DEF CON 34 BCCC: Beer Chilling Goes Rogue

 

On an overcast afternoon in April, I found myself handing off a strange piece of equipment to be trucked to Las Vegas. It came into my possession in a bankruptcy that still shocks people. And it was the cornerstone of a contraption that won the Murder Hobos a spot on the podium of DEF CON's most unpredictable hardware event, the Beer* Chilling Contraption Contest.

In its 21st year, Beer Chilling has a long history as a sideshow and contest at DEF CON in Las Vegas. Others have recounted the full history better than I can. The rules are simple: Cool a beverage from some high temperature to some lower temperature. Measure how long it takes to do that. Don't mess up the beer. Get a score, iterate, and improve. The quirkiness and creativity keeps me coming back as a spectator and contestant. The organizers stock tables with supplies for the Hacked bracket. People can build and compete entirely with on-site materials and the help of incredible volunteers. But the kookiest ideas are reserved for the Unlimited segment where people bring their contraptions from miles around to compete. tinribs and melody-rs, parent-child team members of the Murder Hobos have stuck their toe in the water with Hacked devices at previous years. This year, they had an eye on a design for Unlimited, and I helped acquire some key components. This serendipitous acquisition would allow the three of us to make a proper run at the no holds barred contraption melee.

In November 2025, news broke that Rogue Ales was bankrupt. A fixture of PNW craft brewing would be broken up and auctioned off out of their brewery/warehouse on the harbor in Newport, OR. While browsing the auction site, tinribs lit upon the lab's dusty PolyScience circulating chiller which retails for over $5000 brand new. It works by running a compressor for cooling in tandem with a heater for precise temperature control via sensors with a tolerance of .01C! One could place an object within the body to chill it, or you could pipe the chiller liquid out of the chiller for cooling outside the unit. He had always wanted one for Homebrew that he brings every year to Toxic BBQ, but BCCC gave him an even better one. A $250 YOLO bid and a week of nail-biting later, it was his. The only problem was it was 1000 miles away from home.

Enter me. I jetted down from Portland metro the next weekend and picked it up, and he made his way to me in April 2026 for the exchange by car. Before he left home, I tested it and found that, barring a slow coolant leak, it still worked just fine. Whew. With a device whose pedigree with Rogue Ales could not be denied, the chiller was going to be the cornerstone of our Beer Chilling Contraption for 2026.

The hard part would be turning serendipity into success. We couldn't just show up with a commercial chiller. It needed to be contraption. tinribs got to work. He had acquired two big dispenser plates from soda vending machines. And a 3D printer board could be a control head. But the chiller allowed the entire contraption to be fully regenerative: only electricity, not ice, dry ice, liquid nitrogen, or any other substance, would be needed to cool it down and make another run. The design eventually morphed into the following stack of components:

• Control Head: 
• 3D Printed Peristaltic Pump
• 3D Printer Board running Marlin
• Stepper Motor
• Raspberry Pi
• Thermistors 
• Thermal Battery: 
• Cooler
• Soda Machine Dispenser Cooling Plates
• Phase Change Material coolant packs
• Regenerative Loop: 
• PolyScience Circulating Chiller
• Plenty of tubes and other fittings

Behold! The Machine!

  

The cycle design looked something like this: 

1. The chiller cools the battery to a certain low temperature.
2. The control head pumps the beverage into the battery.
3. The battery cools the liquid (without freezing it!)
4. And the chiller restores the battery to equilibrium for the next run.

A host of tweaks followed. In testing, the deep freeze -20C PCM packs had to be swapped out for less-aggressive -8C versions. An alcohol rinse was added to ensure all water was purged after a run. The final settings were dialed in with a control page that not only accepted settings values but also displayed sensor history. We calibrated the machine the day before with 5% alcohol solutions carbonated with a Sodastream and microwaved to 100F/38C. This was fast and it avoided sugar and other contaminants accumulating in the lines. All of tinribs and melody-rs' hard work and testing was about to pay off.

On the day of, we hit the contest floor and felt the energy. The booth was crowded and covered in buckets of water and ice, dry ice fog, and discarded beverage containers from runs past. Fire marshal violations were posted proudly on the most dangerous-looking devices (while making it clear all violations had been remediated). Eager contest goers were still experimenting as the clock ticked down. Each team got three runs, and everyone was using each to the fullest.

