any of you could do at home. All that is required is good old LED, capacitor, two coils and a source of AC power. AC signal can be generated with function generator and probably even with NE555. For maximum power transfer it is important to fine-tune the coils with the frequency of AC signal.
Source: robotkid249
MAY13
Small autonomous magnetic robots
These are small autonomous magnetic robots that can travel on vertical surfaces such as: elevators, fridges or even whiteboards.
The robots have three light sensors each, which they use to interact with the outside world. They have three personalities which can be changed by covering one of three light sensors. So, the personalities are: Red, which makes robot move fast towards the objects; Green: which makes robot move a bit slower avoiding obstacles and Yellow: which makes robot move very slow and stop when it detects object in front of it. Components used in this robot are hacked servo motors, light sensors, Arduino microcontroller and a few passives.
Source: Stacey Kuznetsov
MAY11
Make your own LED from SiC
How about making your own LED? It is really simple, you just need some SiC (Silicon Carbide or Carborundum) crystal, electrodes and electric current. The phenomenon was discovered accidentally by an American radio engineer in 1907, and the first LED using this material was produced in 1960 into a working blue LED.
Here you can see a simple green LED from Carborundum crystal. It is important to clamp the crystal with positive electrode. After that, the current must be limited to around 30mA because more will heat up the crystal. Now, where the negative electrode (a needle) is touching the crystal a light in various colors should be produced. Color of the produced light depends on the electric current and the electrodes location on the crystal.
Source: Michael T. Lippert
MAY9
Home made photovoltaic solar cell
Here is a low efficiency home made photovoltaic (solar) cell made out of two copper plates, some liquid and housing.
This liquid in which two plates rest is a solution of sodium bicarbonate or table (kitchen) salt. The bigger copper plate was previously baked on a kitchen stove for about 30 minutes to produce cuprous oxide. This cell can not be used to power some current hungry devices because it delivers only 50uA at 0.1V. This does not make it any less interesting because it can be used as light detector or light meter, and it should be able to power a pocket calculator.
Source: alessiof76
MAY8
Wireless POV display
As the authors stated, "a POV display is a display created by rotating an array of LEDs rapidly. Due to the fact that human eyes can only render so many images per second, the fast spinning LEDs seem like a solid display".
This modular RGB POV display is a final work of two students from Cornell university. It is possible to write custom messages from PC via wireless XBee connection and even update firmware. Microcontroller used in this project is Atmega644 and it is all built on two PCB boards: main board with microcontroller and LED board with 96 LEDs. Position detection of rotating part is accomplished by using Hall effect sensor. Source code is written in AVR GCC C and it is available for download on the project page.
Source: Jonathan Diamond, Honghao Tian
MAY6
LED sensor keyboard for a piano
This is a final project of two students on Cornell university. It is a single octave piano implemented on Atmega664 microcontroller. The interesting thing about this project is the keyboard made out of nothing but LEDs.
Each key consists of 9 LEDs where the middle LED acts as a light sensor. Remaining 8 LEDs are used to light up the fingers. When a finger (or another object) gets close enough, the light reflects from emitting LEDs to middle sensor-LED. The project source code is written in AVR GCC C and is available for download.
Source: Cristina Guzman, Joe Vulih
MAY4
DIY contactless bike dynamo
It is very important to have lights on your bicycle but it can be very boring to replace those batteries. A classic bike dynamo has a few disadvantages such as slowing down the bike and making excessive noise while rubbing off of a tire. There are contactless dynamos, but why buying one when you can build one yourself?
This bicycle light is made out of three LEDs and a charge capacitor. It is powered by a DIY contactless dynamo made from a relay coil and some hard drive magnets. The circuit is constructed so that one LED is kept steady on while driving and the other two blinking.
Source: vbnicolau
