This year we challenged the Hackaday community to develop Shitty Simple Supercon Add-Ons (SAO) that did more than just blink a few LEDs. The SAO standard includes I2C data and a pair of GPIO pins, but historically, they’ve very rarely been used. We knew the talented folks in this community would be able to raise the bar, but as they have a tendency to do, they’ve exceeded all of our expectations.

As we announced live during the closing ceremony at the 2024 Hackaday Supercon, the following four SAOs will be put into production and distributed to all the attendees at Hackaday Europe in Spring of 2025.

Best Overall: SAO Multimeter

For the “Best Overall” category, we only intended to compare it with the other entries in the contest. But in the end, we think there’s a strong case to be made that [Thomas Flummer] has created the greatest SAO of all time. So far, anyway.

This add-on is a fully functional digital multimeter, with functions for measuring voltage, resistance, and continuity. The design is a pure work of art, with its structure combining stacked PCBs and 3D printed parts. There’s even tiny banana plugs to connect up properly scaled probes. Incredible.

In the documentation [Thomas] mentions there are additional functions he didn’t have time to include in the firmware, such as modes to analyze the I2C and GPIO signals being received. Now that it’s been selected for production, we’re hoping he’ll have the time to get the code finished up before its European debut.

Fun: Etch sAo Sketch

This SAO recreates the iconic art toy in a (hopefully) non-trademarked way, with a 1.5″ inch 128 x 128 grayscale OLED display and a pair of trimpots capped with 3D printed knobs. Drawing is fun enough, but the nostalgia really kicks in when you give it a good shake — the onboard LIS3DH 3-axis accelerometer picks up the motion and wipes the display just like the real thing.

Created by [Andy Geppert], this SAO isn’t just a pretty face. Flipping it over shows an exceptionally clever technique for connecting the display board to the main PCB. Tiny metal balls (or “alignment spheres” if you want to get fancy) mate up with the mounting holes on the OLED board and center it, and a touch of solder locks it all in place.

Fine Art: Bendy SAO

While this wacky, waving, inflatable, arm-flailing SAO might look like the sort of thing that would be outside of a used car dealership, but creator [debraansell] managed to shrink it down so the point that it’s reasonable to plug into your badge. More or less.

There are several fascinating tricks at work here, from lighting the PCB from the back using side-firing LEDs to the integrated slip rings. If this one didn’t look so good, it would have been a strong contender for the “Least Manufacturable” Honorable Mention.

Functional: Vectrex SAO

Creating a replica of the Vectrex at SAO scale would have been an impressive enough accomplishment, but [Brett Walach] took this one all the way and made it playable.

The display is a 7 x 10 Charlieplexed LED matrix, while the “joystick” is implemented with a 1-button capacitive touch sensor. A PIC16F886 microcontroller runs the simplified version of Scramble, and there’s even a speaker for era-appropriate audio.

But that’s not all! This SAO was also designed to be hacked — so not only is all the hardware and software open source, but there’re various jumpers to fiddle with various settings and an I2C control protocol that lets you command the action from the badge.

Honorable Mentions

As usual, this contest had several Honorable Mentions categories — while we would have loved to put all of these SAOs into production, there’s only so much we can do before now and Spring.

[Jeremy Geppert]’s SAO LoRa Walkie Talkie was a judge favorite, for its simple good looks and the extra functionality that it brings to the table. [Scorch Works]’s SAO Infinity Mirror was absolutely beautiful to see in person, and makes a fantastic display when many of them get together. And [MakeItHackin]’s Skull of Fate SAO not only looked super when its eyes scan the room, but it could read your future as well!

Best Communication:

Using I2C to get SAOs to talk to the badge (or each other) was a big part of this contest, but we were also on the lookout for entries which helped facilitate badge-to-badge communications.

The Badge Tag NFC SAO from [Thomas Flummer] is a perfect example of both — it uses the NXP NTAG I2C Plus to provide 2K of read-write storage that can be accessed either internally through the I2C bus by the badge, or externally by an NFC device such as a smartphone. Modeled after a traditional conference name tag, this SAO was designed to make it easier for sharing your contact info with others during a busy con.

Infrared Communication SAO by [Alec Probst] brings infrared communications to the party, while looking like a classic TV remote. Though the original idea was to get this working in conjunction with the badge to act as a sort of TV-B-Gone, it ended up being used as part of a laser tag game during Supercon.