The contest runners greeted us with amazement. This was a contraption in the real sense of the word. We found electrical power and waited for the battery to come to temp: 2.5C. The 110F/43C car ride 45 minutes from home had done its worst, and our late arrival compounded the time pressure. After 45 minutes, we were coming down to the wire.

While we waited, I explained the machine to the curious (plenty of those at DEF CON) and tinribs set up the control head. I bought Bud Lightbeer's BCCC SAO. This is an official temperature keeping device for the contest, and it runs off an electronic badge! tinribs hit a snag with the awful DEF CON wifi. The open network is never reliable, but we thought it might afford us at least token access to a simple web server. Deauth packets were being more annoying than usual, and we couldn't maintain a connection for longer than 20 seconds. We broke out the backup screen and keyboard. Always bet on a hard line.

The run went down smoothly. A hot beer was pulled from a bucket being kept at 100F by a sous vide stick. The Hacked bracket hosted an impressive 920W run from a can shaken in an ice bath. Q, a research chemist, looked on as we made our attempt.  There was some struggle to deliver a proper beer without foam to match our calibrated liquid volume. We got 330g of Bud Light at 97F, the timer started, and the drink disappeared down the 3D printed receptacle as the pump whirred to life. 1'06" later, we measured a cool 34.7F. We came in second overall and sat atop the Unlimited bracket with over 850W of power sucked out of the drink in that time. Because of our battery regen time, we could not attempt a second run, but we were not complaining.

  

The BCCC might not look like something that would thrive at DEF CON. Chemistry, specific heat, phase changes, tubing, and liquid sensors aren't standard features of many computer conventions. But observing the people that are drawn here makes it click: A team of kids was chilling soda with their parents by pouring from bucket to bucket. The all-women team Eutectic Point flew their ice-bath heat exchanger from across the country to compete. And we all shared a love of creating something that we could explain and improve.

I was not a primary designer or tester on the contraption this year, and I appreciate being able to ride along with tinribs and melody-rs and take to the contest stage in victory once more. Many thanks to them, the other contestants, Rogue Ales for allowing us to salvage something from their demise, and the wonderful contest volunteers, especially the few veterans returning for the first time in a long time. Next year, the BCCC promises us more: ice, dry ice, and equipment to try. And we promise to bring it with a pit crew's practice, and maybe a few more tricks up our sleeves to drop our time and raise our wattage.

* Note: The BCCC is now 21, and it can drink. It was known by Beverage Chilling Contraption Contest in the past!

The Internet at DEF CON 33 (and BOM to make your very own)

 And it came to pass that the Pope of the Church of Wi-fi, yeah, even Renderman, didst bless and consecrate The Internet in this the 2025th year of the common era (and 35 years after Tim Berners-Lee invented it) on August 8th, the second night of DEF CON 33.

And lo, DuncanYoudaho didst capture the consecration thereof in an image. In the self-same breath as the consecration, the Pope did also pronounce a holy quest upon him as a teacher doth chastise the student that readeth not the book but kind of fumbles through the book report anyway.

Yeah, he was admonished with much reproachment to not share the graven image of the consecration until such time as the quest was fulfilled. That all the world wouldst see and hear and follow in the path. And this was the quest:

"DuncanYoudaho, if ye be a loyal servant of The Internet, teach those who see the image of this blessing how they also might obtain an Internet of their very own. Yeah, promulgate and proclaim the BOM that thou didst fulfill when making The Internet."

And so if thou wisheth to make this Thine Internet, obtain the shards of circuitry, and resistors, and switches, and hookup wire, and make ye an earthly copy of what is now The Blessed Internet!

Instructables

I made The Internet thanks to a great Instructable. The parts list has atrophied a bit with time, so I’m reproducing a BOM here with more modern selections. When in doubt, they’ve probably got better step by step instructions, so head there. What I did not do (and wish I did) is take the advice to make curly LED hookups and stand-offs.  Making the wires as tight as they are has lead to almost every solder joint breaking. The Internet has required constant maintenance which various users have graciously done and received stickers in return, most recently, Chip from Aviation Hacking Village.

