Old LED Marquee Turned Embedded Video Player

April 26, 2013 by Mike Szczys 12 Comments

driving-led-marquee-with-rpi

[Sprite_TM] is was sent an old LED Marquee by an anonymous fan of his hacking projects. The display isn’t full color, but it’s large — 224 by 48 pixels — and he figured he could render some okay images with the bi-color diodes. In the end, he replaced the controller and turned it into a video player.

The original system work well enough, but the 100 MHz 486 industrial style PC that drove the display seems a little comical these days. After giving it a spin and testing out how it drives the display [Sprite] hooked up an FTDI chip and managed to get it playing video from his computer. Above you can see part of the opening sequence of The Simpsons.

Now that he had learned its secrets he set out to give it an embedded controller. His first attempt was with a Carambola board which he’s worked with before. That proved to be a little slow for all the pixel data he was pushing so he upgraded to a Raspberry Pi and never looked back. You can see the demo video after the jump.

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Mood Lamp/notifier Uses Neat Modular PCB Design

April 20, 2013 by Mike Szczys 28 Comments

mood-lamp-with-modular-electronics

Not only does this mood lamp which [J. Sutton] built look great, but we love the modular design he adopted when building the circuit boards.

If you’re building something that is going to sit on your desk for some time it just has to look good. We think that he achieved that, using a small block of oak as the base, and a cloudy white cube of unknown origin as a diffuser. Notice that the different colors are not mixed. There’s a baffle inside the diffuser that keeps them separate as early testing showed any combination of intensities was resulting in nearly the same shade of color.

The part we really like is the modular design of his circuit boards. The project is based around a Teensy++ 2.0 board. He first built a PCB baseboard which feature two SIL sockets to accept the legs of the Teensy. There is a third SIL socket which accepts some long legs from the LED host board, letting it perch on top of the Teensy.

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Asynchronous Fireflies Use Few Parts

April 19, 2013 by Mike Szczys 38 Comments

led-firefly

[Karl Lunt] wrote in to share his LED firefly project. His goals for the project were to develop a low-power, low parts count module that can sense when it’s dark and then mimic the blinking patterns you’d associate with its biological namesake.

We like his design which uses a coin cell battery holder as the chassis for the project. The ATtiny13 driving the hardware is held in place by the two power wires. This lets him flash new firmware by rotating the chip and plugging in a little adapter he build. The LED connection might look a bit peculiar to you. It has a resistor in parallel, which doesn’t satisfy the normal role of a current limiting resistor. That’s by design. [Karl] is driving the LED without any current limiting, which should be just fine with the 3V battery and short illumination time of the diode. The resistor comes into play when he uses the LED as a light sensor. Past firefly projects included light dependent resistors to detect light and synchronize multiple units. [Karl] is foregoing the LDR, using the LED with a resistor in parallel to combat the capacitive qualities of the diode. As we mentioned, this senses ambient light, but we’d love to see an update that also uses the LED to synchronize a set of the devices.

Another Way To Look At Charlieplexing

April 8, 2013 by Mike Szczys 7 Comments

Charlieplexing is a technique that allows you to drive a larger number of LEDs than wouldn’t be possible with the same number of I/O pins on a traditional multiplexed matrix. If we lost you there just think of it as lots of blinky lights connected to a small number of pins. It works by leveraging the one-way nature of a diode. Current will only flow through an LED in one direction so if you hook up your display in a clever way you can drive multiple LEDs from one I/O by switching the polarity of that pin between voltage and ground. [M.Rule] recently looked at using Charlieplexing with LED modules. His conceptual approach to the problem is different from those we remember seeing before and it’s worth a look.

Instead of just using the formula to calculate how many LEDs he can drive [M.Rule] is using a table of I/O pins to establish how many and in what order these displays can be connected. Each colored set of blocks represents an LED module. The graphic above shows how 18-pin can be utilized. He even filled in the unused pin combinations with input buttons.

Microscope Ring Light With A Number Of Different Features

April 3, 2013 by Mike Szczys 41 Comments

microscope-ring-light

Microscopes magnify light. It makes sense that having more light reflecting off of the subject will result in a better magnified image. And so we come to Aziz! Light! It’s [Steve’s] LED light ring for a stereo microscope. It’s also a shout out to one of our favorite Sci-Fi movies.

He’s not messing around with this microscope. We’ve already seen his custom stand and camera add-on. This is no exception. The device uses a fab-house PCB which he designed. It boasts a dual-ring of white LEDs. But the controls don’t simply stop with on and off. He’s included two rotary encoders, three momentary push switches, and three LEDs as a user interface. This is all shown off in his demo video after the break.

An ATtiny1634 is responsible for controlling the device. When turned on it gently ramps the light up to medium brightness. This can be adjusted with one of the rotary encoders. If there are shadows or other issues one of the push buttons can be used to change the mode, allowing a rotary encoder to select different lighting patterns to remedy the situation. There are even different setting for driving the inner and outer rings of LEDs.

We haven’t worked with any high-end optical microscopy. Are these features something that is available on commercial hardware, or is [Steve] forging new ground here?

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Visualize Twitter With An LED Matrix

March 31, 2013 by Mike Szczys 3 Comments

What’s your favorite color? Don’t tell us, Tweet it to [Sebastian’s] favorite color Twitter display and you’ll be contributing to the artwork hanging on his wall.

This answers a very important question, what do you do with your projects after they’re completed? For us the best part is the planning and building. Once it’s done the thrill is pretty much gone for us. We haven’t even switched on our Ping Pong clock in over a year. But [Sebastian] recently dusted his 10×10 LED matrix for this project.

Tweets are parsed by a Python project he wrote to try out the Twitter API. It looks for a set list of colors . He asserts that people aren’t that creative when you solicit their favorite color but to prove him wrong we’re going to say our favorite is Amaranth. After it finds the color it pushes it to the next pixel in the spiraling pattern shown above. But wait, there’s more! To give the pixels a but if extra meaning he uses the total length of the tweet to set intensity.

If you need a Titter enabled hack that displays a bit more specific data you’ll want something that can actually display what was Tweeted.

Ikea Dioder Ambilight Hack

March 28, 2013 by Ryan Fitzpatrick 8 Comments

There are a lot of hacks out there for Ikea’s Dioder LED light set. [Lambertus] wanted to create an easy and affordable ambilight while keeping the hardware modifications to a minimum. He also wanted anyone to be able to easily duplicate his work. He recently wrote in to share his successful solution.

The customizations boil down to three main steps: solder the ICSP connector wires to the test points on the Dioder PCB, connect a PIC programmer to the ICSP port (and reprogram), and attach a 5V RS-232 device to the ICSP port. The software was the most difficult part of the procedure for [Lambertus]. The PIC16F684 didn’t contain the required UART and PWM controllers, so he had to get crafty. Fortunately he’s done all the work for us, and lists the necessary .hex file he created on his site.

By adding support to boblight, his new ambilight is working with his media center very nicely. There’s a little demo video after the break.

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