A Love Note In 14 Segments

July 14, 2013 by Brian Benchoff 11 Comments

[Terry] wanted to come up with a little electronics project for his kids, and also came up with something to keep the wife happy. It’s an adorable 14-segment love letter, pieced together with some leftover LED displays and a bit of solder.

There isn’t a microcontroller anywhere to be seen in this project – all the illuminated segments are tied to a switch, and aside from a few resistors there isn’t much to this circuit. The simplicity means it’s a great way for [Terry] to get his kids involved in electronics.

If you’re wondering why [Terry] didn’t throw multiple Arduinos, shift registers, or LED drivers into the build, consider this: sometimes segment displays can be static. The time circuit prop from Back to the Future (but not this modern recreation) was wired up in a similar manner, as only a few specific dates needed to be displayed. Either way, we’re thinking good on [Terry] for introducing his kids to a soldering iron and doing something special for his lady friend.

Computer Monitor Ambilight Clone Shows Remarkable Performance

July 13, 2013 by Mike Szczys 54 Comments

ambilight-project-discreet-led-boards

Check out this fantastic Ambilight clone for a computer monitor which [Brafilus] has been working on for a few years. It’s actually the third revision and watching the demo video below left our jaws agape.

Details are only available as comments on the YouTube page. But he’s given us just enough to be satisfied. His self-etched board hosts a PIC 18F14K50 microcontroller. It is talking to each of the 28 LED pixels which themselves live on tiny hunks of diy PCB as well. He wrote his own PC software in C# to capture the colors around the edges of the screen. He also worked hard to ensure there are plenty of tweaks available for true color matching between the monitor and what your eye sees bouncing off of the wall.

If you’re looking for something like this on your television set go back a couple of days and check out that standalone unit.

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Web Based Automation Courtesy Of Raspberry Pi

July 12, 2013 by Mike Szczys 6 Comments

web-based-automation-via-rpi

This project is a great example of the Raspberry Pi’s ability to eclipse Arduino when it comes to interaction. [Fall Deaf] mentions that he used to use an Arduino board with an Ethernet shield to add extensible interactivity to his project. But this one, which is a home automation lamp project, uses a Raspberry Pi instead. The concepts end up being very similar. But the cost of the hardware is less and the coding work is arguably orders of magnitude easier.

Don’t get us wrong, the hardware is fundamentally different. When you move from Arduino to RPi you lose some I/O pins and the low level control of them isn’t quite as straight-forward. But you also don’t have to program the thing in C. The Linux kernel handles the low level control which means you can write your scripts using Python. Because Python is an interpreted language the testing and debugging is much faster — no need to flash new code, just run the script again.

This project used the RPi GPIO to drive a strip of LEDs which use the WS2801 protocol. The board includes a NIC which makes it a snap to use as a web server. The smart phone controls seen above are served up from the Pi using jQuery. Right now there’s a cord running out of the lamp. But there should be plenty of room to use a screw-in outlet adapter and to hide the RPi and its PSU inside.

The board still has enough juice to drive other automation features too, like acting as a web radio server.

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LED Strip Pong As An Arduino Shield

July 6, 2013 by Mike Szczys 5 Comments

led-pong-strip

[Schuyler Sowa] has been hard at work on his own version of LED strip Pong. We’d say his work has really paid off. The game is robust and full of features.

Unlike the original Pong video game LED pong only has one axis on which the ball travels. The ball will bounce back if the button at the end of the strip is pressed when either of the last two LED pixels are illuminated. To add in a difficulty adjustment [Schuyler] included a poteniometer which alters the speed.

The game board is one meter of LED strip with individually addressable pixels. It cost a whopping $28 and was the second kind he tried after having trouble with the WS2801 based version (which often come as strings of lights). An Arduino board controls the game, with a shield made from protoboard to connect the components. In addition to the two user buttons — which were hacked out of a computer keyboard — you’ll notice a pair of seven segment displays acting as a scoreboard and an HD44780 character LCD rounding out the user interface.

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Is An LED Bow Tie Ironic Or Awesome?

July 4, 2013 by Mike Szczys 40 Comments

led-bowtie

We’re not exactly trend setters when it comes to wardrobe. And so the recent revival of the bow tie as an accepted dress item confounds us. We’re even more confused by [Arichter’s] LED bow tie. Sure, the hobby electronics part of it is a win… but when it comes to fashion is he making fun of the bow tie wearers, or setting a new standard?

The tie is made of three PCBs, which lets the wings sit on a bit different plane than the center. He populated the boards with about 100 RGB LED modules which he desoldered from a couple of meters of LED strip. They draw a lot of juice and to supply that he uses a boost converter. A standard Arduino UNO board controls the lights.

If you’re still sold on the bow tie form factor we’d like to direct your attention to this long-tie version. It doesn’t just show patterns, but plays a wicked game of Tetris with you as the game board.

[via Reddit]

Super-precise Light Painting From A Delta Robot

July 3, 2013 by Mike Szczys 13 Comments

delta-robot-light-painting

The points of those geometric shapes line up perfectly thanks to the delta robot arm controlling the light source. The source is a simple LED that can be switched on and off as it moves. A camera is set up in a dark room to keep the shutter open while the arm moves. We’re assuming that all of the light for the stationary objects in this image comes from the LED as well.

[Sick Sad] built the delta bot for just for this purpose. Check out the video below to see, and perhaps more importantly hear, the thing in motion. Seriously, the whine of the stepper motors is pretty awesome on this one.

The delta concept uses a central head on three arms angled down from above. If the LED is also pointed down it won’t light up the hardware and that’s why it doesn’t show up in the image. We’ve seen similar accuracy when using this style of machine for 3D printing. But if you don’t want to build a complicated machine you can try this out with a simple string plotter.

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Dimming LED Bulbs Designed To Replace Halogen Lamps

June 28, 2013 by Mike Szczys 40 Comments

dimming-led-halogen-replacements Halogen bulbs put out a lot of focused light but they do it at the expense of burning up a lot of Watts and generating a lot of heat. The cost for an LED replacement like the one seen disassembled above has come down quite a bit. This drove [Jonathan Foote] to purchase several units and he just couldn’t resist tearing them apart to try out a couple of hacks.

The one we find most interesting is a PWM based dimming hack he pulled off with an Arduino board and a FET. The bulbs are designed to be dimmable through the 12V supply that feeds the light fixture. But the relationship of dimmer position to light level is not linear and [Jonathan] figured he could do better. His solution is to add a FET in parallel with the LEDs. When activated it basically shunts the current around the diodes, resulting in a dimming. The video below shows this in action. We wonder if the flashing is a camera artifact or if you pick that up with your eye as well?

You may also be interested to read his post on Gelling the LED bulbs. Gels are colored filters for lights (or camera lenses). He cuts his preferred color down to size and inserts it between the LEDs and the lenses.

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