Parts List

• Hammond 1591XX Series enclosure in a chosen size (Mouser/Digikey) or a similar looking enclosure - The plastic enclosure of The Internet uses a Radio Shack ABS project box. As these are no longer available in large quantities, I found a similar project box in the Hammond 1591XX Series enclosures.  These come in black, have a detachable bottom with rounded exterior edges, and come with PCB mounting holes inside the case for easy attachment of the strip board components.
• Red LED inside chrome-plated enclosure (Mouser/Digikey) - Pay particular attention to the voltage. Higher voltage LEDs will need more batteries.
• NE555 Timer (Mouser/Digikey) - The through-hole TI model is linked here. This is the grand-daddy of them all. The IC that birthed all other blinky lights. Kneel and say thanks. And provide at least 4.5V to power it.
• Resistors: 330Ohm, 2x 1M Ohm - The 330Ohm resistor can be changed to tune the blink to your liking.
• Battery Holder(s) for at least 6V power. 
• Hook-up Wire, Solid Core.
• Strip Board sufficient for mounting the components and attaching inside the case.

Equipment

• Wire Strippers
• Soldering Iron and Solder
• Double-sided Tape
• Screw Driver for case and PCB Screws

Steps

• Get circuit working on Strip Board or Bread Board.
• Cut 8mm hole in case for light
• Cut hole in case for switch. I put mine on the side of the box 
• Make stand-offs and long curly q's for LED, switch, and batteries
• Make final solder joints to hook everything up
• TEST IT 
• Screw down the Strip board to the box
• Affix the batteries to the strip board (I had to wire the 4x AA holder down as it kept breaking loose)
• Close it all up and test it again
• Get it demagnetized by the Elders of the Internet, or find another Pope of the Church of Wi-fi to bless it for you. 

Pinout stolen from NE555P Datasheet

 

Circuit Design

 

Pictures of The Internet

 

And the Lord did grin...

Currently, The Internet was handed off to members of DC404 for an East Coast Adventure. If Flat Stanley returns to DEF CON 34, I'm sure it will come with plenty of stickers. 

The Legend of the Murder Hobos

Spoiler alert: The real prize is friendship.

At R00tz Asylum, an official DEF CON event for kids, Facebook’s security team was running a CTF. The scene matched most rooms at DEF CON: intense staring at screens, poking at punny challenges, and no one really talking to each other. We chatted up our neighbors, Sodapop and p0wnyb0y about the con, the badge, and the contest. We realized the organizers encouraged teams, but no one else was talking. Pooling our resources, a 7 and 9 year old shot to the top of the leaderboard and took home the prize: 2 Chromebooks, and a con-friendship.

A chat at Toxic BBQ in 2018 lead to another team-up. Tinribs and I were Vegas locals looking to change up our DEF CON experience.  We took on the inaugural Dungeons@DEFCON with our 12 year old kids. Styled as the Murder Hobos, we won the Psychoholics-lead, D&D themed, CTF-style classic crypto challenge through cooperation, luck, and shenanigans, and we came away with the win and a black badge for our team of four. As far as we can tell, the kids are the youngest black badge holders in history. Grifter commented to The Dark Tangent during closing ceremonies, “What I like about a couple of kids winning a black badge is how much it’s going to cost Jeff. For life, baby!”

But we had a problem: only 4 of the 6 Hobos had a black badge, and so the next chase began. The very next year, family obligations took me away from DEF CON, so the Murder Hobos stormed Dungeons@DEFCON again but fell to the inimitable Fellowship of the Token Ring. Post-Covid, another run at D@D (with FOTTR contributing puzzles and CrookedFingers our Dungeon Master) ended with a second place finish. FOTTR decided to host their own contest, and Spy v Spy was born. With a thrilling finish, CamelCase bested the Murder Hobos by unlocking the dead drop minutes before P0wnyb0y arrived. Victory was elusive, but we couldn’t give up.

At DEF CON 33, I was trying to play it cool and relax. When we absorbed ourselves in a contest, we’d look up on Sunday afternoon at closing wondering where the weekend had gone. I was thinking I should take it easy. But it was not to be so. Spy v Spy had returned, and it had a compelling hook: souvenir slabbed playing cards when you completed incremental challenges. Sodapop and P0wnyb0y registered right away, and we were at the top of the leader board the most of the con. We cracked crypto, fabricated loaded dice with other teams, and chased dead drops for two days.

