Changing Poi Colors Based On Speed And Velocity

September 11, 2014 by Matt Terndrup 5 Comments

LED toys have become synonymous with the underground rave culture as party-goers gaze into vortexes of spinning light known as poi. Most of these objects come pre-programmed, but some can be custom coded. However, only a few tap into an accelerometer changing the colorful circles of energy depending on how fast they move through space. One stunning example is this LED device called the ‘Center Flee’ that translates accelerometer data into sequences of alternating RGB colors.

The LED values are ‘printed’ to the tethered objects at specific points in the rotational arc. The devices are controlled with an Arduino, and a XBee wireless module transmits data to a computer nearby, eliminating the need to manually remove an SD card after each spinning session.

When spun, the poi acts like a colorful, twirling extension of the performer that produces a mesmerizing, vibrant effect. It’s nice to see the progression of glow sticks tied to shoelaces into g-force sensing devices that can captivate surrounding audiences.

Other examples of similar types of ideas include this accelerometer poi that was cut with a CNC machine and these LED staffs for the ultimate portable rave.

Below is a video playlist of the Center Flee being tested out.

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Driving WS2812B Pixels, With DMA Based SPI

September 10, 2014 by Edward Becker 18 Comments

Typically bit-banging an I/O line is the common method of driving the WS2812B (WS2811) RGB LEDs. However, this ties up precious microcontroller cycles while it waits around to flip a bit. A less processor intensive method is to use one of the built-in Serial Peripheral Interface (SPI) modules. This is done using specially crafted data and baud rate settings, that when shifted out over the Serial Data Out (SDO) pin, recreate the needed WS2812B signal timing. Even when running in SPI mode, your hardware TX buffer size will limit how many pixels you can update without CPU intervention.

[Henrik] gets around this limitation by using peripheral DMA (Direct Memory Access) to the SPI module in the Microchip PIC32MX250F128B microcontroller. Once properly configured, the DMA controller will auto increment through the defined section of DMA RAM, sending the pixel data over to the SPI module. Since the DMA controller takes care of the transfer, the micro is free to do other things. This makes all of DMA memory your display buffer. And leaves plenty of precious microcontroller cycles available to calculate what patterns you want the RGB LEDs to display.

Source code is available at the above link for those who would like to peruse, or try it out. This is part of [Henrik’s] Pixel Art Project. Video of DMA based SPI pixels after the break:

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Biofeedback Flowers At Burning Man

September 10, 2014 by Bryan Cockfield 14 Comments

Burning man, the premier desert-based convention, is a vacation for some. [Sam], on the other hand, points out that he is there to get his hands dirty. This year, he (with a team of six) built a set of 20 interactive lotus flowers that light up in sync with a heartbeat.

[Sam]’s biofeedback circuit is able to sense up to two heartbeats per flower. When a person’s heartbeat is detected, a set of high-power LEDs light up from the base of the stem upwards towards the petals for an incredible illuminated display of biofeedback.

The lotus flowers themselves aren’t anything to scoff at, either. They range from 8 to 18 feet high and are made out of steel and rowlux plastic. The circuit boards are all custom-made as well, with every part chosen to be as affordable as possible. The whole installation is powered by a deep-cycle marine battery and a set of 6V batteries, which can run all of the electronics in the flowers for the entire night before needing a recharge.

Burning man is a great example of art meeting technology. For other examples, check out this 2010 pyrotechnic ball, or head there yourself next August! Be sure to check out the videos and the project’s code on the project site as well.

Arduino-based LED Wedding Lights

August 31, 2014 by Matt Terndrup 15 Comments

Light (1 of 3) Light (2 of 3)

[Rob] created these amazing Bluetooth controlled LED lights for his daughter’s wedding adding a colorful ambient glow to the ceremony. Each item held a Neopixel ring and an Arduino microprocessor with a wireless module that could be individually addressed over a ‘mini-network.’ The main master station would receive commands from a Windows Phone. Usually we see Arduino-based projects being run with Android apps, so it’s nice to see that Microsoft is still present in the maker community.

The enclosures and translucent vases that sit atop the devices were 3D printed. All eight of the matrimonial units synchronized with each other, and the colors could be changed by sliding the settings bar on the app. [Rob] says that it was a lot of fun to build, and jokingly stated that it kept him “out of all the less important aspects of the ceremony. (food choice, decor, venue, who to marry etc etc).” The outcome was a beautiful arrangement of tabletop lighting for the wedding. A demo of [Rob]’s setup can be seen in the video below.

