Punch-Activated Flamethrower
Using an Arduino Nano, Butane, and an assortment of hardware store components, I try to mimic the "firebending" antagonists from a childhood show.
Like many kids who grew up watching Avatar: The Last Airbender, I thought the firebenders were incredibly cool. I mean, truly, what is cooler than being able to telekinetically manipulate fire through martial arts movements? I often fantasized about having this ability myself. So, as a slightly more competent teenager, I realized this dream by building a wrist-mounted, martial-arts-motion-tracking flamethrower.
Flamethrower |  |
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| Figure 1: The completed wrist-mounted flamethrower apparatus | Figure 2: Demonstration of punch-activated flame projection |
The device is built around an Arduino Nano connected to a 3D accelerometer that continuously monitors acceleration. With the acceleration data we can decide what motion — or sequence of motions — will deem the user worthy of harnessing elemental phlogiston. For example, we could say that the device will only release flame when the user's arm is pulled back in a controlled way, held still for a short time to show composure, and released in a controlled punch that is between a set range of acceleration.
Once the Arduino has detected one of the pre-set action sequences, it opens a small pneumatic valve connected to an on-board pressurized gas chamber (an enclosed steel pipe). This releases a stream of butane in the direction of the punch. There is then a small, set delay — to let the gas spread for a better visual effect — before a high-voltage arc lighter ignites the gas.
To see it in action, check out the video below!
This project drew heavy inspiration from Allen Pan's flamethrower build.