ESP8266 Powered Propane Poofer
Nick Poole 
Flame Throwing 101
Propane poofers are a comprehensively solved engineering problem. A quick Google search reveals more designs for propane-powered flame effects than you can shake a stick at. It also becomes apparent, in short order, that the Burning Man festival attracts quite the collection of semi-professional pyros. Browsing these designs, I've found that while there are a lot of variations, the basic structure of a propane poofer stays fairly constant:
This is the go-to design for propane flame-cannons, the so-called "accumulator cannon". In an accumulator cannon, a fuel source is regulated to a relatively low pressure and fed into accumulator tanks (often, they're modified propane cylinders). These accumulators allow several cannons to be fed from one large gas source. Each cannon has a pilot on a low pressure regulator which burns constantly to provide a source of ignition when it's time to make a fireball. When the time comes, the solenoid valve at the end of the accumulator is opened, allowing the accumulator to empty through the barrel and be ignited by the pilot. Because the accumulator was allowed to pressurize, you can fire multiple accumulator cannons on the same tank simultaneously without worrying about a big pressure drop in the system.
Because I was building a single portable cannon, I decided to modify this design a little bit. Here's what I came up with:
My fuel source would be a pair of disposable propane cylinders, like the kind used in camping stoves and torches. These are small, lightweight and inexpensive... plus, I could buy them by the armful at my local hardware supply. Two such tanks would feed my cannon. Once I had decided on the gist of my design, I started shopping for parts...