APR26
Add backlight to LCD
If you have an LCD display that does not have a backlight, you can easily modify it to add your own. On the bottom side of the LCD glass you can find polarising and reflecting films. This mod process involves pealing off the reflecting film so that LED light can travel through the glass to enlighten the display.
It is very important not to peal off the polarising film and if that should happen, it should be glued back to the LCD glass. LED light source is made out of LEDs and some sort of light-medium. For that purpose, some kind of diffused plastic can be used.
Source: AP Digital light
APR23
Toner transfer PCBs and copper tinning
If you don't know how PCBs are made with a toner transfer method, you should check this video out. It is presented here because the process is described in detail, from thorough copper cleaning to etching in ferrum chloride and for the final step - instant tinning of PCB traces for oxidation protection.
Forget about tinning with a soldering iron, this process is carried out very elegantly with a liquid tinning solution. In just a few seconds all PCB traces are protected from oxidation and eager to accept some solder.
Source: AP Digital light
APR22
Charge your phone while you walk
Have no fear of loosing power to your mobile phone anymore - fashion gurus look away now. As funny as it looks, this little thing will harvest energy of your lunch and transform it into electric energy for charging your phone. It is a very simple solution though - hollow out your shoe, left or right and stick in a generator from a generator-flashlight.
There are actually two generators in a shoe with an addition of a spring to push the lever to the starting position. After that, just solder the appropriate charging cable for your phone and off you go! It is capable of generating enough power to charge a phone or iPOD while you walk. Pretty nice thing!
Source: Flagella
APR21
How to make killer PCBs and solder paste stencils
This is a photo etching procedure but it doesn't involve the use of photo lacquer. It uses dry photo resist films. Films are laminated onto the PCB boards and later exposed to UV light source.
There is also a UV exposing box with vacuum to press the artwork onto the PCB. This results in improved resolution and PCB quality. Vacuum is made with fish tank pump. After developing a basic circuit board, another two films are applied and UV-exposed with soldermask and stopmask layers. What really caught my attention is the process of making solder paste stencils. It is made in the same way as the PCB but the good thing is that the material is a very thin sheet of aluminium taken from a beer can. Excellent idea and a perfect material for this use!
Source: incoherent
APR20
Double sided PCB UV LED exposure box
Here is a very nicely built double sided PCB UV exposure box made out of wood, glass and UV LEDs. Exposure time is about 2-3 minutes, but that depends on photo lacquer thickness and age.
There are two panels with 84 UV LEDs on each, that is 168 UV LEDs in total. One panel draws 700mA from a 12V source. It is recommended that 2000mcd LEDs are used with peak wavelength of 400nm. All diodes are soldered on a veroboard which was probably a great advantage since minimum of 336 holes had to be drilled.
Source: djhamer
APR10
Sundial LED clock
Here is a very interesting concept of indoors sundial clock. A sundial is a device that measures time by the position of the Sun. Since indoors we don't get the Sun to cast a proper shadow for these purposes, it can be replaced with, yes, good old LEDs.
This shadow clock can show all three "hands"; hours just like a real sundial clock, minutes and seconds. Each shadow, or hand, is cast from a different light source - a ring, and each ring is of a different color (RGB). So, there are three rings, each having 12 LEDs (36 LEDs in total) and it is all multiplexed and controlled with AVR microcontroller.
There will probably be a kit of this cool clock soon, so check it out!
Source: Evil Mad Scientist
APR2
CC1101 RF modem + 250mW amplifier published
Here is my home-built, cloth iron soldered, range extender for CC1101 (included onboard) RF transceiver chip from Texas Instruments. You could say that it is a CC1101+CC2591, but for 868/920MHz band. I used MAX2233 RF amplifier from Maxim-IC. It can deliver up to +24dBm (250mW) of RF amplification with +10dBm of input.
After adding RF amplifier, original power of 10mW is boosted to almost 250mW or 1/4W. MAX2233 RF amp can deliver up to 250mW when powered by 3.6V, and since I used 3.3V LDO on my board, the output RF power is little less than that.
MAR24
Lemon battery
You probably know about a battery that can be built by using a lemon (or onion, potato, grape...) and two electrodes of a different type of metals. With that we can only get around 0.5 to 1V.
This battery is made out of 4 cells, weights just 0.85g and can supply power for a bright LED for 60 minutes. The best part of it is that you don't need to carry a lemon around with you. You only need 4 drops of lemon juice and you got your self a 3.5V 35mAh battery.
To make this battery you will need a zinc wire, some copper wire and a paper tissue that will act as a lemon juice storage compartment.
Source: madaeon
