LED Hacks

1868 Articles

LED display controlled by Bluetooth speaker

How Many Hacks In An LED Display?

June 6, 2017 by 10 Comments

There are so many nice hacks in [Joekutz]’s retro LED display project that it’s hard to know where to start. There’s his DIY LED display controlled by an Arduino UNO. To have some text or picture for the display, he’s wired the output of a Bluetooth speaker directly to the Arduino, and sends it speaker tones that encode the text to draw. And as if that wasn’t enough, he’s hacked a quartz driver board from an analog clock to use the display as a clock as well.

Let’s start with the LED matrix display, perhaps the best excuse for trying your hand at shift registers. This display uses two such 8-bit shift registers daisy chained together feeding two 8-bit Darlington arrays. The display has ten rows of sixteen columns, and you guessed it, the columns are controlled by the sixteen shift registers. Two Arduino pins tell the shift registers which column to turn on. The rows are turned on and off using ten transistors controlled by ten more Arduino pins. Scanning at 80 frames per second he gets a nice, flickerless display.

To make both the LED matrix circuit board and the control board, [Joekutz] carved out isolation paths in copper clad boards using his homemade CNC mill. Be sure to check out the first video below to see his misadventures with it that ultimately led to his gorgeous boards.

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540 PCBs Make A Giant LED Cube

June 2, 2017 by 21 Comments

Just about anyone can make a simple LED cube. But what if you want to make a 1-meter cube using 512 LEDs? [Hari] wanted to do it, so he created two different kinds of LED boards using EasyEDA. There are 270  of each type of board, for a total of 540 (there are only 512 LEDs, so we guess he got some spares due to how the small boards panelized). The goal is to combine these boards to form a cube measuring over three feet on each side.

To simplify wiring, the boards are made to daisy chain like a cordwood module. However, to get things to line up, each column of LED boards have to rotate 90 degrees. You can see several videos about the project below.

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Float Spectrum, A Sound-Reactive Installation

May 29, 2017 by 5 Comments

[Sam Kent] and friends built a sound-reactive LED display as part of the Leeds (UK) Digital Festival and exhibited it at Hyde Park Book Club. The installation consists of a grid of 25 tubes, each one made out of four recycled 2-liter bottles equipped with a string of a dozen WS2812B LEDs controlled by a central Arduino.

Connected to the Arduino via USB, a computer running a Processing application analyzes the audio input and tells the Arduino which LEDs to light and when. The red tube in the center responds to bass, the ring of yellow LEDs mids, and the outer ring glows blue in response to high frequencies.

It’s amazing how just a simple 2-liter makes a rather effective light pipe to amplify the effect of each burst of color. We think this installation would be a great addition to the magnificent LED dance floor we recently looked at from our friends up in Toronto. If you seek an LED art piece that’s a lot easier to move around, what you’re after is a rave shopping cart.

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Ever Hear Of The Ford Cylon?

May 25, 2017 by 42 Comments

OK, we haven’t heard of a Ford Cylon either. However, there is now a Mustang Cobra out there that has been given a famous Cylon characteristic. [Monta Elkins] picked himself up an aftermarket third brake light assembly, hacked it, and installed it on said Mustang.

The brake light assembly contains 12 LEDs, which unfortunately, are not individually addressable. Additionally, by the looks of it, the brake light housing was not meant to be opened up. That didn’t get [Monta] down though. There’s more than one way to skin a cat, but he chose to use a hot knife to open the assembly, which worked quite well. A rotary cutter tool was used to cut the traces between the LEDs allowing them to be individually controlled with an Arduino. A Bluetooth module allows him to control the new brake light from his smartphone. There are different modes (including a special mode that he shows off at the end of the video) that can be selected via a Bluetooth Terminal app.

There is no schematic or code link in the video itself or the description, but [Monta] did hit the high points. Therefore, it shouldn’t be too hard to replicate.

This isn’t the first brake light hack we’ve featured. This one goes way beyond just animated lights.  This one requires no programming. Rather wear your brake light? We’ve got your back(pack).

Gravity Defying Drips Of A Bike Pump Controlled Fountain

May 22, 2017 by 9 Comments

People love to see a trick that fools their senses. This truism was in play at the Crash Space booth this weekend as [Steve Goldstein] and [Kevin Jordan] showed off a drip fountain controlled by a bike pump.

These optical illusion drip fountains use strobing light to seemingly freeze dripping water in mid-air. We’ve seen this before several times (the work of Hackaday alum [Mathieu Stephan] comes to mind) but never with a user input quite as delightful as a bike pump. It’s connected to an air pressure sensor that is monitored by the Arduino that strobes the lights. As someone works the pump, the falling droplets appear to slow, stop, and then begin flowing against gravity.

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3D Printing Custom LED Bar Graphs

May 16, 2017 by 26 Comments

[BikerGlen] wanted to spice up his zombie containment unit (see video below) so he designed and 3D printed some very cool looking bar graphs. Apparently, you can get curved bar graph LEDs, but only if you buy a fairly large quantity. Hand soldering discrete LEDs at the perfect angle would be frustrating, but with a 3D printed jig, it was a piece of cake.

The devices use a MAX6954 LED driver, so it needs very few parts and takes commands via SPI. The chips were not cheap, but the small size and high integration sold [Glen] on it.

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A Very Large VU Meter Indeed

May 16, 2017 by 18 Comments

It used to be a must-have on any hi-fi, a pair of moving coil meters or LED bar graphs, the VU meter. Your 1980s boombox would have had them, for example. VU, for “Volume Units”, is a measure of audio level, and the fashion for its visual measure in consumer audio equipment seems now to have largely passed.

The LED bar graph VU meters were invariably driven by the LM3915, a chip that contains a resistor ladder and a stack of comparators which can drive LEDs directly. [Juvar] has taken an LM3915, and used it to drive a set of opto-isolated triacs which in turn drive a stack of appropriately coloured mains LED bulbs concealed within an Ikea Vidja lamp. The result is a huge and very bright VU meter that is as much a lighting effect as it is a measure of sound level.

He’s posted a video of the lights in action, and we’ve placed it below the break. There is a cameo appearance from his cat, and one can’t escape the feeling that it is wasted on a small room and would be at its best before a dance floor. Still, it’s a neat lighting effect and a new use for a classic integrated circuit.

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