The Flaming Palm Trees

Overview

This summer I built two flaming palm trees with a Teensy control system. Why? To impress my friends mostly, and have a fun project I could bring with me to festivals and parties. The goals were for it to be reasonably safe and interactive.

The palm trees, or "fire poofers, " shoot fire into the air by opening solenoids that are connected to propane tanks. The pressurized propane ignites the pilot lights which are connected to a separate propane tank.

Here's my original drawing of how I wanted the project to look:

Building the plumbing:

Building a fire poofer involves high pressure propane. I shouldn't even need to say that that has the potential to be extremely dangerous.

These are the best resources for learning how to build your own fire poofers. Seriously, please take the Flame Effects for the Artist workshop before building any projects involving high pressure fuel.

• The book "Make Fire" by Tim Deagan has amazingly detailed instructions and great information about the safety and science of working with propane.
• The "Flame Effects for the Artist" workshop by Eric Smith and Lynn Gamroth.
• The book "The Practical Pyromaniac" by William Gurstelle. Despite the name, it's more history and science textbook than guide for making things, but it has some good tidbits for making fire hidden among the history lessons.

If you haven't built fire art before, I recommend starting with a low pressure system, like this simple ruben's tube.

A diagram of the plumbingthat I used is below.

As you can see from the close-up, when the ball valve is open and the solenoid is closed, propane gas from the propane tank fills the accumulator and becomes pressurized.

When the solenoid is open, the pressurized propane ejects from the top of the metal tube, and through the lit pilot light at the top, causing a burst of flame.

Where should you get fittings?

You won't be able to find many of these products available at your local hardware store. I recommend poofersupply.com for hoses, regulators and solenoids. McMaster Carr has free next day shipping in the US and supplies every fitting imaginable. Just like any other plumbing project, it will probably take you 3 or more "shopping trips" before you have the right parts.

Don't try to save money! I bought this inexpensive solenoid from Amazon, and it ended up having a lot of problems. If there was too much pressure, it would freeze up and stop working.

If you want to display your fire art anywhere you'll have to be familiar with the fire code of the state where you're displaying your art, and build everything to code. You will also need to provide proof that each fitting in your piece is up to code (usually the pressure and LP gas rating is stamped in the metal, but if it's not you should save your bill of sale). Selecting valves with high pressure ratings means that it will be extra safe, and also that you'll be able to show off your work in places with strict regulations.

Watch this video for a brief overview of how we created the plumbing:

Testing the plumbing:

First, always test your plumbing for leaks using a spray bottle with soapy water (demoed in the video above).

I wired up the the solenoid and tested it by touching the solenoid to 12V battery terminals. It clicked open and closed.

The next step was to wire up a basic button (also demoed in the video above).

Finally, I added a teensy and some basic code to open and close the solenoid.

const int buttonPin = 2;     // the number of the pushbutton pin
const int testLED =  13;      // the number of the LED pin
const byte solenoid = 6; 
// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status
void setup() {
 // initialize the LED pin as an output:
 pinMode(testLED, OUTPUT);
 pinMode(solenoid, OUTPUT);    
 // initialize the pushbutton pin as an input:
 pinMode(buttonPin, INPUT_PULLUP);
}
void loop() {
 // read the state of the pushbutton value:
 buttonState = digitalRead(buttonPin);
 // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
 if (buttonState == HIGH) {
   // turn LED on:
   digitalWrite(testLED, HIGH);
   digitalWrite(solenoid, LOW); //closes solenoid 
 } else {
   // turn LED off:
   digitalWrite(testLED, LOW);
   digitalWrite(solenoid, HIGH); //opens solenoid 
 }
}

That all worked, so it was time to move on to making a more complex control system. My friend Paul has a laser cutter, and he had laser cut a beautiful control box from a design that I sent him. It has 5 arcade buttons, two of which are the light up kind (the two in the corners).

To make use of this awesome control system, I needed to write some cool patterns for the fire. If you do it right, the poofs can sound like music, or like the palm trees are talking to each other in a burble of fire. Last year I got to write the code for a piece called the three wishes, and I realized that nothing beats writing code to controls fire.

I'm writing a series of tutorials with the code nitty gritty, called "Intermediate Arduino programming with Fire" but until then, the github with the final patterns is linked at the bottom. PalmTreePoofer has the fire patterns.

Building the structure:

I'm proud to say that the structure was build from 80% recycled metal. The sides are made of aluminum vents, which I cut into strips and attached to 10 foot aluminum poles with metal screws. Even the fronds are made of recycled hardware cloth zip tied to recycled thin metal poles.

The only parts that wasn't recycled was the steel for the base and top.

The piece needed to be sturdy so it wouldn't blow over in high winds. The base pieces were screwed onto a steel plate on the bottom, and screwed onto round steel plates at the top. I originally designed the steel pieces to be cut out on an industrial CNC, but in the end I decided to save $400, and ended up drilling the holes it by hand and cutting the pieces into circles on my neighbor's router.

Adding the LEDs:

Each of the 12 leaves had to be hand-soldered. Somebody needs to invent some kind of bedazzler/solder gun that will solder wires onto a cut LED strip with the click of a button. Bonus points if it automatically adds heat shrink.

After setting up the structure outside, some of the LEDs seemed to not be getting enough power, and a couple of the palm tree fronds weren't lighting up (I'm guessing this is from dragging the trees through the gravel on my driveway). I went through and re-soldered some of the joints that were problematic.

Since I spent so much time soldering the LEDs, my goal is for them to last a long time. Because of that, I used some techniques that I've shared in my tutorial "Making large LED projects."

At the last minute, I realized that I'd forgotten to get anything to diffuse the LEDs. Thankfully, when the LEDs were covered with a fine layer of dust, they looked beautiful.

What's next?

For an added layer of safety, I am going to build and add these flame sensors to both poofers, based on Paul's blog.

https://www.pjrc.com/pilot-light-flame-sensor-for-burning-man-art/