Simple Circuit LEDs
The vast majority of the LEDs are a simple circuit - LED, resistor, and battery. Each armor piece was wired as an independent circuit, with its own battery source. A 4x AA battery pack was used for each armor piece - these provide nominally 6V. These LEDs were selected as they have a tight, strong forward beam that pairs well with the diffusion plastic. Since they have an average forward voltage of 3.5 V and 20 mA forward current, a 125 ohm resistor is used to finish the circuit. For details on this calculation use this tutorial. The LEDs were all wired in parallel with their own resistor.
A unique diffusion filter was used to get a clean yet transparent sci-fi glow. A specialty acrylic plastic from Acrylite has microscopic diffusive particles embedded that are able to diffuse light that is applied at its edge (see below video for a demonstration). This is a translucent glow - you are still able to see through the plastic albeit with a strong colored tint, so this was especially perfect for the helmet visor. When the LEDs are off, the plastic is fully transparent. These sheets were cut to shape and thermoformed to conform to the armor curves. The LEDs were then installed along the edge of the plastic at even intervals. Lastly, electrical tape was applied over the bare LEDs to prevent light bleed.
Arm Cannon Electronics
The arm cannon required a wider array of colors and also needed to simulate an energy beam shot. To accomplish this, I used an Arduino microcontroller (Adafruit Pro Trinket) with Neopixel RGB Leds (144 LED/m) for the strip lights on the top of the cannon body and two Neopixel rings, the 16 LED and the 12 LED for inside the barrel. Additionally, I installed a sound board with speakers that are also controlled by the Arduino, so when triggered the arm cannon looks and sounds like it’s firing a power beam!
While ambient, the arm cannon has it’s strip lighting illuminated in a gradient of orange to light yellow. When the first trigger button is pressed, the barrel right lights activate with bright white light coupled with the power beam sound, then a slightly delayed transition to yellow, orange, red, then off as a “cooldown” effect. When the second button is triggered, the “charge beam” is activated, which cycles both the barrel and strip lighting between yellow and white for a few seconds along with the charging sound. Then the “shot” is released, bursting the barrel with a bright white with the charge beam firing sound then going through a “cooldown” transition as with the regular shot.
Initial electronics assembly and effects test
Final effects test, fully installed