Watching the Lunar New Year celebrations last month, I began to think about our love of loud bangs and bright flashes. However, fireworks – such as small explosive firecrackers – have proved to be so dangerous they are banned in many countries, including the UK.
So I decided to make some firecrackers for myself – but ones that are legal and safe!
The firecracker idea
Make some ‘fake’ decorative firecrackers from plastic plumbing pipe. Attach some very bright LEDs or neopixels. Control the lights with a Raspberry Pi using Node-RED. Turn up the volume on a speaker and play ‘cracking’ sounds through it. And then add smoke from an electronic cigarette into the mix.
All triggered by a switch.
This blog is intended as a rough guide to what I did – it’s not a step-by-step instruction manual.
The total build cost was about £185 (parts listed at the end) – however, I am sure some savings could be made.
The E-cigarette in particular was fiddly to hack and each one will be different. However, you are welcome to take this idea and adapt it for your own use.
I’d love to hear what you make – let me know in the comments below.
This project uses a Raspberry Pi 3 to control everything, programmed using a Node-RED flow. I used pre-installed nodes, plus the Neopixel node. The complete flow is available on GitHub.
Some soldering was required in this project. The LED lights are WS2812B neopixels controlled via a 3V3 (3.3 Volts) to 5V level shifter.
For sound I use a USB audio adapter and a portable speaker. This is because there is a conflict between the neopixels and the normal audio jack. For the smoke, I hacked an e-cigarette and used glycerine, rather than a nicotine solution. I use an aquarium pump to force the smoke out of the e-cigarette and up the tube. These are both powered by a 30W Isolated DC-DC Converter. MOSFETs switch the e-cigarette and the pump.
A button attached to the GPIO pins triggers the firecrackers. However, I am tempted to trigger it from a motion sensor to make visitors jump.
The rest of the props are made out of things I had around – a two-litre fizzy water bottle, gold ribbon, a paper plate, plastic pipe and spray paint.
Adafruit NeoPixel Digital RGB LED Strip – Black 30 LED – BLACK: You thought it couldn’t get better than our world-famous 32-LED-per-meter Digital LED strip but we will prove you wrong! These NeoPixel strips have 30 digitally-addressable pixel LEDs per meter and are very affordable and are only 12.5 mm wide, 10 mm if you remove the strip from the casing. Read more.
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