Iron Man 3 Chest Arc Reactor

I made this prop to wear to the Iron Man 3 release (and to test out some new technology for a future project).

Arc Reactor
Arc Reactor


The whole thing was designed in OpenSCAD and 3D printed in ABS (both the housing and the diffusor puck).  A Teensy 2 module drives the LED strip (WS2812 clone, 60 pixels/m) and is is wired up to a BLE112 module for communications.

You can control it via Bluetooth (no app yet, you hand craft a 1, 3, 6, or 7 byte message in a BLE explorer app to set a greyscale color, or one/two RGB colors and a ping-pong speed).  By default it boots up into ‘Arc reactor blue’ with a soft breathing animation.

Speeding up LPD8806 show() without hardware SPI

If you’re using LPD8806 LED strips and you can’t use the hardware SPI port (e.g., when using an Ethernet board), there are two other options in the Adafruit library: the default mode and ‘slowmo’ mode. The default mode is decent, but the flexibility of being able to choose the pins at runtime comes with a cost.

However, you can still get a decent speedup by defining your pin usage at compile time in a replacement show() function. I measured the time required to update an 86 LED strip using each method on an EtherTen board (Atmega328 @ 16 MHz, same as the Uno):

30.23 ms - Adafruit 'slowmo' method (digitalWrite)
7.76 ms - Adafruit default method (port pointers)
1.54 ms - Compile-time method
1.43 ms - Adafruit hardware SPI method

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Infected Omen Light Box

I pulled an all-nighter and designed/fabricated a LED edge lighting box plus etched plate in advance of the Gears 3 launch. The original plan was to slide an unused junk android tablet in and show some numbers from the stats dashboard in that central window, but I wasn’t able to get the tablet on the secure network at work, so now it’s just a pretty light box sitting on my desk. I almost slid my iPad in, but the slot I machined for the tablet is about 0.5 in too short for an iPad, though it had 0.75 in of slack for the target tablet.

The light gently pulsates / undulates around the border (driven by an Arduino), aiming to look a bit like the corrupted omen on the title screen.

The LED strip I used are LPD8806 driven strips from Adafruit, and they are a dream to use compared to the older Christmas light strand style strips I’ve used in the past. Each LED is individually addressable via a SPI-like interface to set a 21 bpp RGB color, and they have their own internal PWM clock, so you can fire and forget, no need to keep clocking them.

Also, Gears of War 3 is out, you should play it!

Aether converter cell

I was thinking of doing something Steampunk themed for Halloween, and thought I might spend a few hours prototyping a ‘raygun’ prop.  This aether cell as far as I got, it would serve as the ‘ammo cartridge’ for the raygun, sticking out of the back at a slight angle.

It’s got a red LED, a cyan ultrabright, and a UV LED, and the fluid is a mixture of diet tonic water, vodka, and highlighter fluid, so you get a very nice eerie glow with the UV LED on.

Aether converter cell in action

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