The GAT Nametag SC8 from [true] tackles communication on a more human level by providing a digital name tag for your badge. This compact board’s secret trick is the ability to make sure your name is legible no matter what its orientation thanks to a LIS2DW12 accelerometer that can detect the SAO’s orientation relative to the ground. RGB LEDs catch the viewer’s eye, but it’s the incredible firmware with seemingly endless options for text styling and tweaks that really set this build apart.

Light Show:

There’s little question that Featuring You! from [Nanik Adnani] is a perfect entry for this category. Nominally, it’s a little arrow you can write your name on and use a name tag. But power it up and you can dazzle anyone standing too close with its array of marching white LEDs. In a particularly nice touch, the circuit is implemented with only discreet components — no microcontroller.

The reDOT_RGB from [Alex] is a tiny 5×7 RGB LED matrix with a minuscule ATtiny816 MCU around the back to control the show. At just 8 x 11 mm, it’s hard to overstate just how tiny this SAO is.

While on the subject of tiny boards, the
Persistence of Vision POV Display is another entry not much larger than the SAO connector itself. Using a row of five tiny white LEDs and a ADXL345 accelerometer, [Michael Yim] is able to write text in mid-air thanks to the gullibility of the human eye.

Least Manufacturable:

Simple Add-Ons are essentially an art form, so it’s not surprising to find that they don’t often lend themselves to mass production. Several of the entries this yeah would be a real challenge to make in large numbers, but the one that really keeps us up at night is the ultra tiny smart SAO from [Alex].

This board is designed to fit inside the space between four header pins. Thanks, but no thanks.

Raising the Bar

Our hope this year was to elevate the Simple Add-On from a decorative piece of flair to something functional, and potentially, even useful. The results were incredible, and while we can only pick four winners this time around, every entry helped push the state-of-the-art forward in its own way. It’s hard to imagine how the SAO envelope can be pushed any further, but we can’t wait to find out.

There are a lot of fantastic things about Hackaday Supercon, but for me personally, the highlight is always seeing the dizzying array of electronic bits and bobs that folks bring with them. If you’ve never had the chance to join us in Pasadena, it’s a bit like a hardware show-and-tell, where half the people you meet are eager to pull some homemade gadget out of their bag for an impromptu demonstration. But what’s really cool is that they’ve often made enough of said device that they can hand them out to anyone who’s interested. Put simply, it’s very easy to leave Supercon with a whole lot more stuff than when you came in with.

Most people would look at this as a benefit of attending, which of course it is. But in a way, the experience bummed me out for the first couple of years. Sure, I got to take home a literal sack of incredible hardware created by members of our community, and I’ve cherished each piece. But I never had anything to give them in return, and that didn’t quite sit right with me.

So last year I decided to be a bit more proactive and make my own Simple Add-On (SAO) in time for Supercon 2023. With a stack of these in my bag, I’d have a personalized piece of hardware to hand out that attendees could plug right into their badge and enjoy. From previous years I also knew there was something of an underground SAO market at Supercon, and that I’d find plenty of people who would be happy to swap one for their own add-ons for mine.

To say that designing, building, and distributing my first SAO was a rewarding experience would be something of an understatement. It made such an impression on me that it ended up helping to guide our brainstorming sessions for what would become the 2024 Supercon badge and the ongoing SAO Contest. Put simply, making an SAO and swapping it with other attendees adds an exciting new element to a hacker con, and you should absolutely do it.

So while you’ve still got time to get PCBs ordered, let’s take a look at some of the unique aspects of creating your own Simple Add-On.

Low Barrier to Entry

To start with, let’s cover what’s probably the biggest benefit of making an SAO versus pretty much any other kind of electronic device: essentially all the hard work has been done for you, so you’re free to explore and get creative.

Consider the SAO standard, such as it is. You know there’s going to be 3.3 volts, you know physically how your device will interface with the host badge, and should you decide to utilize it, there’s an incredibly common and well-supported protocol (I2C) in place for communication with other devices.

There’s even a pair of GPIO pins thrown in for good measure, which more nuanced versions of the SAO spec explain can be used as the clock and data pins for addressable LEDs. In either event, they provide an even easier way to get your SAO talking to whatever it’s plugged into than I2C if that’s what you’re after.

