Documenting Poorly Documented LED Strips

While [Drew] was in China for the Dangerous Prototypes Hacker Camp, he picked up some very bright, very shiny, and very cheap LED strips. They’re 5 meter “5050” 12V strips with 20 LEDs per meter for about $15 a spool. A good deal, you might think until you look at the datasheet for the controller. If you want an example of how not to document something, this is it.

A normal person would balk at the documentation, whereas [Drew] decided to play around with these strips. He figured out how to control them, and his efforts will surely help hundreds in search of bright, shiny, glowy things.

You are expected to tell the difference between 'GMODE', 'OMODE' and 'CMODE' in this pinout.
You are expected to tell the difference between ‘GMODE’, ‘OMODE’ and ‘CMODE’ in this pinout.

The datasheet for the LPD6803 controller in this strip – available from Adafruit here – is hilarious. The chip takes in clocked data in the order of Green, Red, and Blue. If anyone can explain why it’s not RGB, please do so. Choice phrasing includes, “VOUT is saturation voltage of the output polar to the grand” and “it is important to which later chip built-in PLL regernate circuit can work in gear.” Apparently the word ‘color’ means ‘gray’ in whatever dialect this datasheet was translated into.

Despite this Hackaday-quality grammar, [Drew] somehow figured out how to control this LED strip. He ended up driving it with an LPC1768 Mbed microcontroller and made a demo program with a few simple animations. You can see a video of that below.

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Brighten Your Day with Motion Controlled Cabinet Light

[Thomas Snow] found himself in a bit of a pickle. His kitchen lights didn’t adequately light his counter-tops. So instead of inventing a light bending device that could warp space-time enough to get the light where it needs to go, he decided to take the easy road and installed a motion controlled LED strip under the cabinets.

Now, these aren’t just any ‘ol motion control lights. Not only is [Thomas] able to turn the lights on and off with a wave of his hand, he can control the brightness as well. He’s doing the magic with an ultrasonic range sensor and PIR sensor. An ATTiny85 ties everything together to form the completed system.

The PIR sensor was incorporated because [Thomas] didn’t want to bug his pets with the 40kHz chirp from the ultrasonic sensor. So it only comes on when the PIR sensor sees your hand. Be sure to check out [Thomas’s] project for full source and schematics.

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Sound Reactive Drums of Trailing Light

If you’re going to be the drummer in a band for a Back to the Future themed New Years Eve party, you really need to add something to your gig that captures that kitschy futuristic ambiance as seen by the 80s. Rainbow LEDs will do the trick.

For his drum set’s reactive trailing light display, [Alec Smecher] was inspired by a similar project he’d seen in the past where Neopixels were added to a regular drum kit and activated with several individual microphones. Since the microphones ultimately heard all of the thundering noise from every drum and cymbal at once, there was a lot of bleed over in the response of the LEDs. To remedy this, [Alec] used piezo pickups which listen to discrete surface vibrations rather than sound in order to clean up the effect produced by the lights. Each of the five LED strips lining the stands of his cymbal and inside of his drums were programmed to react with a burst of light equal in brightness to the intensity of the vibration sensed by the piezo.

To insure everything kept together amidst all the constant motion and shaking during performance, [Alec] soldered his connections directly onto his Trinket’s pins as well as the fragile pickup of the piezo. The pickup of the sensors were taped directly against the skin of his drums and along the inside of each cymbal to maximize responsiveness. After ringing in the new year appropriately as the ‘band from the future’, [Alec] reports that his colorful addition worked fantastic the whole night.

Those interested in building their own can find a nice schematic on [Alec’s] blog as well as the code he used on github. Difficulty level taken into account, this is a great first project for a musician who has yet to dabble in electronics… and seeing that it’s a brand new year, there’s no better time to have a go at something new.

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Motion Through Time Painted in Light

Photographer [Stephen Orlando] has an awesome body of work that focuses on human motion. The images he captures with colored light and a camera set up in a setting of choice tell a story of time in a way that’s visually stunning.