When the final round started, we made the cut, but didn’t know what we were up against. It was rumored one team had 12 people! So we unwrapped the challenge code book and got cracking. Sat at the disused Warlock Gamez booth, we were right in the walkway and kept getting interlocutors asking what we we’re working on (some of whom, we found out later, were actual spies from other teams), and they got a gruff reply. It was serious. Tinribs and Sodapop cracked numbers stations, P0wnyb0y decoded RTTY, and we found the spy. The final answer was phoned in over Discord while I walked back from the other end of the conference.

As I approached, I saw a confluence of people around the contest table. Tinribs was walking towards me shaking his head.

“Too late, we were a minute too late.”

Crestfallen.

“Just kidding. We got it.”

Elation. Joy. I screamed several expletives at him.

Around table was an excited mix of teams and organizers asking about clues and solves, tips and congratulations. Fox from the Whiskey Pirates may have teared up a bit, but so did we.

These contests and conferences are largely excuses. To get us off screens and in front of each other. Make friends and build community. Share skills that are weird and unique and unavailable in any concentration. Sometimes through competition, but also cooperation and conversation. With the win in hand, there was one final question.

The news came the next day: be at the main stage at 3pm. Victory, finally, after a 6-year chase, the Hobos all had black badges. After a whirlwind weekend, we were back on the main stage. None of the kids are children anymore. But we’re already planning our next escapade rather than retirement. FOTTR wants us to make our own contest. And I really want to share how we got here again. And maybe hang out with other puzzlers outside of one weekend per summer.

Cheers,

DuncanYoudaho

New Year, New DEF CON

During the DEF CON 26 DC101 Panel, someone (probably highwiz) asked one of the n00bs they brought on-stage, "What makes you a hacker?" In the past, it has been used by bad actors as an aggressive question.  Thoughtful types and artists have used it as a prompt.  But here it was dripping with curiosity.  "Why do you go to DEF CON?"

I'm more than a year out from a move that took me far from my hometown of Las Vegas to an adventure into the Pacific Northwest.  Budgets, family and time being what they are, I too had to ask myself, "What makes you a hacker?  Why should you go to DEF CON, again?"  Obviously, moving two states makes it harder to go.  Plane tickets are cheap enough in cattle-class, and I'm lucky to have family and friends in town upon which I can rely for lodging.  But family illness and obligation are also considerations, and this feeling in the pit of my stomach topped it all off: the idea that I no longer belonged.

Ironically, this security-focused community is affected by deep insecurities.  Concerns of legitimacy, competence, and belonging haunt us collectively, as do public examples of snake oil, burnout, and depression.  Discussions of Impostor's Syndrome are almost cliche in their frequency.  As is the mouth-agape disbelief following one of our rock stars admitting they second-guess themselves.  This loose band of social misfits and punks emerged from in our cocoon of BBSes and IRC to be famously dysfunctional. We have had to exorcise #MeToo demons, and our unhealthy relationship with alcohol keeps many away for fear of their own safety.  As a late-comer to DEF CON, I have not been personally affected by loss of friends in the community, but there's a reason Amber Baldet gave a talk on Suicide Interventions at DC21.  Hackers in my cohort are maturing as well.  Some of us are on their third career since the demoscene, and it has veered wildly away from any Information Security role.  There has to be something that keeps us coming back to the desert in August.  It sure ain't the unmistakable fragrance of Sunday morning talks.

It is a bit of a balancing act to maintain a conference that keeps drawing more and more people.  As of this writing, DC28 is scheduled to use almost 400,000 sq. ft. of conference space in a brand new facility.  Almost 30 villages with both broad and niche topics have formed, and each is a mini-con in and of itself.  Along with this widening scope, there were public and repeated attempts by The Dark Tangent to reestablish DEF CON as a Hacker event and set it apart from the Information Security industry where so many of its attendees find employment.  In the past, DT has publicly disinvited the Feds, and the run-up to DC27 saw another public clarification that while individual villages arrange their own sponsorship, DEF CON maintains no corporate sponsors.  You can see the push and pull of "What makes you a hacker?" at the highest levels.