Not having to worry about power is a huge weight off your shoulders. Voltage regulation — whether it’s boosting the output from a battery, or knocking down a higher voltage to something that won’t fry your components — can be tricky, and has been known to trip up even experienced hardware hackers. There’s admittedly some ambiguity about how much current an SAO can draw, but unless you’re looking to push the envelope, it’s unlikely anything that fits in such a small footprint could pull enough juice to actually become a problem.

Minimal Investment

Another thing to consider is the cost. While getting PCBs made today is cheaper than ever, the cost still goes up with surface area. Especially for new players, the cost of ordering larger boards can trigger some anxiety. Luckily, the traditional SAO is so small that having 20, 30, or even 50 of them made won’t hit you too hard in the wallet. Just as an example, having 30 copies of the PCB for my first SAO fabricated overseas cost me around $12 (shipping is the expensive part).

In fact, an SAO is usually small enough that a quick-turn prototype run with one of the domestic board houses might be within your budget. I’ve been playing around with a new SAO design, and both DigiKey and OSH Park quoted me around $40 to have a handful of boards produced and at my doorstep within 5 to 7 days.

Now assembly of your SAOs, should you outsource that, can still be expensive. Even though they’re small, it’s all going to come down to what kind of parts you’re using in the design. I was recently talking to Al Williams around the Hackaday Virtual Water Cooler, and he mentioned the cost to have just a handful of his SAO made was in the three figures. Then you look at the parts he used in the design, and it was clear this was never going to be a cheap build.

But even if you’ve got deep enough pockets to pay for it, I’d personally recommend against professional assembly in most cases. Which leads nicely into my next point…

A Taste of Mass Production

Being hobbyists, the reality is that most of us never get the opportunity to build more than a few copies of the same thing. For a personal project, there’s rarely the need to build more than one — and even if you count the early prototypes or failed attempts, it’s unlikely you’d hit the double digits.

But for an SAO, the more the merrier. If you’re planning on swapping with others or giving them away, you’ll obviously want quite a few of them. There’s no “right” number here, but for an event the size of Supercon, having 50 copies of your SAO on-hand would be reasonable. As mentioned earlier, I went with 30 (in part due to the per-unit cost) and in the end felt I should have bumped it up a bit more.

But even at 30, it was far and away the largest run of any single thing I’d ever done. After assembling the third or fourth one, I started to pick up on tricks that would speed up the subsequent builds. Where applicable, hand-soldering quickly gave way to reflowing. After some initial struggling, I realized taking the time to make a jig to hold the more fiddly bits would end up saving me time in the long run. Once ten or so were in various states of completion, it became clear I needed some way to safely hold them while in production, so I ended up cutting a couple board holders out of wood on the laser cutter.

Looking back, this part of the process was perhaps what I enjoyed the most. As you might expect, I’ve been involved with  badge production at significant scales in the past. If you have a Supercon badge from the last several years, there’s an excellent chance I personally handled it in some way before you received it. But this was an opportunity to do everything myself, to solve problems and learn some valuable lessons.

Finding a New Community

Finally, the most unique part of making your own SAO is that it’s a ticket to a whole new subculture of hardware hacking.

There are some incredibly talented people making badges and add-ons for the various hacker cons throughout the year, and there’s nothing they like better than swapping their wares and comparing notes. These folks are often pushing the very limits on what the individual hacker and maker is capable of, and can be a wealth of valuable information on every aspect of custom hardware design and production.

When you put your creation up on the SAO Wall at Supercon, or exchange SAOs with somebody, you’re officially part of the club, and entitled to all the honors and benefits occurring thereto. Don’t be surprised if you soon find yourself on a private channel in an invite-only chat server, pitching ideas for what your next project might be.

With a little over a month to go before the 2024 Hackaday Supercon kicks off in Pasadena, and a couple weeks before the deadline on submissions for the Supercon Add-On Contest, there’s still time to throw your six-pin hat into the ring. We can’t wait to see what you come up with.

Nixie tubes are cool, and hackers like them. Perhaps for those reasons more than any other, [Kevin Santo Cappuccio] has developed a very particular Simple Add-On for the 2024 Hackaday Supercon badge.

The build began with a Burroughs 122P224 Nixie tube, and a HV8200 power supply. The latter component is key—it’s capable of turning voltages as low as 3 V into the 180V needed to power a Nixie. Then, an 18-position selector switch was pulled out of a resistance substitution box, and [Kevin] whipped up a basic DIY slip ring using some raw copper clad board.

