555s For Your Mouse And R/C Airplane

February 1, 2011 by Noah Dunker 18 Comments

[lenny] decided to build a 555-based auto-firing mouse based on a 555 after seeing a similar PIC-based project we posted earlier. Lenny’s version is self-contained in one mouse without requiring a second mouse to act as the rapid-fire button. It uses only a handful of components, costs less than $5 to build, and doesn’t require any programming.

But then, [wfdudley] shakes things up a bit. He added a 4022 counter IC and some diodes to act as logical “OR” gates in order to create a unique blinking pattern (short-short-long) for the lights on a friend’s RC airplane. While this project involves more components, it’s definitely a trickier problem to solve with a 555 timer IC. We love seeing people choosing simplicity in design over popular off-the-shelf microcontroller frameworks as these two have done.

Don’t forget, the 555 Design Contest is still going strong, and you’ve got the entire month of February to submit your awesome designs. We wanted to highlight two of the more clever 555-based hacks that we’ve had in our backlog for a while, though.

How To Build A Ping-pong Ball Display

January 31, 2011 by Mike Szczys 41 Comments

If you’ve been lusting after your own glowing display we’re here to help by sharing some simple building techniques that will result in an interesting project like the one you see above. This is a super-accurate clock That uses ping-pong balls as diffusers for LEDs, but with a little know-how you can turn this into a full marquee display. Join me after break where I’ll share the details of the project and give you everything you need to know to build your own.

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Insane Covert IR Illumination

January 31, 2011 by Caleb Kraft 37 Comments

[Onironaut] over at lucidscience sent us a link to his latest project, some IR illumination panels. At first, we were mildly enticed by his usual high standard of photography and description. It was just an array of LEDs though. Still, we kept hitting the “next page” button because he goes into such great detail. Then we saw version two. Instead of simply being an array of IR LEDs mounted outside for his security camera, he has mounted 1536 IR LEDs inside an old flat panel monitor. That’s a fake monitor producing 180 watts of IR light, and we think that’s even at half power! He replaced the screen of the display with one way mirror, so you would have no idea that it isn’t just a normal screen sitting on his desk. Great job as usual [Onironaut].

Conways’ Wall Of Life And Whiteboard Emporium

January 27, 2011 by Mike Szczys 6 Comments

White board beats chalk board, LED marquee beats white board, and an LED white board trumps them all.

This hybrid lets you draw on the surface with dry erase markers while Conway’s game of life plays out underneath. [Bert] sent us this tip after seeing yesterday’s office marquee. This version is quite similar in appearance but the guts are very different. Inside you’ll find a Parallax SX28 microcontroller doing the heavy lifting. The display is multiplexed but they didn’t go with a common 595 shift register, but a beefier MAX6979 LED driver. We’re not too familiar with this part but it does have a lot of nice features like constant current, and automatic shutdown if serial data stalls for more than 1 second. This is a low-side driver so transistors are used to connect voltage to the rows; the opposite from the setup we looked at yesterday. This was built several years ago and is still working happily even though its permanent home is a breadboard. Source code can be found on this page.

12 Foot LED Display Keeps Your Office Informed

January 26, 2011 by Mike Szczys 20 Comments

Don’t reach for a sticky note when you need to leave a message for your office mates, write it down on a 12 foot LED marquee. [Kitesurfer1404] built this for his home office, but we’re sure he’ll find fun stuff to use it for. The display has 512 LEDs driven by plain old 595 shift registers for the high-side columns, with an ULN2803A Darlington Array to pull the eight rows to ground. The whole thing is controlled by an ATmega8 via a serial connection. Our compliments to the builder for accurately drilling a grid of 64×8 holes in each hardboard panel of the display. The buses for each row and column also look nice and clean. For the final look a 79% light transmittance frosted acrylic panel was added to diffuse the light.

We used the same method to build our LED pumpkin. Transistors ran the low side, and if we had needed more columns, shift registers are a popular go-to for I/O expansion. Check out that project to learn more about display multiplexing.

Scrolling Marquee Made From GE Christmas Lights

January 11, 2011 by Mike Szczys 23 Comments

[John Riney] picked up three strands of addressable Christmas lights and used them to make a scrolling marquee. You may remember that the G-35 lights were hacked at the beginning of December, and we saw a project or two that involved these fun toys.

In order to make the display [John] modified the original packing material to hold three strands in a six by eighteen grid for a total of 108 pixels. In the video after the break he points out one interesting feature of the strand that we don’t remember from looking at the original hack; each bulb’s address is not fixed, it can be set after power-up. This works the same way as sending color data, except that you just send the address. This makes controlling a grid like this extremely easy from a microcontroller programming standpoint. Once all of the addresses have dropped down the serial bus, you’re ready to start sending color and intensity data packets.

The setup is fast, bright, and beautiful, taking just three pins of an Arduino for control. The only thing holding us back from trying this ourselves is the $150 price tag. But that was before the holiday, and we have heard some whispers about closeout deals on this product.

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OLED Displays And Small Microcontrollers

January 9, 2011 by Mike Szczys 22 Comments

If you’ve ever thought of utilizing a small and inexpensive OLED display in your project [Rossum] has the details you need to get started. In the past we’ve seen him take a tour of available LCD screens and this is much the same, detailing his look at three different models. In the video after the break each is connected to a driver board that he made. The boards have two important components, the first is a boost driver for the 12-16V input the screens need, the second is an octal buffer necessary if you are using a 5V microcontroller. These take care of the hardware considerations, making it simple to drive them with a chip of your choosing.

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