[Stephen] has experimented with various types of action. He’s attached LED strips onto props like oars in order to capture the rhythmic movements of rowing, or directly onto parts of the body to visualize more chaotic gestures, like the forms of a martial artist. His camera is set up to take long exposures, soaking in the light as it plots itself through space over time.

karateLight

Though this isn’t a hack directly in itself, [Stephen’s] experimentation with time and light is a great case of technology being added to the arsenal of traditional mediums we’re accustomed to seeing in the production of artistic work. The clean execution of his idea to tell a story about what we don’t typically get to see by use of light should inspire all of us who love to play around with LEDs in our projects. Sometimes the more interesting aspects of our work are created in the negative space we forget to consider.

The next time you find yourself working on a hack, look at what you’re creating from a perspective beyond its original context. For example, 3D printing with a delta robot is a bit of a departure from it’s original purpose as a pick and place machine. Even further yet is the concept of using one to draw images in space with light. Often the process of somethings creation, as well as the byproduct of what it took to make it, is just as worthy of investigation. Don’t forget to search between the lines… that’s where the magic is.

Measuring the Length of WS2812 Strips

[Tim] discovered a simple way to measure the length of WS2812 addressable LED strips from a microcontroller. This is great for any project that can have an arbitrary length of addressable LED strip attached to it.

The simplest (and perhaps most reliable) way to measure strip length is by feeding the serial output pin of the end of the strip back to the microcontroller. The microcontroller keeps clocking bits into the strip until it receives data from the end of the strip. [Tim] didn’t want to run an additional signal to the end of his strip, so he found another solution.

[Tim] used the ADC of his microcontroller (an ATtiny) to measure supply voltage droop as LEDs are turned on. Each LED draws around 60mA at full brightness, so [Tim] sequentially turned on each LED and watched the ADC for slight voltage changes. If the voltage changed, there must be an LED at that address. [Tim] does note that this method is extremely dependent on the power supply used and only works on short strips. Check out his blog post for more details.

HammerPong Game Takes Pong to New Heights

large scoreboard with lots of flashy lights

[Jason] is back at it again with another new twist on the technically sophisticated and advanced game of Pong. Fashioned in a ‘Chuck E. Cheese’ style platform, the two players stand side by side each other with large foam hammers. A wack sends the 32 bit ARM powered dot skyward and then back down to the other player, where another wack will send the dot back whence it came. A brightly lit scoreboard keeps track of how many dots slip by.

[Jason] is a veteran of pong inspired games, but putting the HammerPong game together brought with it some new challenges. After being unable to squeeze a few MDF panels into his car, and fighting off flies, yard debris and pet dander that were trying to attach themselves to his freshly painted artwork, [Jason] managed to get his project completed.

The HammerPong is powered by an Arduino Due that controls six WS2812 LED strips and runs the background code. Various latches, shift registers and power transistors control the lights and scoreboard. Be sure to check out the linked project for more detail, and take a look at the video demonstration after the break.

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Building a Network Controllable RGB LED Lamp from an Old Scanner

EthernetLamp

Being able to use one of your old projects to make a new one better can be quite satisfying. [Steve] from Hackshed did just this: he integrated an Arduino based webserver into a new network controllable RGB lamp.

What makes this lamp unique is that the RGB LED bar comes from an old Epson scanner. Recycling leftover parts from old projects or derelict electronics is truly the hacker way. After determining the pinout and correct voltage to run the LEDs at, the fun began. With the LED bar working correctly, the next step was to integrate an Arduino based webserver. Using an SD card to host the website and an Ethernet Arduino shield, the LEDs become network controllable. Without missing a beat, [Steve] integrated a Javascript based color picker that supports multiple web browsers. This allows the interface to look quite professional. Be sure to watch the lamp in action after the break!

The overall result is an amazing color changing lamp that works perfectly. All that is left to do is create a case for it, or integrate it into an existing lamp. This is a great way to use an LED strip that would have otherwise gone to waste. If you can’t find a scanner with a color wand like this one, you can always start with an RGB strip.

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