LED Tie Plays Tetris

June 25, 2013 by Brian Benchoff 10 Comments

tetris

[Bill] has been working with a gaggle of 8th graders this summer at a STEM camp, impressing them with his geeky attire such as an 8-bit and PCB ties, and an LED illuminated lab coat. The adolescent tinkerers asked him what he would be wearing on the last day. Not wanting to let the kids down, he whipped up an LED Tetris tie in an evening.

The Tetris board is a 20 x 4 grid of WS2811 based RGB LED strips, controlled by a Digispark dev board. Structurally, the tie is just two bits of card stock with the electronic bits sandwiched in between. and taped to a cheap clip-on. In the video below, the tie doesn’t have any sort of input to control the movement and rotation of blocks. [Bill] plans to update his tie with some rudimentary AI so it can play itself.

All the code is over on [Bill]’s git. It’s still a work in progress, but from the STEM student’s reaction, there’s a lot of potential in this tie.

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Lots Of Seven Segment Displays With A Single ATtiny

June 24, 2013 by Brian Benchoff 22 Comments

7seg

These days they’ve been replaced with character LCD displays or even brightly colored graphical displays, but if you’re trying to display data on one of your projects, there’s nothing like the classic red glow of a red seven segment display. [five volts] got his hands on a few ancient segmented displays, but controlling even one took up more microcontroller pins than he was ready to spare. The solution to this problem was to use a shift register and control multiple segment displays with an 8 pin microcontroller.

[volts] is using an ATtiny13 to control six seven segment displays. Each display is mounted on a hand-etched board, with a shift register and a handful of resistors soldered to the back. By having the microcontroller shift bits down the line, [volts] created an extremely easy to interface 6-digit segment display, and the entire device can be expanded even more.

The board files and schematics are available on [volt]’s project page. A great project if you’re just starting out to etch your own boards.

Adding RGB Backlight To Arcade Buttons

June 23, 2013 by Mike Szczys 15 Comments

These arcade buttons started out as illuminated buttons. But they were bulb-based which only allowed for one color. [Jon] and his friends at the Leeds Hackspace wanted to find a way to retro fit them with RGB LEDs, without changing the buttons themselves. The hack lets them replace the bulb with an addressable circuit board. The really interesting thing about it is that there is no separate interface for addressing. The communications happen on the voltage bus itself.

After deciding to include a microcontroller inside the button they built a test version using some protoboard to see if it would fit. Indeed there was enough room and the proof-of-concept led to the factory spun board which you see above. It has pads for two of the four LED module feet on either side, with the opposite end of the board fitting into the bulb receptacle. The voltage line is pulsed to send commands to the microcontroller. We’re interested in finding out exactly how that works but we’ll have to dig through the code before unlocking the secret.

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Water Tank Level Meter Prevents Overflow

June 16, 2013 by Mike Szczys 34 Comments

roof-water-tank-level-meter

Most of the homes in the area where [Raikut] lives have tanks on the roof to hold water. Each is filled from a well using a pump, with gravity serving as a way to pressurize the home’s water supply. The system isn’t automatic and requires the home owner to manually switch the pump on and off. [Raikut] made this process a lot easier by designing an LED bar indicator to monitor the water level.

The sensor is very simple. Each LED is basically its own circuit controlled by a transistor and a few resistors. A 5V signal is fed from 7805 linear regulator into the tank. The base of each transitor is connected to an insulated wire, each extending different depths in the tank. As the water rises it completes the circuit, illuminating the LED.

[Raikut] is conservation minded and built a buzzer circuit which is activated by the LED indicating the highest water level. If someone walks away from the pump switch while it’s filling the alarm will sound as it gets to the top and they can turn it off before it wastes water.

[via Reddit]

Super-cap Powered Blinky Jewelry Charged By The Sun Or USB

June 9, 2013 by Mike Szczys 16 Comments

blinky-jewelry-solar-supercap

We don’t see ourselves wearing these pendants around, but we still enjoyed taking a look at the design. These are just two from a wide range of offerings meant to be worn around and recharged by the sun. But a cloudy day won’t ruing the fun; they can be topped off via USB as well. Parts lists and schematics are included in the assembly Instructables for both the Owl and the Heart.

[Marty] and [Robin], a brother and sister developement/design team, were showing them off at the Sector67 hackerspace in Madison, WI. The single integrated circuit used in both is an OpAmp responsible for managing the blinking. The heart board has a calculator-style solar cell which charges that 0.5F supercap. The Owl has just a 0.022F coin-type capacitor and features a different style of solar harvester. The six components around the cap are each individual solar cells. [Marty] told us that they pump out a ton of juice in direct sunlight, outperforming the calculator-style cell. The opposite is true indoors. But as we’ve seen before, indoor solar harvesting is a tough game.

Need even more bling around your neck? Check out these LED matrix pendants.

Ambilight Clone Has Meaningful Amount Of Resolution

May 29, 2013 by Mike Szczys 37 Comments

We don’t have an Ambilight clone on our own home theater, but seeing this one in action makes us wonder if we shouldn’t add it to the ever-growing list of projects we need to tackle (right below that POV display we’ve been putting off for years). [Falldeaf] built the colored light augmentation system using a set of WS2801 controlled LED pixels. There are a lot of them, and this results in the ‘meaningful resolution’ we mentioned in the title. The image on the screen is the opening to a James Bond film. You’ll remember that the camera shot down a rifle barrel follows him as he walks across the screen. There’s enough LEDs here to have to the light follow him across the screen as well. This is a nice touch that we don’t see in every Ambilight clone project.

A frame of fake-wood angle bracket holds each LED pixel in place. The entire assembly attaches to the VESA mounting holes on the back of the television. An Arduino addresses the lights while the Boblight package processes the video to acquire the lighting instructions. We think the hue is a bit off, but otherwise it’s a solid offering.

We’re still hoping the Microsoft IllumiRoom becomes a thing.

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LED Etch-a-Sketch Built Without A Microcontroller

May 23, 2013 by Mike Szczys 21 Comments

logic-etch-a-sketch

This project is a wonderful example of what can be accomplished with a rather complicated logic circuit. It’s an Etch-a-Sketch made from a 16×16 LED grid. That in itself is only somewhat interesting. But when hearing about the features and that it is driven by logic chips we were unable to dream up how it was designed. There’s no schematic but the video commentary explains all.

The thing that confused us the most is that the cursor is shining brighter than the rest of the pixels. This is done with two different 555 times and a duty cycle trick. When you turn the trimpots the cursor position is tracked by some decade counters. Pixels in your path are written to a RAM chip which acts as the frame buffer. And there’s even a level conversion hack that let’s the display run at 15v to achieve the desired brightness. Top notch!
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