Smoosh it all together, and what do you get? It’s a Nixie tube you can spin to change the number it displays. Useful? Hardly, unless you want to display varying glowing numbers to people at unreadable angles. Neat? Very. Just don’t touch any of the pins carrying 180 V, that’ll sting. Still, [Kevin] told us it’s pretty tucked away. “I’m totally comfortable touching it, but also would get sued into oblivion selling these on Amazon,” he says.

As [Kevin] notes in his post, the 2024 badge is all about the add-ons— and there’s actually a contest! We suspect [Kevin] will have a strong chance of taking out the Least Manufacturable title.

If you need more information about the Simple Add-On (SAO) interface, [Brian Benchoff] posted the V1.69bis standard on these very pages back in 2019. Apparently the S used to stand for something else. Video after the break.

One of our favorite parts of Hackaday Supercon is seeing all the incredible badge add-ons folks put together. These expansions are made all the more impressive by the fact that they had to design their hardware without any physical access to the badge, and with only a few weeks’ notice. Even under ideal conditions, that’s not a lot of time to get PCBs made, 3D print parts, or write code. If only there was some standard for badge expansions that could speed this process up…

But there is! The Simple Add-On (SAO) standard has been supported by the Supercon badges since 2019, and the 2×3 pin connector has also popped up on badges from various other hacker events such as HOPE and DEF CON. There’s only one problem — to date, the majority of SAOs have been simply decorative, consisting of little more than LEDs connected to the power pins.

This year, we’re looking to redefine what an SAO can be with the Supercon Add-On Contest. Don’t worry, we’re not changing anything about the existing standard — the pinout and connector remains the same. We simply want to challenge hackers and makers to think bigger and bolder.

Thanks to the I2C interface in the SAO header, add-ons can not only communicate with the badge, but with each other as well. We want you to put that capability to use by creating functional SAOs: sensors, displays, buttons, switches, rotary encoders, radios, we want to see it all! Just make sure you submit your six-pin masterpiece to us by the October 15th deadline.

Best of the Best

What’s in it for the winners? Why, nothing short of Hackaday immortality: we’ll put the top SAOs into production and distribute them to each attendee at Hackaday Europe in 2025. Because we actually have to get these things made, entries will have to meet all of the manufacturing requirements outlined on the Hackaday.io page Contest page to qualify.

In addition to a single Best Overall winner, we’ll be picking a top entry for each of the following categories:

• Functional: This challenge is about pushing the envelope for SAOs, so for this category we’ll be looking for the most capable add-on.
• Fine Art: We’ve seen some absolutely gorgeous SAOs over the years, so even though we’re largely pushing for function over form this year, we still want to acknowledge the incredible artistry that goes into them.
• Fun: It’s not all about business. SAOs are often a bit tongue in cheek, with many referencing online memes or parts of hacker culture. If you want to win in this category, you’ll need to lighten up a bit.

Honorable Mention

We know this community too well to believe you’ll all stick to the predefined categories, so as usual in our contests, we’ll be keeping an eye out for entries that best exemplify the following Honorable Mention categories.

• Coolest Toys: We’re suckers for interesting parts, so the SAO selected for this category will be the one with the most unique or impressive electronic components onboard.
• Light Show: We want to challenge the idea that SAOs are just for blinking LEDs, so naturally, at least one of you is going to go against the grain and add as many LEDs as possible.
• Most Ambitious: Sometimes, it’s the thought that counts. Whether or not the final product worked as expected, the SAO selected for this category will be the one that took the biggest swing.
• Best Communication: Getting SAOs to talk to the badge and each other is what this contest is really all about, so we’re looking for the one example that really ran with the concept.
• Least Manufacturable: SAOs often employ design or assembly hacks (like mounting LEDs upside-down) that don’t scale well. In this category we’re looking for hand-crafted masterpieces. To quote Hunter S. Thompson, “A high-powered mutant of some kind never even considered for mass production.”

A Little Inspiration

There’s no shortage of gorgeous SAOs out there already, just search Hackaday.io or Tindie, and you’ll come up with dozens of badge add-ons that you didn’t even know you needed until right now. But as for examples of functional SAOs that do more than just blink LEDs…that’s quite a bit harder. We weren’t joking when we said they’ve been quite rare so far.

