An Experiment In Shift Registers And Multiplexed LEDs

March 18, 2015 by Brian Benchoff 15 Comments

[Kratz] is working on a WiFi controlled scoreboard, but before building the full-scale version, he thought it would be wise to test out the multiplexing technique for the display. The experiment worked, but unless this scoreboard is for a foosball table, he still has a lot of work ahead of him.

The design of this prototype display is pretty simple, with just two ‘595 shift registers feeding bits to the display. Sixteen NPN transistors are being used to sink and source current to the display. It’s a relatively simple circuit, allowing [Kratz] to fit nine seven-segment displays on a small board with only six wires – ground, two V+ for the logic and LEDs, clock, data, and latch – going to the microcontroller.

There were a few snags in the design; the data is clocked in on a rising edge, but an extra falling edge was required before latching. [Kratz] can’t figure out the reason for this, and it might just be a timing issue.

A Motor, An Arduino And A Whole Bunch Of Laser Cutting

March 16, 2015 by James Hobson 14 Comments

[Guido] was recently commissioned to build a kinetic sculpture for a client who wanted something unique. What he came up with is really awesome.

It’s called ORBIS: The Wooden Kinetic & Lighting Sculpture. It mounts to the wall and provides a focal point for the room – a bright flashy spinning one at that! Does it just stay there and do random things? Nope, of course not! [Guido] built it with a unique control box, two Arduino 2560’s and an Xbee to communicate between them.

He was told to design it using old and new technologies so he’s got a rotary phone dial on the side of the box which allows the user to change through the different modes.

Switches on top also let you change the color of the sculpture and the speed at which it moves around. Since it’s wireless it can be easily set on the coffee table and become an instant conversation starter.

See it in action after the break.

Continue reading “A Motor, An Arduino And A Whole Bunch Of Laser Cutting” →

Glowing LED Cubes From The Future

March 9, 2015 by Rich Bremer 28 Comments

Sometimes people don’t believe you when you tell them something. You may have to go out of your way to convince those skeptics. Well, [AlexTheGreat] was having a hard time convincing people that he was from the future. He thought building some cool looking glowing LED cubes would help his story.

Underneath the fancy exterior covering is a cube made from pieces of clear acrylic sheet that are hot-glued together. There isn’t much inside the cube, just an LED, resistor, button cell battery and an on/off switch. A hole in one of the cube sides allows access to the on/off switch. Once all the components are verified to work, the interior of the cube is filled with hot glue to diffuse the light.

The exterior is thin sheet metal cut into cool shapes and bent around the plastic cube. Like the rest of the components, these metal covers are held on with hot glue. They do a great job of blocking the LED light ensuring it shines out of the creatively arranged gaps. We’re not sure if these will convince anyone that [AlexTheGreat] is from the future but they are certainly darn cool looking!

Nixie Inspired 7 Segment Display

March 3, 2015 by Anool Mahidharia 15 Comments

The supply of Nixie tubes from east European stock piles is still enough to keep their prices down. But once those start dwindling, prices will move north. Besides, if you want to use them, you need to work with high voltage supplies and worry about not getting zapped while trying to debug a circuit. [FilleK] had some time to spare and decided to build a cheaper substitute for a real nixie tube using a regular 7 segment LED display.

We have already seen this hack before, in the Arduino-based ENIGMA replica. But [FilleK] improved on that by adding an extra LED to simulate the radiant glow typical of Nixie tubes. His project log describes the fairly straightforward process using parts that can be found easily. A piece of plastic, painted in a shade of copper and fixed around the 7 segment display, acts as a nice baffle to contain and reflect the ambient glow of the back-light LED. A nice improvement would be to add a random flicker to the background LED. Maybe add an Octal socket (the decimal point had to be nixed though!), and cap it in a proper glass tube. If you’d rather work with the real McCoy, check out our archives.

LED Sound Board Is Not Your Father

February 26, 2015 by James Hobson 10 Comments

Who doesn’t like Star Wars, LEDs, and music? [Stathack] was looking for a unique piece of art to put in his living room… so he decided to make his own Vader EQ.

The EQ is a massive 4′ x 5′ piece made from plywood and MDF. [Stathack] traced the familiar helmet onto it by using a projector to project the outline onto the surface. Not having access to an extra large CNC or laser, he then painstakingly used a jigsaw to cut out all the white pieces of the design — holy cow.

This process only took weeks and weeks of sanding, filling and sanding again due to the excellent precision of a jigsaw.

Once that was all done, he created the backing plate out of MDF to provide structural support and mounting locations for the LEDs. Bit of spray paint later and a simple circuit with the Arduino and it’s both done, and awesome.

Continue reading “LED Sound Board Is Not Your Father” →

A Colorful Clock For Toddlers

February 24, 2015 by Rick Osgood 34 Comments

[Don] and his wife were looking for a way to teach their two-year old daughter how to tell time. She understood the difference between day and night, but she wasn’t old enough to really comprehend telling the actual time. [Don’s] solution was to simplify the problem by breaking time down into colored chunks representing different tasks or activities. For example, if the clock is yellow that might indicate that it’s time to play. If it’s purple, then it’s time to clean up your room.

[Don] started with a small, battery operated $10 clock from a local retailer. The simple clock had a digital readout with some spare room inside the case for extra components. It was also heavy enough to stay put on the counter or on a shelf. Don opened up the clock and got to work with his Dremel to free up some extra space. He then added a ShiftBrite module as a back light. The ShiftBrite is a high-brightness LED module that is controllable via Serial. This allows [Don] to set the back light to any color he wants.

[Don] already had a Raspberry Pi running his DIY baby monitor, so he opted to just hijack the same device to control the ShiftBrite. [Don] started out using a Hive13 GitHub repo to control the LED, but he found that it wasn’t suitable for this project. He ended up forking the project and altering it. His alterations allow him to set specific colors and then exit the program by typing a single command into the command line.

The color of the ShiftBrite is changed according to a schedule defined in the system’s crontab. [Don] installed Minicron, which provides a nice web interface to make it more pleasant to alter the cron job’s on the system. Now [Don] can easily adjust his daughter’s schedule via web page as needed.

Animated LED Valentine Heart

February 13, 2015 by Rick Osgood 3 Comments

With only a week left until Valentine’s day, [Henry] needed to think on his feet. He wanted to build something for his girlfriend but with limited time, he needed to work with what he had available. After scrounging up some parts and a bit of CAD work, he ended up with a nice animated LED Valentine heart.

[Henry] had a bunch of WS2812 LEDs left over from an older project. These surface mount LED’s are very cool. They come in a small form factor and include red, green, and blue LEDs all in a single package. On top of that, they have a built-in control circuit which makes each LED individually addressable. It’s similar to the LED strips we’ve seen in the past, only now the control circuit is built right into the LED.

Starting with the LEDs, [Henry] decided to build a large animated heart. Being a stickler for details, he worked out the perfect LED placement by beginning his design with three concentric heart shapes. The hearts were plotted in Excel and were then scaled until he ended up with something he liked. This final design showed where to place each LED.

The next step was to design the PCB in Altium Designer. [Henry’s] design is two-sided with large copper planes on either side. He opted to make good use of the extra copper surface by etching a custom design into the back with his girlfriend’s name. He included a space for the ATMega48 chip which would be running the animations. Finally, he sent the design off to a fab house and managed to get it back 48 hours later.

After soldering all of the components in place, [Henry] programmed up a few animations for the LEDs. He also built a custom frame to house the PCB. The frame includes a white screen that diffuses and softens the light from the LEDs. The final product looks great and is sure to win any geek’s heart. Continue reading “Animated LED Valentine Heart” →