FireHero 3 is finally here! Originally built for a music festival, FireHero 3 was designed from the ground up to focus on putting on an incredible live show. Read on to see more pictures and details of the system!
And now for some info about the system itself!
FireHero 3 is rebuilt from the ground up. Some of the new features of this version include:
- A completely revamped fuel system capable of delivering almost 10 times the peak propane output of the previous versions.
- A new Silicon Nitride HSI-based ignition system.
- A custom-designed control system complete with an operator's panel, status displays, custom data exchange protocols, and solid-state switching of the solenoid valves.
- The increase of the normal five effects to six (to accommodate the guitar interface) and the addition of four 40-foot flame effects to the frame (not shown in the current video)
- The addition of two free-standing flame cannons, each capable of producing 100 foot flames.
A new control system was designed for FireHero 3, from the ground up. I developed a socket-based Ethernet communications protocol and client/server software using Python to exchange information between the control computer(s) and the Raspberry Pi-powered FireHero server. Commands are sent to a multithreaded server running on the Pi, which then controls an Arduino Mega over a 1,000,000 baud serial connection. Interesting note: I was having HUGE issues with note delay times until I bumped up the baud rate to 1,000,000 bps. The Arduino Mega then sends TTL signals to Solid State Relays (SSR), which in turn fire the solenoid valves on 120VAC. You'll notice that the Arduino Mega is sporting an Ethernet shield, which allows it to send back real-time status data of the system on request. A separate control computer pings the Arduino, which responds with the current status of the FireHero system. This includes effect states, current levels on each HSI, the HSI voltage reading, the pressure readings from the digital pressure transducers, and temperature readings from the main frame. All of this data is displayed on a custom GUI at the operator's panel. This software also performs automatic monitoring of the system, with built-in failsafes to initiate a system shutdown in the event of over-pressure or over-temperature readings, a current reading from an HSI that is below a certain threshold (which means that the HSI is dead or dying and un-ignited propane could soon be venting), and over-or-under voltage readings. Also integrated into the system are N.C. emergency stop perimeter switches, which instantly kill the power to the solenoid valves (which fail closed) and initiates a system-wide shutdown. Another interesting note: the operator's panel is protected by keyswitch and RFID, making it impossible for anyone unauthorized to boot up the system without the proper key and RFID tag.
Guitar MIDI interface:
Ever since the original FireHero system, it has been my goal to be able to interface it to live instruments.
With this version, it's now possible! I use a Roland GK-3 hexaphonic pickup, which is mounted to the guitar with double-sided tape and connected to a GI-20 pitch-to-MIDI converter. The MIDI output of the GI-20 is fed into custom Python software which analyzes the data stream and ultimately sends the output over Ethernet protocol to the FireHero-side computers, which output the patterns specified by the software. The Python host software is made up of a series of algorithms designed to perform intelligent chord-detection, as well as detect single notes and place them appropriately. The software memorizes all the chord progressions of a particular song as the guitarist plays in order to ensure consistent output for each chord.
It's a bit blurry, but this is the new main FireHero frame... of course, with a Christmas twist!
I use a closed-loop, thermostatically controlled water heating system to maintain the hot water bath that the supply tanks sit in and ensure adequate vaporization rates to keep up with propane demand.
Here you can see the two 100# main supply tanks in the water bath, with hoses going to the regulating assembly. The regulating assembly brings down the high pressure from the main tanks (typically around 120-200psi, depending on the temperature of the water bath) down to a constant 60psi. The regulator I have is only rated for 1,000,000 BTU/hr, and FireHero typically uses FAR more than a measly 1,000,000 BTU/hr. Thus, I have a regulator bypass valve built into the assembly. This allows me to temporarily bypass the regulator to open up the high pressure side directly to the low pressure side and help to quickly regain pressure after a massive cannon shot or a similar propane-hungry event. This type of manual control requires a lot of operator skill and attention to ensure that the system is always at an optimal pressure. You can also see the laptop that I use to control the system (I can now control everything through internet protocol, which means that I could theoretically play FireHero over WiFi from the comfort of my couch, or control it from any computer in the world that has an internet connection). Not shown in this picture is the main operator's control panel (darn, because it looks so cool all lit up!).
Testing valve #6.
A view from the back.
Propane enters the main vapor accumulation tank though the main LPG-rated supply hose, and I can monitor the pressure both manually through the analog gauge, and remotely through software by using the digital pressure transducers that are integrated into the system at various points in the fuel supply.
Here you can see the main fuel shutoff valve, which is a nice pneumatically-actuated 3/4" full bore ball valve. By feeding CO2 at around 100psi into the Namur solenoid valve mounted to the actuator body and remotely triggering the Namur solenoid through a Solid State Relay, I can effectively shut off the fuel supply remotely to the manifolds within mere seconds. This is just one of the new safety features that I designed into the system to make it suitable for public performances.
These are the main fuel distribution manifolds. They're machined out of solid Aluminum, and allow me to break out up 12 fuel connections via 1/4" ball seat fittings. The ball seat fittings allow me to make connections in seconds with no external sealing method required - no more gas teflon tape or pipe dope! Just an 1/8 turn with a wrench past hand-tight and the connection is complete and fully sealed.
The six main valves are quality STC valves with a 4mm orifice size, which is almost double the orifice size of the previous valves I used.
Here you can see the configuration of the six main flame effects. Propane gas is directed from the nozzle (welded to the frame) and across a Silicon Nitride Hot Surface Ignitor (HSI). 120 volts AC is passed through a variac and then into the bank of HSI's. The temperature of the HSI's is directly proportional to the voltage applied, and the variac is used not only to compensate for voltage drop, but to boost the temperature of the ignitors if needed. It also provides an easy way to slowly warm up the ignitors without blowing a breaker from all 12 powering up at once (sucking ~2.5A each on startup).
This is one of the two large flame cannons. These effects are easily capable of producing 100 foot flames, and boy are they loud! Propane vapor enters through a regulator and into a dedicated 20# accumulation tank. The size of the flame is directly related to the pressure setting of the regulator, so the size of the effects can easily by adjusted anywhere from 10-100+ feet. A single-acting pneumatically-actuated ball valve running off of CO2 is used to open a full 3/4" bore barrel and empty the entire tank in seconds. The output is directed past a standard Silicon Nitride HSI for ignition. So far I haven't had the chance to fire these at anything over 60psi, which produced a massive fireball and a sort of "sonic boom" which shook my chest and echoed around the mountains surrounding my house. The regulator and components are rated for up to 135psi, so there's still plenty of fun experimenting to do! I'd also like to begin experimenting with different nozzle shapes and sizes.