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Proximity Sensing LEDs Can Add A New Dynamic To Your Projects

August 30, 2014 by James Hobson 19 Comments

Proximity Sensing LEDs

Looking for a fun and easy way to add a bit more interaction to your LED-laden projects? Why not turn them into proximity sensing LEDs?

Our hacker, [Will], is just getting into designing his own PCBs. He was looking for a simple project to try out that wouldn’t be too hard to design and manufacture a PCB for, so he came up with this clever little interactive LED array.

It’s actually a very simple circuit which also makes it super easy to build on a prototyping breadboard. Each proximity sensing LED is made up of five components. Three resistors, an LED, an IR LED, and a photo transistor. The IR LED is chosen specifically for the type of photo transistor being used — in this case, it emits a wavelength of 880nm, which is the type of light the photo transistor recognizes.

These components are wired in a manner that the IR LEDs are always on. The normal LED is wired in series with the photo transistor, and thus the LED only turns on when the photo transistor sees reflected 880nm light bounced back at it by whatever object you wave over top.

What would be really cool is if you added some 555 timers to the mix and had a delay before the LEDs fade away — then you could have a huge array that leaves motion trails long after you’ve triggered the sensors!

[via Dangerous Prototypes]

LED Light Staffs For The Ultimate Portable Rave

August 28, 2014 by Matt Terndrup 15 Comments

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[risknc] and [mpinner] have been working on a couple of LED light staff designs for a while now and have come up with a prototype that can light up the night with an array of streaming colors. There is even a dial that can turn up and down the brightness.

Originally, [risknc] began developing his own project at SpaceX and dove further into the idea right before Burning Man. The visual effects, when twirled through the air, produced an extremely bright flow of energy that can be seen circling around the user.

The 8ft long carbon fiber staff was stuffed to the edges with RGB LEDs. Neopixel strips at 60 LED per meter were used to alternate between colors, and a whole bunch of white capable LEDs were embedded into the staff as well. One of early designs was purposefully left at a local hackerspace called Crashspace in Culver City, California. Photos of community members trying it out surfaced on the hackerspace’s website. In addition, a description of the staff and a few high-quality photos of the ‘Sparkle Stick’ were uploaded on to the Suprmasv projects page. Searching through the pictures reveal an instance that shows the LED light staff being used during a flow session with a fire poi spinner in the background. Perhaps there is a way to combine LEDs and fire? Anyways, a later version of the staff was tested out at the 2014 Maker Faire in San Francisco.

Full specs and logs of the project can be found on Hackaday.io. A quick video of [mpinner]’s light staff being spun around comes up after the break. In the video, it looks like they are testing it out outside of Crashspace as they run through the darkness of the alleyway in the back, lighting up the area with a nice LED glow. Plans for the future include building a bunch of them and wirelessly syncing them up. CAD models will be uploaded soon as well.

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LED Water Wheel Display Is Dekatron-tastic!

August 27, 2014 by Adam Fabio 10 Comments

led-ring-final

Sometimes, it’s the simple things that mesmerize. [JohnS_AZ] has created a simple dekatron style LED ring, but we can’t seem to stop watching his video. [John’s] LED ring began as a visual indicator for his Hackaday Prize entry, a water consumption display. Judging by his website, [John] is a bit of a display nut. Nixie tubes and huge clocks feature prominently.

We’ve seen plenty of LED projects using the trusty 74xx595 8-bit shift register. [John] personally isn’t a fan, as the entire chip is only rated to drive about 50mA. While hackers routinely push the chip several times past this limit, [John] found a chip designed for the task in the Texas Instruments TLC59282 16 channel constant current LED driver. (PDF link) While more expensive than the ‘595, the 59282 makes life much easier. Only one resistor is needed at the chip’s current sense pin, rather than a current-limiting resistor for each LED. The 59282 also provides a blank input, which is perfect for driving with PWM.

[John] designed a simple PCB with a the 59282 driving a ring of 16 LEDs. While he waited for the boards to come in, he wrote some test code for a Microchip PIC16F1509. [John’s] code is not optimized, but that makes it easy to see exactly which bit patterns he’s writing to the LEDs. It all makes for a great demo, and reminds us of those old Dekatron tubes.
It’s the demo video that makes this project. Click past the break and give it a watch. After several long days of judging entries, a really nice LED ring might be just what the doctor ordered.

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