But we can point you towards a couple resources that should help you get started. Our own [Arya Voronova] wrote up her tale of creating a Jolly Wrencher SAO back in 2022 that goes over the basics, and we’d also recommend taking a look at her ongoing “I2C for Hackers” series of articles if you need to brush up on the communication side of things. If you need some pointers on the artistic front, you can’t go wrong following in the footsteps of [TwinkleTwinkie]. His Supercon 2019 talk PCB Art is Pain is a fantastic look at pushing the envelope of PCB design and production, and his Hackaday.io post about backlighting board art is required reading around these parts.

Our friends in the Whiskey Pirates crew sent me the unofficial DEF CON badge they built this year. The Internet of Batteries QUANTUM provides power and connectivity to the all-important add-on badges of DC28. The front of the badge is absolutely gorgeous to the point I don’t really want to solder on my add-on headers and disrupt that aesthetic.

The gold-plated copper makes for a uniformed and reflective contrast to the red solder mask which occupies the majority of the front. Here we see the great attention to detail that [TrueControl] includes in his badges. The white stripe of silk screen separating the two colors is covered by some black detailing tape that looks much better than the white.

The antenna of the ESP32 module poking out the underside of the gold cover end of the badge gets its own rectangle of the holographic sticker material, the same as the sheet of stickers that was included in the box. Both decals are small details that make a huge difference to your eye.

The line of nine RGB LEDs have black bezels which goes along with the black stripe motif and underscores the typography of the badge name. These lights are hosted on a daughter board soldered to the underside of the badge with a slot for the LEDs to pass through. They are addressed in a 2×15 matrix that is scanned on the low side by the PSoC5 that drives the badge. This low-res image shows that daughter board before the lithium cell is placed.

User control is provided by a number of capacitive touch pads, one under the word DEF, another under the word CELL, and finally a row of five chevron shaped pads just above those words. The role of the badge is to provide power to add-ons so it makes sense that recharging is built in via a micro USB port.

One trademark design choice worth mentioning is the treatment of four white LEDs, one next to each of the SAO (“Shitty Add-on”) footprints. At first I thought these used cutouts in the board just like the RGB strip, but that isn’t the case. Instead, copper has been kept out of this area to expose the FR4 substrate. A normal surface-mount LED is hand soldered upside down so that it shines toward the board, using this keepout area in the PCB design as a diffuser. This is a trick that [TrueControl] used on last year’s Space Force badge, and while I personally found it quite tricky to get the hang of soldering them, it’s more cost effective than sourcing proper undermount LEDs.

As with many badgelife offerings, this is still a work in progress. The firmware that shipped with the badge is still in the “Hello World” phase. Development is ongoing, but many bold feature claims are made on the project’s GitHub page. The planned wireless features include a “Captive Arcade” which can be logged into via the WiFi access point provided by the ESP32. This makes it possible to to display analytics for power usage on each of the four SAO ports, and there’s even plans for a mesh network that incorporates socially interactive features like a chat room and private messages. On a battery?!

Speaking of those SAO ports, there are both male and female headers provided. The idea is that the DEF CELL can be used to power not only an add-on, but a badge as well. When equipped with the female shrouded pin header it effectively becomes an add-on for another badge, with the important distinction that this add-on has a Lithium battery and will “back-power” the host badge via the SAO port. Is that in the spec? No, that’s why this standard is known as “shitty”, there is inherent risk to connecting devices by different makers using these ports. But it might work without problems, it really depends on the host badge.

With both Bluetooth and WiFi available through the ESP32, and an I2C pin as part of each SAO footprint, it should be possible to use DEF CELL to show meaningful changes on add-on boards based on triggers from the Internet, or devices within wireless range of the badge. That’s a hack for the future, and certainly something we hope to see around your neck at next year’s DEF CON.

It’s April, which means all the people responsible for doubling the number of badges at DEF CON are hard at work getting their prototypes ready and trying to fund the entire thing. The first one out of the gate is Da Bomb, by [netik] and his crew. This is the same team that brought you the Ides of DEF CON badge, a blinky wearable multiplayer game that’s SPQR AF. Da Bomb is now a Kickstarter campaign to get the funding for the run of 500, and you’re getting a wearable badge filled with puzzles, Easter eggs, and a radio-based sea battle game that obviously can’t be called Battleship, because the navy doesn’t have battleships anymore.

