Simple LED Project to Spice Up Your Halloween Party

[Paul’s] project is a great example of how you can take a simple project and turn it into something more interesting. He built himself a jack-o-lantern with an Internet controlled RGB LED embedded inside.

[Paul] first wired up an RGB LED to a Raspberry Pi. He was sure to wire up each color using a 100ohm resistor to prevent the LED from burning out. The web interface was written in Python. The interface is pretty simple. It consists of three text fields. The user enters a value between 0 and 255 for each of the three LED colors. The program then lights up the LED accordingly.

[Paul] realized he would need a diffuser for the LED in order to really see the blended colors properly. Instead of using a common solution like a ping-pong ball, he opted to get festive and use a plastic jack-o-lantern. [Paul] removed the original incandescent bulb from the lantern and mounted the LED inside instead. The inside of the pumpkin is painted white, so it easily diffuses the light. The result is a jack-o-lantern that glows different colors as defined by his party guests. Be sure to check out the demonstration video below.

Prototype LED Light Suit runs off of a NES Power Glove

[Greg’s] been playing around with wearable hacks for quite some time now, and he’s decided to add a new twist for his latest LED light suit (Mk 4) — An ancient NES Power Glove to control it.

He was inspired by the band Hypercrush who had a music video where one of the guys was wearing a laser-shooting power glove — awesome. Having already made light suits before, he thought it’d be fun to do something similar.

The suit is controlled by an Arduino Pro Mini which has been hacked into the Power Glove for ultimate button pushing capabilities. He’s using 5 meter LED strips of the classic WS2812  RGB variety, which allow for individual LEDs to be addressed using a single pin. It’s powered by a 5V 2A USB battery pack, and he’s made all the components very modular, you could even say it’s “plug and play”!

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A Very Bright LED Jacket

Last year, [Ytai] went to Burning Man for the first time. He was a bit inexperienced, and lacked the lumens to make him visible on the Playa. This year, he made up for it by building an extra bright LED Jacket.

The jacket consists of 48 LEDs, at 150 lumens each. Each RGB LED module was placed on its own PCB, and controlled by the tiny PIC12F1571 microcontroller. This microcontroller was a great fit since it has three PWM channels (one for each color) and costs 50 cents. Firmware on the PIC allows the boards to be daisy-chained together to reduce wiring. This was done by using a protocol similar to the popular WS2811 LEDs.

Assembling 50 of the boards presented a challenge. This was addressed by using surface mount components, a solder stencil from OSH Stencils, an electric skillet, and a good amount of patience. The final cost of each module was about $3.

With 50 of the boards assembled, a two layer jacket was sewn up. The electronics were sandwiched between these two fabric layers, which gave the jacket a clean look. A wrist mounted controller allows the wearer to select different patterns.

For a full rundown of the jacket, check out the video after the break.

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A Water Activated Flashlight?

We’ve all seen lemon batteries or potato clocks, but have you ever seen a water activated battery?

[Nathan Stubblefield] was an American inventor (born 1860) who never got quite as much recognition as some of the other great inventors of the time, [Tesla, Bell, Edison etc] — though he did demonstrate some very interesting wireless telephony technology. In addition to dabbling with invisible radio waves, [Stubblefield] filed a patent for something called an Earth Battery, which makes use of two coils of dissimilar materials (a voltaic couple) submerged in water (or moist earth). As you can imagine, it wasn’t overly effective, nor efficient by any means — but it worked.

[Lasersaber] has been playing around with the “Stubblefield Coil” recently, and designed a working flashlight using the theory. He designed a 3D printed coil holder which allows you to easily wrap copper and magnesium strips around it to create the coil. Three of these cells go together in series to produce your water battery (and handle of the flashlight).

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NYC Maker Faire: The Logistics of Manufacturing Pentagons

Most of the Maker Faire attendees have spent weeks or months putting together their projects. [Matt] is doing things a little differently. He brought two thousand boards, each containing twelve pentagon PCBs with individually addressable LEDs mounted in the center. This weekend, he, his team, and anyone else who can wield a soldering iron will be assembling these pentagon panels into a gigantic glowing crystal.

Last year, [Matt] put together a Kickstarter for Blinkytape, a WS2812 LED strip with an Arduino on one end of the strip to generate patterns of colors. This year, [Matt] is moving into three dimensions with a system of pentagons with a single RGB LED mounted in the center. The pentagons can be soldered together into a regular polyhedra or a convoluted wall of LEDs that form a geometric crystal pattern of blinkyness. The Kickstarter for the BlinkyTile should be up before the faire is over.

[Matt] has a few tips for anyone wanting to run their own Kickstarter: don’t have a lot of SKUs. [Matt] only has to keep track of a single panel of twelve pentagons. Compare this to other failed Kickstarters with dozens of options, several colors, and a few stretch goals, and you quickly see why many, many Kickstarters fail. [Matt] is just selling one thing.

Changing Poi Colors Based on Speed and Velocity

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

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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