YourITronics

A valuable item in a hardware enthusiast’s arsenal, an ultra violet LED exposure box can be used with good results in making quality PCBs. LEDs are cheaper and safer than usual fluorescent lamps and also have a longer life span, so using high brightness UV LEDs is a great choice for an exposure box. The only downside is the longer exposure time, but this is an acceptable trade-off for most hobbyists.

The Exposure Box described here is a double sided one, with 84 5 mm UV LEDs on each side which need 700mA at 12V (that means 8.4 Watts for each panel). Therefore, the Exposure Box possesses 168 LEDs that add up to 16.8 Watts. It is important that the LEDs have at least 2000mcd brightness, a peak wavelength of less than 400nm and a viewing angle of at least 20 degrees. Other important components are the resistors (you will need 56 of them), the boards on which the LEDs are mounted and a power supply unit (this design uses 2x 160mm x 100mm pieces of Veroboard and a 12 Volt 24 Watt switch mode power supply).

The box itself is made of 6mm MDF, which can be easily shaped to build the case. The walls of the box are glued together and you will also have to drill holes for screws and the PSU connector. Take precautions when soldering the LEDs (check the polarity and don’t look directly to them when powered). You will also need a power switch and wiring to connect both panels to the PSU. When everything is done you could test the Exposure Box to see how it works using a piece of metal with photo resist.

A great project for home use, the UV LED Exposure Box can come in handy when making PCBs. Details on the components, assembly, soldering as well as schematics and other useful information in the link.

DIY UV LED Exposure Box: [Link] – [via]

“Love is a smoke raised with the fume of sighs,

Being purged, a fire sparkling in lovers’ eyes,

Being vexed, a sea nourished with lovers’ tears.

What is it else? A madness most discreet,

A choking gall and a preserving sweet.” (William Shakespeare)

When in love it can be important to find the right gifts for the right occasions. You know, the kind of thing that would bring a big smile to her face (followed by a wet kiss). It can be difficult to even remember to buy a present, let alone come up with something that will be appreciated. But fear not! I have found the solution to the problem and next Valentine’s Day you will be ready to really impress your sweetheart.

The Twinkling LED Heart of Love is a wonderful DIY project that will melt her heart and turn the next 14th of February into an unforgettable event. The Heart of Love is based on an Atmel AVR ATmega168 microcontroller coupled with 20 red LEDs that… blink randomly! The heart itself can be made of cardboard and, although red is the usual color for love-related objects, you can show your creativity and paint it something meaningful to you and your damsel. Like orange, if you’re both Netherlands soccer fans. Or black, if you’re black metal fans (pentagram is optional). Originality is usually appreciated, so go for it!

Tips and tricks: your Heart of Love is awesome and will surely knock her socks off, but don’t start explaining how it’s made, how the microcontroller works and so on, because she might start yawning and eventually fall asleep.

As for me… I think I’ll settle for a big bouquet of red roses, thank you very much.

Twinkling LED Heart of Love: [Link]

When i first saw this project i thought this could be turned into one of those dance steps learning game. The device consists of a 3×3 matrix of buttons. The system memorates the sequence in which you press the buttons and then plays it for you by lighting a LED under those buttons. You can also program multiple sequences. If you don’t press any button for a longer period of time, 4 seconds i believe, the device goes from recording to playback.

It is quite an interesting memory game, and can be transformed into a larger project. Like in one of those smart houses… in case you get lost this device will show you what path you took. On the other hand the algorithm behind this project can be used in beat generators, sequencers, power distribution sequencers and many others.

The Nove Bit as it was called is using Arduino and a TLC 5940 microcontroller. Source code is available for download as well as some instructions on how to build it.

9 Bits Visual Memory: [Link]

When POVs first appeared in advertising panels i used to wonder how are the characters diplayed. Seemed like magic. Later on i found out its because of our eyes’ inertia. Where you needed a large number of LEDs to display a message, now you just need to spin a few LEDs. The rotation speed must be fast enough to display at least 10 frames per second, complex graphics may require a higher value between 15 and 30 fps, movies usually have between 24 and 30 fps.

This project will show you with great details how to build such a device. It is not an easy build, it takes a fair amount of tweaking to get it to work but the results can be spectacular. The developers of this project decided on a modular design, putting an emphasis on interactivity. In the end they came up with a very customizable POV that can display images you upload wirelessly and that you can manage in real time.

The microcontroller used is the Atmega644, leds are driven with the MAX6971 IC and Xbee modules provide the wireless serial communication between the POV and the PC from which you upload the image. A GUI written in Java makes this task easy for you.

The LEDs are place on a different PCB than the rest of electronics, this way it can be easily upgraded to a 3D version. The motor part needs some attention because you will have to carefully balance the LED board, you will deal with a lot of vibrations and the speed of rotation can be quite dangerous. Also there will be some tweaking involved when you will build the brushing system to power up the LEDs.

The motor has a separate power supply so that the main PCB won’t pick up noise. A HALL sensor is used to count the rotations and give the position of the LED board. When real time management of the display is not desired, the POV can use the picture stored in its EEPROM.

In order to power it, you will need a 9v power adapter that can deliver at least 1.1A for the electronics boards. Since the motor is powered from different source, you will need to meet your motor’s requirments. The one used in the project had its own 5V/2.5A power supply.

The cost for building this project is a little higher than 50$ and you can further reduce that if you already have some of the needed parts . All schematics and code are found in the project, below you can see the POV in action.

2D Wireless POV Device: [Link] – [Via]

Interesting weekend project for those who still remember the awesome game or just to awake in your kids the knack for electronics here is the Space Invaders Button.

Fairly easy build, having the ATmega16P at the heart controlling an 8×8 bicolor LED matrix which will display animations of the game’s spaceships. Principle of operation is simple, the rows of the matrix are driven by a npn transistor in an emitter follower configuration.

This transistor provides the boost of current needed when two or more leds from the same row are on. The state of the ports driving these transistors is set on “high” logic level. You can now command each LED to light the color you want by setting the assigned port to “0″.

The ATmega16P will draw a small amount of current and can be powered by a 3V cell battery. The PCB is of small dimensions since SMT components are used, it’s even smaller than the LED matrix and thus hides nicely behind it.

It’s an easy project with little chance of failing and offers a nice lesson on how to handle the ports of your microcontroller. If you are doing this just for fun and you don’t care about dimension than the SMT can be avoided so that you can use the controller for other projects.

Happy soldering!

Space Invaders on a LED matrix: [Link]