Speaking of badges and various badge paraphernalia, there’s a new standard for add-ons this year. The Shitty Add-On V.1.69bis standard adds two pins and a very secure shrouded connector that solves all the problems of last year’s standard. [AND!XOR] just released a Shitty Brooch that powers all Shitty Add-Ons with a CR2032 battery. All the files are up on the Gits, so have fun.

You can 3D print anything if you don’t mind dealing with supports. But how to remove supports? For that [CCecil] has a great tip: use Chap stick. This is a print that used supports and it’s perfectly clean, right off the bed. By inserting a suspend (M600) command at the z-height of the top of the interface layer, then adding Chap stick on the top layer, everything comes off clean. Neat.

Speaking of 3D printing, here’s a project for anyone with the patience to do some serious modeling. It’s a pocket Soviet record player, although I think it’s more properly called a gramophone. It’s crank powered, so there’s a spring in there somewhere, and it’s entirely acoustic with zero electronics. Yes, you’re going to need a needle, but I’d be very interested in seeing somebody remake this using modern tools and construction materials.

The last few years have seen a rise of artistic PCBs. Whether these are one-off projects with a little graphic on the silkscreen or the art of manufacturing and supply chains, these fancy PCBs are here to stay. Nowhere is this more apparent than the loose confederation of Badgelife enthusiasts, a hardware collective dedicated to making expressive and impressive electronic baubles for various hacker conferences. Here, hundreds of different hardware badges are created every year. It’s electronic art, supported by a community.

Some of these badges aren’t technically badges, but rather small, blinky add-ons meant to connect to a main badge, and these add-ons are all backed by a community-derived standard. The Shitty Add-On Standard is how you put smaller PCBs onto bigger PCBs. It is supported by tens of thousands of badges, and all of the people who are spending their free time designing electronic conference badges are using this standard.

It’s been more than a year since the Shitty Add-On standard was created, and in that time the people behind the work have seen the shortcomings of the first edition of the standard. Mechanically, it’s not really that strong, and it would be neat if there were a few more pins to drive RGB LEDs. This has led to the creation of the latest revision of the Shitty Add-On Standard, V.1.69bis. Now, for the first time, this standard is ready for the world to see.

An Oral History Of The Shitty Add-On Standard

Before the Shitty Add-On standard, there were several independent conference badges with their own hats and add-ons. The 2016 Queercon badge came with hats, powered by two small expansion ports on the top of this cuttlefish badge. The expansion ports provided power, ground, and an I2C bus on a 1×4 connector, giving these cuttlebadges unicorn horns, an emo haircut, or a top hat studded with LEDs.

In 2017, there was an obvious need for a standard for badge-addons, with even more standards created. Luke Jenkins published the MiniBadge standard for SaintCon, an impressive standard that implemented 5V, 3V3, I2C and SPI in less than a square inch. The results were impressive, with more than a dozen minibadges being built for the main SaintCon badge.

Finally, we come to the 2017 / DEF CON 25 AND!XOR badge which featured Hunter S. Rodriguez and a Futurama Brain Slug.The schematic for this Brain Slug is very simple, just an ATtiny85 microcontroller and a handful of WS2812b LEDs. It’s blinky, it’s bling, and since every board house can do green solder mask, you can make a Brain Slug PCB pretty easily. Only about ten or so of these Brain Slugs were ever made (although the Gerbers are right here so knock yourself out), but it was a precedent for add-on bling.

DEF CON 25 came and went, and a few lucky people walked away with Brain Slugs. Some time around February, 2018 — the time of Chinese New Year, because that’s obviously the best time to start any sort of electronic project — a few members of the Badgelife collective started asking a few questions. The previous two years of badgemaking showed everyone add-on badges were a thing. The future would have minibadges, or other weird PCBs hanging off the big badges. What if there were a standard for Badgelife add-ons? What if these pieces of indie electronic art could host Brain Slug-like add-ons from multiple creators? The AND!XOR badge really only supplied power to the Brain Slug, but adding holes for pin headers on a badge is effectively free. The only thing you need for this is for the entire group to come to an agreement on a standard pin out.

After literal minutes of discussion, we had a standard. It was decided that the Shitty Add-On pinout should include 3.3V, Ground, and an I2C bus on four headers arranged on a 0.1″ grid. The badges would have female sockets (or just through-holes), while the add-ons would have male pins. This is the first, and only, official documentation of the electrical and mechanical specifications of the Shitty Add-On standard. No one followed the standard, but everything worked out in the end.

