Fire In The Palm Of Your Hand

For as long as super-heroes have existed, they have inspired hacker projects. For [Everett Bradford], emulating the character Pyro from X-Men has been an on and off project for the last decade. His latest version, Pyro System V4, integrates quite a bit of control electronics to give the rather convincing effect of mind-controlled fire in the palm of his hand. (Video, embedded below.)

The system is a motor-actuated slider strapped to [Everett]’s forearm, which pushes a pivoting end-effector with an integrated butane burner into the palm of his hand. The slider runs on 4 mm linear bearings actuated by a small geared DC motor using cables. The end effector is spring-loaded to push it into the palm and integrates a high voltage ignition arc generator circuit, nozzle, and capacitive activation button.

The butane gas canister and the valve was cannibalized from a small blow torch lighter, and the valve is actuated by another geared DC motor. The valve actuator, slide actuator, and end-effector hinge all integrate position feedback via hall effect sensors and magnets. The sensor in the hinge allows the slide to actively correct for the angle of the user’s wrist, keeping the end effector in the middle of the palm.

The control circuit is split into two parts. One PIC16 microcontroller runs all the motion control and position sensing, while a PIC18 connected to a small touch screen handles user interface, control parameters, and ignition. The touch screen proved especially useful for control parameters during development without needing to connect to a laptop.

Some of [Everett]’s previous version had a much more impressive (and dangerous) flame but was also very bulky. We think this latest version strikes a pretty good balance regarding compactness and achieving convincing illusion.

[Colin Furze] is another name commonly associated with fire-breathing contraptions, but they have a proven history of landing him in hospital.

15 thoughts on “Fire In The Palm Of Your Hand

      1. I was fixing my printer in my underwear one day and passed my soldering iron to the other hand… By grabbing the hot end. I immediately let go and it fell directly towards my jewels. I don’t think I’ve ever moved so fast in my life. Made a small burn mark on the boxers but my important bits escaped completely unscathed.

    1. I have heard rumors that there is a subculture of people that like to propel thousands of pounds of metal at high speeds around strangers using explosions from gasoline. I hope that dangerous practice doesn’t catch on!

  1. Really nice to see such a (with all due respect) ‘joke’ project go this far, thats actually very well done.

    Since he asks, i would suggest next step is one more refinement pass and a nice sleek enclosure, then use it to get a job at a movie props department ^^

  2. Okay, here’s my two cents.

    Firstly, this project is pretty safe – about as safe as holding a candle. Butane has a high vapor pressure, which means that it won’t “wet” an object and burn it like gasoline or other more dangerous substances. About the worst he can do with this is singe his eyebrows, and that only if he punctures the tank or the valve sticks open. Magic shops already sell burning item props meant to be held in the palm of your hand with integrated igniter wheels (but this one is much better).

    For improvements, I might look into making the chassis motor quieter. Hearing the obvious motorized mechanism would detract from an audience experience.

    Next, make the extension skin colored to mostly hide it. The coloring doesn’t have to be perfect, but a black object against the palm is pretty obvious. The “real” flaming hand appliances you get in magic shops (yes, I have some of these) comes painted in a pinkish skin color.

    Then, add a control mechanism on the opposite side of the body somewhere; for example, in the left hand or in the left pocket. (Ideally wire it to a switch inside the left shoe that he can activate with his toes… but that doesn’t interfere with normal walking. Activating such a switch isn’t that hard with a little practice, depending on his native kinesthetic ability.) The audience will be looking at his hand, and won’t notice that he’s got his other hand in his pocket controlling the mechanism.

    (If you go “wired” for this, use the wires from an old pair of earbuds – regular wire will quickly break from the constant bending. Better would be a remote device, depending on your level of comfort with programming – you can get remote BLE switches on eBay for about a buck that are used to remotely trigger cameras.)

    And finally, make up an “act” of some sort that frames the device without calling attention to the device itself. You can just show off “I built a device that shoots flames”, but to really show off it would be more interesting to say “I have a superpower”, hold up a bic lighter, flick it on, shoot out a gout of flame, and then show that you are only holding a lighter. Something similar to that, maybe slightly more elaborate and interesting with a bit of backstory: ever since I was young… my parents always had to keep me away from candles… etc etc.

    An act not *what* I just described – but something *like* that that you come up with. It might be interesting to ask a professional magician for advice – if you find the right one, for the cost of buying them a couple of beers they might have good suggestions on how to punch up the effect.

    Hope that helps. Neat project – looks very good.

    1. > Butane has a high vapor pressure, which means that it won’t “wet” an object

      I and my pants would like to differ. Liquid butane out of a can or a tricked up lighter held upside down WILL wet objects and stick to them while it’s burning.

    2. ” “I have a superpower”, hold up a bic lighter, flick it on, shoot out a gout of flame, and then show that you are only holding a lighter. ”

      Transfer the lighter to the other hand, as if you are going to do something with it there, and let the audience discover a flame remains burning in the other hand.

      The “BIC” could also be a dead one with a remote control inside for the mechanism.

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