And so we approach a new year and a new DEF CON.  Since DC19, I've grown with the conference.  I started managing Toxic BBQ with the help of friends and this will be our fifth consecutive kick-off barbecue.  People just show up to create an inviting space from scratch for anyone that can find it.  I won a Black Badge with my son at DC 26 by solving crypto puzzles and have tried to contribute in equal measure since then. And yet there's this nagging feeling...

Ultimately, I've decided the gate-keeping question is not an important one to answer.  What I give to and get from DEF CON keeps me going.  I'm comes down to a desire to think things I have never thought before.  I may not be able to show off like some, but I can gawk with the best of them at the Hacker Carnival.  DC28's theme, Discovery!, is right out of my high school years when the internet promised the sum-total of human knowledge at our fingertips and all that we could do once those barriers dropped.  Maybe we can celebrate by shedding our insecurities.  Just for the weekend.

Dan Moves North

Plenty has gone on in the past year. Here's a quick rundown:

- Learned how to quilt. 104 patches from my tour-guiding days on a lap quilt.

- Learned how to Black Badge at DEF CON 26. Shout out to my fellow Murder Hobos, PunkAB, and the entire Dungeons@DEFCON team for this kick-ass experience.

- Learned how to move across country through forest fires and with cats

- Learned how to survive a leg infection possibly from a cat scratch (not pictured; it was pretty gnarly)

- Learned how to not buy board games. I finished a 10x10 (play ten games ten times or more) without buying any new games in between. Moving thinned the collection, but it still takes up an entire linen closet.

Wristband Teardown from Amazon's #FireTVSDCC Event at San Diego Comic Con

A friend returned from San Diego Comic Con 2018 with an RFID bracelet used to track users in the Amazon Fire TV experience (on Twitter, #FireTVSDCC).  This is a teardown of the bracelet after the event.  At this time, I was unable to read from the bracelet.

The bracelet is fairly simple with a cloth band and plastic/paper tab threaded through.  The closure is plastic and one-way.  It bites into and mangles the cloth band if you attempt to remove, but you could probably shim it with tools and practice.  Might be a fun thing for the Tamper Evident Village if it turned out events were trying to use this for access control like plastic self-destructing wristbands.

The back contains a serial number.  I would like to see if this serial number would match the data read off the tag.

Separating the badge by prying them apart, I  spot the prize: an adhesive RFID tag placed between the glossy plastic covers.  It appears to have a model number of "CXJ-040" in the center of the tag.  It uses a circular antenna.  CXJ is the initials of Shenzen manufacturer Chuangxinjia.  Their product pages show many similar wristbands in a few different frequencies.

The tag didn't respond to my Android phone, so it is not a Mifare or similar.  Hopefully I can find a reader at the local Hackerspace or DEF CON 26.

Quotes from Dan Kaminsky's Keynote at DEF CON China

Above is Dan Kaminsky's keynote at the inaugural DEF CON China.  It was nominally about Spectre and Meltdown, and I thought it was immediately applicable to testing at all levels.  Here are some moments that jumped out at me:

On Context:

"There's a problem where we talk about hacking in terms of only software...What does hacking look like when it has nothing to do with software." 1:55

"But let's keep digging." Throughout, but especially 5:40

"Actual physics encourages 60 frames per second. I did not expect to find anything close to this when I started digging into the number 60...This might be correct, this might not be. And that is a part of hacking too." 6:10

"Stay intellectually honest as go through these deep dives. Understand really you are operating from ignorance. That's actually your strong point. You don't know why the thing is doing what it is doing...Have some humility as you explore, but also explore." 7:40

"We really really do not like having microprocessor flaws...and so we make sure where the right bits come in, the right bits come out. Time has not been part of the equation...Security [re: Specter/Meltdown] has been made to depend on an undefined element. Context matters." 15:00

"Are two computers doing the same thing?...There is not a right answer to that. There is no one context. A huge amount of what we do in hacking...is we play contexts of one another." 17:50

[Re: Spectre and Meltdown] "These attackers changed time which in this context is not defined to exist...Fast and slow...means nothing to the chip but it means everything to the users, to the administrators, to the security models..." 21:00

"Look for things people think don't matter. Look for the flawed assumptions...between how people think the system works and how it actually does." 35:00

"People think bug finding is purely a technical task. It is not because you are playing with people's assumptions...Understand the source and you'll find the destination." 37:05