Why do I say no one followed the standard? Because I’m an idiot. After using Microsoft Paint for three minutes, I whipped up a quick board that would supply power to four Shitty Add-Ons. It’s the Shitty Add-On Totem, available on OSHPark. This board is as simple as it gets, with two AA battery holders and four 2×2 headers. The design was much more clever than it needed to be; two of the headers are rotated 45° clockwise, the other two headers are rotated 45° counterclockwise. This means more add-ons will fit on your totem.

Because the first publication of the Shitty Add-On standard was…. lacking… I whipped up a quick improvement. The headers (now self-documenting on the PCB with the addition of a silkscreen circle) were copy and pasted from the OSHPark render of the Totem. This, unfortunately, is the documentation everyone used. No, the headers were never meant to be rotated forty five degrees, I was just lazy and didn’t rotate what I copied and pasted from the OSHPark render. But even if the mechanical properties of the Shitty Add-On header were incorrect, at least everyone got VCC, GND, SDA, and SCL in the right place.

The foundation was set for inter-operations between badges and add-ons. The standard was finalized in February, with DEF CON a mere six months away. Dozens of PCB artisans would create their own Shitty Add-Ons. The Official DEF CON 26 badge supported the Shitty Add-On standard. The best estimates of the production of badges per DEF CON attendees say this: At DEF CON 26, there were approximately 25,000 attendees. There were approximately 50,000 badges and add-ons that supported the Shitty Add-On standard. By any measure, Shitty Add-Ons are a successful standard. Hundreds of different Shitty Add-Ons were created. Most of them had LEDs. One was a game of people eating Tide Pods on the Blockchain. Take a look:

A Newer, Betterer Standard

I would like to preface this by saying this is not the official, final release of the Shitty Add-On V.1.69bis standard. There are a few things still being worked out, especially concerning the function of the two additional pins. However, AND!XOR has already published some reference designs for an SAO using an I2C EEPROM, identical to the Tide Pod SAO of last year. Additional functionality that should be possible will be fleshed out in the future. The reason this standard is being published now is because it’s better to put things out into the world than wait until something is perfect.

By all accounts, the Shitty Add-On standard is a success, but it was not perfect. Mechanically, standard 2×2 headers aren’t very strong, and that goes doubly so if you’re using SMD male headers on the add-on. Not many people used the I2C bus, but there were a lot of people that wanted to extend their WS2812 or APA101 RGB LED strings.

A standard isn’t a standard unless there’s a better one, so now the community of badge makers has settled on a newer, betterer standard for Shitty Add-Ons. It’s Shitty Add-On V.1.69bis (SAO.69), and it vastly increases the capability of the Shitty Add-On standard while retaining backwards compatibility.

• A New Connector!

Because of the need for a low-cost connector, and the need to retain backwards compatibility, SAO.69 will use a standard 0.1″ 2×3 connector.

Badges use 2×3 female (non pinned) headers, 0.1” pitch. Similar to last year, but 6 pins. It is highly suggested that badges use through-hole connectors, lest SAOs rip off your pads. These may be keyed, but through-hole 2×3 keyed connectors are either impossible to find or absurdly expensive. The thing to search for to find a keyed badge connector is, ‘2×3 Pin 6 Pin With Polarizing Key’. eBay will turn up results for that, but you can only buy 100 at a time. AliExpress reportedly has them, but they’re $0.40 USD / piece.

Needless to say, the keyed badge connector is rare, expensive, and difficult to find. However, it perfectly solves the problem of Add-Ons coming loose. These connectors have been verified as fitting a standard IDC shrouded header. Use the best badge connector at your own risk.

Add-ons use a 2×3 male, pinned, shrouded connectors. These are actually some of the cheapest and most ubiquitous connectors available, and if you have a device that has an AVR ISP header, this is the same connector. As with the badges, it is highly suggested you use a through-hole header for mechanical strength.

A New Pinout!

The pinout for SAO.69 is exactly the same as last year’s version, with the addition of two ‘GPIO’ pins off to the right. These will be used for various add-on types, support for addressable RGB LEDs, and serial connections.

