Baby, you’re a (legal, indoor) firework

Dr Lucy Rogers is more than just a human LED. She’s also an incredibly imaginative digital maker, ready and willing to void warranties in her quest to take things apart and put them back together again, better than before. With her recipe for legal, digital indoor fireworks, she does exactly that, leaving an electronic cigarette in a battered state as it produces the smoke effects for this awesome build.

In her IBM blog post, Lucy offers a basic rundown of the build. While it may not be a complete how-to for building the firecrackers, the provided GitHub link and commentary should be enough for the seasoned maker to attempt their own version. If you feel less confident about producing the complete build yourself, there are more than enough resources available online to help you create something flashy and bangy without the added smoke show.

Lucy Rogers Firecracker Raspberry Pi

For the physical build itself, Lucy used a plastic soft drink bottle, a paper plate, and plastic tubing. Once painted, they provided the body for her firecrackers, and the support needed to keep the LED NeoPixels in place. She also drilled holes into the main plastic tube that ran up the centre of the firecracker, allowing smoke to billow out at random points. More of that to come.

Lucy Rogers Firecracker Raspberry Pi

Spray paint and a touch of gold transform the pieces of plastic piping into firecrackers

The cracking, banging sounds play via a USB audio adapter due to complications between the NeoPixels and the audio jack. Lucy explains:

The audio settings need to be set in the Raspberry Pi’s configuration settings (raspi-config). I also used the Linux program ‘alsamixer’ to set the volume. The firecrackers sound file was made by Phil Andrew. I found that using the Node-RED ‘exec node’ calling the ‘mpg123’ program worked best.

Lucy states that the hacking of the e-cigarette was the hardest part of the build. For the smoke show itself, she reversed its recommended usage as follows:

On an electronic cigarette, if you blow down the air-intake hole (not the outlet hole from which you would normally inhale), smoke comes out of the outlet hole. I attached an aquarium pump to the air-intake hole and the firecracker pipe to the outlet, to make smoke on demand.

For the power, she gingerly hacked at the body with a pipe cutter before replacing the inner LiPo battery with a 30W isolated DC-DC converter, allowing for a safer power flow throughout the build (for “safer flow”, read “less likely to blow up the Raspberry Pi”).

Lucy Rogers internal workings Firecracker Raspberry Pi

The pump and e-cigarette fit snugly inside the painted bottle, while the Raspberry Pi remains outside

The project was partly inspired by Lucy’s work with Robin Hill Country Park. A how-to of that build can be seen below:

Although I won’t challenge you all to dismantle electric cigarettes, nor do I expect you to spend money on strobe lights, sensors, and other such peripherals, it would be great to see some other attempts at digital home fireworks. If you build, or have built, anything flashy and noisy, please share it in the comments below.

Photo credit: Lucy Rogers/IBM.


Oliver avatar

Nice project – if done with a little µC or max with an Arduino. Using a Raspi for that feels like running your browser on a Cray supercomputer… :-(

Richard avatar

But with a RPi you can add so much more to the project, build on her work.

For example you can synchronize with some music and visuals with the smoke.

Or you could make an ‘angry face cartoon head’ that uses vision detection to recognize the ‘other half’ and start the smoke coming from the ears. For the times when they (by which I mean me) don’t notice that they’ve done something wrong. :)

Dan Fryling avatar

I like it

Phil Spiegelhalter avatar

Safer alternative sources of the ‘smoke’ would be either:
a/ Steam engine smoke generators designed for Model Railway locos in gauges from 00/H0 through 0 and 1 to G Scale. Modern items such as those from Massoth are designed to emit smoke in PUFFS synchronised to (the loco’s wheels), and to work with 5V logic (other voltage models available). They could therefore be arrange to match the musical beat.
b/ Avoiding oil altogether – the ‘misters’ which use Ultrasonic transducers to vapourise water resulting in a low cloud over the pool of water. Often available with (underwater) coloured lights. – controlling the fan with something derived from the music/volume?

Andrew Marshall avatar

not sure I like the idea of the Ecigs thing….sort of sends the wrong message to children…. Am sure there better ways to produce the effects… But Ecigs???!!! this just seems very wrong to me…. Project it’s self is great idea just the implimentation is dubious…

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