For a while now I have been talking about hooking up the Emotiv headset brain computer interface (http://emotiv.com/) to the Pyrocardium and this Thursday we managed to pull it off.

What you see in this video is me in a headset actively trying to turn on the fire with my mind. You can tell I am trying to turn on the fire by when I am holding out my hand. I find using a gesture generally helps me focus on a very precise thought. The thought to turn on fire in this case was to imagine the look and sound of the fire and “will” the fire into existence using psychic energy coming out of my forehead. I realize the part about the forehead energy sounds a little flaky but the neat thing is that it works quantitatively better.

To get to this point, I trained the system to recognize the thought pattern for setting things on fire with my mind. This was done using software Emotiv distributes to developers. I took the output of this software, interpreted it some, and then wrote to the USB controller board that runs the Pyrocardium. And then fire happened!

A few other people (Wanda, Kurt, Zack, and Bash) were also able to try the headset and make fire with there thoughts. They seemed pretty pleased with the results. : )

Also, in the video is Zack spraying color fire stuff into the flame to turn it red. Neato!

Oh, and big thanks to Bash who brought the headset, software, and laptop that allowed all this to happen.

Ethan managed to turn fire a bright red color using strontium chloride salt dissolved in water. He dispensed the salt with an airbrush nozzle powered by a small air compressor and we tried on several flames including a large propane venturi flamethrower as shown in this video.

Hi-Def Version

A while back I posted about my first attempts to make a stethoscope amplifier as an input to PyroCardium.  This has worked well, though it has required some tweaking since then. First, it turned out that the resistor network used to power the electret mike and to bias the output signal to within the range of the single supply op-amp I’m using was too low resistance, and was substantially loading the relatively high impedance output of the electret. Secondly, getting a good seal between the microphone and the stethoscope tubing is critical for getting a decent signal out. Tweaking those things gave us a setup that worked pretty well for Alchemy and Maker Faire.

That said, there are some definite problems with our current stethoscope/microphone setup. First, it turns out it’s surprisingly hard to position the stethoscope on your chest to really pick up your heartbeat, especially as our current setup doesn’t have audio feedback so you can hear whether you’ve found it or not. Secondly, the stethoscope does a pretty good job of picking up ambient noise.  It works great it a quiet room but less well at a noisy, crowded event.  In fact I was able to get it to trigger on the beats of the music playing at Alchemy with just a little tweaking. This is great for some other things we have in mind for Priceless but less good for picking up your heartbeat.

So, we’d like to find a better system for Burning Man.  Ideally we’d like something where there’s no ambiguity about where to place the sensor and a sensor that robustly picks up your heartbeat, regardless of environmental noise, the fact that you’re running in place, or anything else.  So far we’ve had two ideas - use some kind of simple EKG system, or use a pulse oximeter.  This weekend I tried building this simple EKG circuit but met with no success whatsoever - all I could see at the output was 60 Hz line noise.  I’m not really sure why (the high common-mode rejection ratio of the instrumentation amp is supposed to take care of that) but I’m not sure I have the skill set to make it work.  I’m also not sure that this EKG system will be robust enough or easy enough to use on the playa, and there are also safety issues with hooking it up to a line powered system.

So, my current plan is to buy a cheap pulse oximeter and see if we can rip it apart and get it to interface to a PC.  If anyone out there reading this knows about pulse oximeters and how to do this let me know.  Also, if you’re good at analog design and want to make the ekg circuit work, that would be good too :).

Watch the video.

Reporter: “So then what application do you have, besides the entertainment factor?”

Brett: “Wait, what?”

Brendan: “OTHER than the entertainment factor? What are you talking about?”

Brett: “Don’t get me started on the transition between the sense of human curiosity–”


Reporter: “No no, that’s excellent–”

Brett: “To explore the physical properties of nature–”

Reporter: “Right, but don’t you have something like, it’ll replace rocket ships to go to the moon?”


Brendan: “No it’s more like, even on the moon people will need something fun to do… and slightly dangerous. It’s more along those lines.”

False Profit Labs is proud to bring The Hydrogen Economy and PyroCardium to Maker Faire. Especially now that our circuitboards work! The last few days have been a bit harrowing, since the first time we fired up all twenty of our the flame effects, we blew up our power supply. Kurt Thorn revisioned the electronics in 24 volts DC instead of the high-voltage AC line we were using and at 11:30pm last night PyroCardium came to life.

We’re jamming a lot of technology into this project of computer-controlled fire. The little sculpture is a prototype, with a 20-foot-tall spiral to follow for Burning Man in August. It has 16 flame effects, each a small propane venturi flame pipe with a solenoid valve. All the flames are fired individually by a USB-connected driver board controlled by a False Profit Labs software application that runs various flame algorithms. Each algorithm changes the response and patterns of the flame. And at Maker Faire on Saturday from 6-10pm you can place the PyroCardium stethoscope on your chest and see your heartbeat race up the sculpture in a spiral of flames.

PyroCardium’s first test-run