Of course, we expect most badges to only use power, and even here we have specifications: Maximum power draw by a Shitty Add-On is 1.1 millihorsepower. If a Shitty Add-on drives a GPIO pin, it MUST be through a resistor of at least 330 ohms. No signals may exceed 3.6V. For power-only add-ons, Utilize only VCC (3v3) and GND to do whatever you want. Other pins should be NC. Don’t exceed 1.1 millihorsepower draw on your SAO.

With the addition of two new pins, we have some options for serially-addressable LEDs. For WS2812 (or NeoPixel) LEDs, badges can support WS2812-based SAOs by outputting a WS2812 datastream from the badge to an SAO to sync or drive an RGB pattern. Badges can either connect the end of their existing WS2812 strand’s data line to GPIO1, or connect a badge GPIO to GPIO1 to send a datastream meant purely for the SAO strand. Note that if you’re extending the badge’s strand of WS2812s, remember to add ~10 more to your ‘strand length’.

For APA102 (or DotStar) LEDs, drive them similar to how WS2812 works, except with two pins. GPIO1 is used for data (DO / MISO), and GPIO2 is the clock (CO / CLK). Badges may also directly connect the output of the last LED in a APA102 chain to this pin provided that the pin never exceeds 3.3V. If the APA102s are driven by a higher voltage (e.g., 5 volts), a voltage divider may be used on the badge-side to bring the output down to 3.3V. SK9822 LEDs are basically the same as APA102.

Serial/UART data is also kinda supported, but using serial on an SAO is generally a bad idea. The main reason for this is that some badges will have multiple SAO ports, all using a single bus for all pins. This means when utilizing serial, someone would have to standardize a common “badgebus” language on top of serial to differentiate a target between multiple SAOs on the same serial bus, lest there be crosstalk, etc. This is similar to what is required for nodes in pub/sub use cases like MQTT. Notes on the implementation of serial include:

• An SAO should not send output to the SAO TX pin (GPIO2) until it has received input from the badge first.
• GPIO1 will be data from the badge to the SAO (badge TX, SAO RX)
• GPIO2 will be data from the SAO to the badge (badge RX, SAO TX).
• A default baud rate of 115200 is recommended.
• Remember that use of serial at all will require working with a badge maker as it requires both hardware and software support on the badge side.

And It’s Backwards Compatible!

Although we hope the new mechanical spec will give us more resilient add-ons, there are already thousands of these add-ons deployed. SAO.69 is backwards compatible with existing add-ons! Badges still get female headers, and add-ons still get male pins. SAO.69 standard just adds two pins to the right.

There has been some talk about adding a shitty mechanical standard, such as a 3mm hole for zip ties, or somewhere an M3 bolt could be added. While this would be fantastic for loose add-ons, the shitty ‘do what you want’ option works better for us.

Is this the best standard? No, not at all. That’s where the Shitty Add-On standard gets its name. There’s no way to tell if a Shitty Add-On supports WS2812, APA102, or serial connections. There’s some talk of a resistor-based voltage divider between VCC and GND, connected to GPIO1. This could, in theory, be used to query a badge to detect if it’s a WS2812, APA102, or Serial connection. We have no idea how this would work yet. Alternatively, we could add an I2C Flash chip onto each badge, with a tiny bit of data saying what the badge is. Again, Shitty Add-On Standard.

There’s a Standard for Making Standards

The Shitty Add-On spec is, after all, just something that can be easily implemented, shoved onto a board, and shipped out with whatever conference badge you’re building. The point isn’t to take ourselves seriously, it’s only about putting more bling on boards and giving everyone a platform to experiment with small add-on PCBs.

However, and this is a big however, this is a legitimate standard born of Microsoft Paint and a desire for PCB blinky bling. This leads to the possibility of making the Shitty Add-On standard an actual standard, and yes, there’s a standard for making standards.

This is only a half-serious discussion now, but the process of making a standard begins with asking a Standards Development Organization for the approval to create a new standard based around a community’s needs. Once that’s done, it’s a matter of assembling a Working Group, iterating over a draft of the standard, and finally getting it approved by the Standards Development Organization. I think the community of badgemakers can handle putting together a few drafts of an official Shitty Add-On standard, because some of us are still running Windows and have Microsoft Paint installed. The trick is getting either the IEEE or ISO in on the game. An official, published standard of badge-to-badge communication is within our grasp, we just need someone on the inside with a sense of humor.