"Our hardest problems in Security require alignment between how we build systems, and how we verify them. And our best solutions in technology require understanding the past, how we got here." 59:50

On Faulty Assumptions:

"[Example of clocks running slow because power was not 60Hz] You could get cheap, and just use whatever is coming out of the wall, and assume it will never change. Just because you can doesn't mean you should...We'll just get it from the upstream." 4:15

"[Re: Spectre and Meltdown] We turned a stability boundary into a security boundary and hoped it would work. Spoiler alert: it did not work." 18:40

"We hope the design of our interesting architectures mean when we switch from one context to another, nothing is left over...[but] if you want two security domains, get two computers. You can do that. Computers are small now. [Extensive geeking out about tiny computers]" 23:10

"[RIM] made a really compelling argument that the iPhone was totally impossible, and their argument was incredibly compelling until the moment that Steve Jobs dropped an iPhone on the table..." 25:50

"If you don't care if your work affects the [other people working on the system], you're going to crash." 37:30

"What happens when you define your constraints incorrectly?... Vulnerabilities. ...At best, you get the wrong answer. Most commonly, you get undefined behavior which in the presence of hacking becomes redefinable behavior." 41:35

"It's important to realize that we are loosening the assumption that the developer knows what the system is supposed to do...Everyone who touches the computer is a little bit ignorant." 45:20

On Heuristics

"When you say the same thing, but you say it in a different time, sometimes you're not saying the same thing." 9:10

"Hackers are actually pretty well-behaved. When hackers crash code...it does really controlled things...changing smaller things from the computer's perspective that are bigger things from a human's perspective." 20:25

"Bugs aren't random because their sources aren't random." 35:25

"Hackers aren't modeling code...hackers are modeling the developers and thinking, 'What did [they] screw up?' [I would ask a team to] tell me how you think your system works...I would listen to what they didn't talk about. That was always where my first bugs came from." 35:45

On Bug Advocacy

"In twenty years...I have never seen stupid moralization fix anything...We're engineers. Sometimes things are going to fail." 10:30

"We have patched everything in case there's a security boundary. That doesn't actually mean there's a security boundary." 28:10

"Build your boundaries to what the actual security model is...Security that doesn't care about the rest of IT, is security that grows increasingly irrelevant." 33:20

"We're not, as hackers, able to break things. We're able to redefine them so they can't be broken in the first place." 59:25

On Automation

"The theorem provers didn't fail when they showed no leakage of information between contexts because the right bits went to the right places They just weren't being asked to prove these particular elements." 18:25

"All of our tools are incomplete. All of our tools are blind" 46:20

"Having kind of a fakey root environment seems weird, but it's kind of what we're doing with VMs, it's what we're doing with containers." 53:20

On Testing in the SDLC

"We do have cultural elements that block the integration of forward and reverse [engineering], and the primary thing we seem to do wrong is that we have aggressively separated development and testing, and it's biting us." 38:20

"[Re Penetration Testing]: Testing is the important part of that phrase. We are a specific branch of testers that gets on cooler stages...Testing shouldn't be split off, but it kinda has been." 38:50

Ctd. "Testing shouldn't be split off, but it kinda has to have been because people, when they write code, tend to see that code for what it's supposed to be. And as a tester, you're trying to see it for what it really is. These are two different things." 39:05

"[D]evelopers, who already have a problem psychologically of only seeing what their code is supposed do, are also isolated from all the software that would tell them [otherwise]. Anything that's too testy goes to the test people." 39:30

"[Re: PyAnnotate by @Dropbox] 'This is the thing you don't do. Only the developer is allowed to touch the code.' That is an unnecessary constraint." 43:25

"If I'm using an open source platform, why can't I see the source every time something crashes? ...show me the source code that's crashing...It's lovely." 47:20

"We should not be separating Development and Testing... Computers are capable of magic, and we're just trying to make them our magic..." 59:35

Misc

"Branch Prediction: because we didn't have the words Machine Learning yet. Prediction and learning, of course they're linked. Kind of obvious in retrospect." 27:55

"Usually when you give people who are just learning computing root access, the first thing they do is totally destroy their computer." 53:40 #DontHaveKids

"You can have a talent bar for users (N.B.: sliding scale of computer capability) or you can make it really easy to fix stuff." 55:10 #HelpDesk

"[Re: Ransomware] Why is it possible to have all our data deleted all at once? Who is this a feature for?!... We have too many people able to break stuff." 58:25

A) Original Twitter Thread
B) Thread Unroll from @threadunrollapp

The Glowhawk: OFBC Gaiden

Update: Plume added, rebuilt using thread and pipe cleaners to keep it upright and separate strands, removed plasticard sticks and zip ties.  Also pulled the EL Wire which is being repurposed in my son's EL Hoodie.

We were only able to print a few OFBC 2.0 cases before DEFCON 26. The leftover parts would have sat in my toolbox for quite a while if not for a serendipitous mistake: I ordered the wrong color LEDs from Sparkfun. This plus a little construction advice from a seamstress helped me cobble together the glowing headgear that is The Glowhawk

My courage and thinning hair prevents me from getting a mohawk while at DEFCON, but I've always wanted one. Instead I started to create one with a networking theme. Pipe cleaners in the color of Cat6 twisted pair served as a thick mane anyone could be proud of. This was wired onto a hat as a test. It looked OK, but it was kind of stubby to wear all on its own.

The LED driver for the OFBC is overdone. A single charge can last 10 hours on the original model. I wondered how much it could handle in terms of output, and a little breadboarding showed me I could wire several of the LED modules together as long as they were in parallel. Now how to use them?

The LEDs are these 3W green modules with attached heat sink. Direct eye contact is not recommended (hence the pains we took to use momentary buttons on the OFBC). On the beer light, we diffused the over-bright light so it could be sculpted by the drink it passed through. I was inspired by a fiber optic dress I saw elsewhere and found fiber optic table centrepieces for dirt cheap on Amazon. Some hot glue joined the disassembled fiber optics to the bright LED. The mane of glowing green was born!

With this fresh take in hand, DEFCON was upon us. I packed my things and thought I might take a crack in the evening. The Richard Cheese show was the perfect venue to solder everything together. The_bozo and I found a better place to work where the hot glue gun could run safely. I transferred the existing Cat6 mohawk to a bright green John Cena hat from Goodwill. Inside the channel that ran between upturned pipe cleaners, I hot glued the modules and fiber optics. Zip ties kept the fiber bundles from flopping around too much.

I consider the Glowhawk a great success, if a tad impractical. It lasted about 2 hours on a charge, and I was able to walk around wearing it with the mobile party crew for that long before it got uncomfortable.  A photo of me wearing it hit the DEFCON Closing Ceremonies, and my son keeps trying to steal my remaining fiber optics for a lamp in his room.

Future improvements include better internal support, googly eyes to cover the logos, and a fifth plume to fill out the front. See you next year!

OFBC 2.0

For Toxic BBQ 13 (DEFCON 25), we returned to the OFBC to see if we could improve the design and add some needed table decorations.

The first step was to simplify the PCB creation. I created a new layout in Fritzing that reduced whitespace. It also moved off-board components like batteries and the LED modules to use JST connectors for easy installation and swapping.  OSH Park did a great job with the PCBs. I was able to directly convert the Fritzing designs to printable format. Each board was less than 2 bucks by the time we finished. Never again will I make my own PCBs by hand. 

Sparkfun supplied most of the same components for about 15 bucks per light. Here is an updated BoM for this case:

• Battery: 850mAh Lipo
• Switches: Hinge Lever Micro Limit Switch
• Mosfet: N-Channel 60V 30A
• Transistor: NPN Transistor
• Resistors: 100K and 3.5 Ohm Resistors
• Slide Switches (ensure pitch matches the PCB)
• LED: Cool White, Aluminum Backing

Next, we redesigned the case. Instead of a three piece design requiring glue to assemble, the two pieces would be a base and a lid with a logo. Everything could be screwed into designed posts and covered with the lid. It was a snap. Production was easier with Shapeways. However, this lead to had longer lead times that prevented us from delivering to the barbecue. The prototyping went well and matched the designs, but the mass printings were so delayed that they didn't arrive in time for the barbecue even with expedited shipping. The resin product looked much better than the filament-printed 1.0 model. The cost at 20 bucks or so each was not prohibitive, but it certainly wasn't mass-market ready.

PCB at OSH Park
Case Files on GitHub

Design Pics

Updated Lid Design for Toxic BBQ 2018