Here’s How Hard It Is To Produce A Conference Badge

Making an event badge is hard work. Making a single prototype badge is hard enough, but the whole process of sourcing components and coordinating manufacture for hundreds of badges on a shoestring budget with the looming deadline of the event and its expectant attendees is a Herculean task.

[Uri Shaked] is one who bears the scars of producing an event badge, and he’s written a fascinating account of his experience. The conference in question was Aramcon 2019, a private tech event in Israel, and the badge has an nRF52840 driving an e-ink display, multi-colour LED, and an audio codec, with a set of full-size keyboard keys as user input. Since the nRF chip supports mesh networking, the idea was to produce a badge capable of streaming audio across the entire event.

A clothes-pin as a programming jig, we like it!
A clothes-pin as a programming jig, we like it!

We follow the team through nail-biting months of prototype boards, reversed connectors with last-minute cable bodges, compatible parts that didn’t turn out to be quite so compatible, and wrong footprints, and see them arriving at a badge which worked, but without the audio they’d hoped for. Along the way they came up with a clothes-pin-based programming jig which would surely have merited its own Hackaday write-up had they covered it on its own. Demonstrating the mesh networking by turning a whole auditorium’s worth of badges LEDs yellow was their reward, and we can see they’ve produced a very creditable badge. We particularly like the use of keyboard key switches, and we commend them for planning a life for the badge after the event.

Our Hackaday colleague [Brian Benchoff] is a veteran of badge production, read his write-ups of the genesis of our Superconference 2017 badge and the Tindie dog badge. Meanwhile the keen-eyed among you may recognise the nRF52840 as the guts of the latest generation of Particle boards.

The Science Of Reverse Mounted LEDs

One of the most artistic applications of electrical engineering in recent memory is the burgeoning badgelife movement. This is an odd collective of people who are dedicating their time to rendering their own accomplishments in printed circuit boards. Of the entire badgelife collective, one of the most visible efforts are in Shitty Add-Ons, with a particular focus on reverse-mounted LEDs. Yes, you can install SMD LEDs upside down, and if you have your copper layers right, the light will shine through the badge.

One of the most prominent users of reverse mounted LEDs is [TwinkleTwinkie], and now finally we have a writeup on the science of reverse mounted LEDs. There’s a lot to unpack here, so buckle up and prepare to burn the tips of your fingers on a soldering iron.

For truly reverse-mounted PCBs, there are two options. The first, and most expensive, are ‘reverse gullwing’ LEDs. These LEDs are just like normal LEDs, except the SMD pads are reversed, allowing you to mount it so the light shines into the PCB. These LEDs are expensive, rare (only three companies make them), and they don’t really give off a lot of light. The other solution to reverse-mounting a LED is simply taking a standard 1206 SMD LED and manually soldering it upside-down. This is not pick and place friendly, although I’m sure you could find an LED manufacture that would put LEDs in reels upside-down if you want.

Side view LEDs

The takeaway for reverse mount LEDs is pick two: good, fast, or cheap. Reverse gullwing LEDs are expensive, but can be pick and placed and provide sufficient illumination. Hand-soldered LEDs installed upside down are cheap, slow, but also good.

But there is another option. Side view LEDs are a thing, and they can be pick and placed. You can get them in every color, and even UV. [Twinkle] has experimented with side-view LEDs in place of reverse mounted LEDs, and the results are promising. By putting the side view LED next to part of a PCB without copper or soldermask, there is some light bleed through the PCB. It’s somewhat uneven, but with a hot melt glue diffusor, you can get a somewhat decent bar of light being emitted through a PCB.

If you want to put blinky on a PCB, you have a lot of options. If you want to put blinky on a PCB without having any visible light source, these are your options. This is the state of the art in artistic PCBs, and we’re so glad [Twinkle] could share it with us.

Cyphercon Badge Has a Paper Tape Reader Built In

Cyphercon 4.0 came to life in Milwaukee, Wisconsin on Thursday and the conference badge is a brilliant and engaging design. At first glance it looks like a fairly mundane rectangular badge. But a closer look reveals simplistic elegance wrapping around some clever mechanical design and the awesome interactive mechanism of being able to read paper tape.

That’s right, this badge can read the series of holes punched in the long paper strips you normally associate with old iron of 50 years ago.

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Jaromir Sukuba: The Supercon 2018 Badge Firmware

If you missed it, the Hackaday Supercon 2018 badge was a complete retro-minicomputer with a screen, keyboard, memory, speaker, and expansion ports that would make a TRS-80 blush. Only instead of taking up half of your desk, everyone at the conference had one around their neck, when they weren’t soldering to it, that is.

The killer feature of the badge was its accessibility and hackability — and a large part of that was due to the onboard BASIC interpreter. And that’s where Jaromir comes in. Once Voja Antonic had finalized the design of the badge hardware for our conference in Belgrade in the spring of 2018, as Jaromir puts it, “all we needed was a little bit of programming”. That would of course take three months. The badge was battle-tested in Belgrade, and various feature requests, speed ups, and bugfixes were implemented (during the con!) by Jaromir and others.

Firmware work proceeded over the summer. Ziggurat29 helped out greatly by finding ways to speed up the badge’s BASIC interpreter (that story is told on his UBASIC and the Need for Speed project page) and rolled into the code base by Jaromir. More bugs were fixed, keywords were added, and the three-month project grew to more like nine. The result: the badge was in great shape for the Supercon in the fall.

Jaromir’s talk about the badge is supremely short, so if you’re interested in hacking a retrocomputer into a PIC, or if you’ve got a badge and you still want to dig deeper into it, you should really give it a look. We don’t think that anyone fully exploited the CP/M machine emulator that lies inside — there’s tons of software written for that machine that is just begging to be run after all these years — but we’re pretty sure nearly everyone got at least into the basement in Zork. Dive in!

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Badge.Team: Badges Get A Platform

Electronic conference badges are now an accepted part of the lifeblood of our community, with even the simplest of events now sporting a fully functional computer as an eye-catching PCB on a lanyard. Event schedules and applications are shipped on them, and the more sophisticated ones have app libraries and support development communities of their own.

The trouble is that so often those badges fail to live up to their promise, and one reason behind that stems from the enormity of the task facing a badge team when it comes to firmware for a modern badge. There is some fascinating news from the Netherlands  that might reduce some of those firmware woes though, badge.team is a freshly-launched project that provides a ready-made badge firmware with the promise of both stability and long-term support. If you’re making a badge, or even a one-off device using the ESP32, this is a project worth checking out.

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Voja Antonic: Designing the Cube

Voja Antonic designed this fantastic retrocomputing badge for Hackaday Belgrade in 2018, and it was so much fun that we wanted to bring it stateside to the Supercon essentially unaltered. And that meant that Voja had some free time to devote to a new hardware giveaway: the Cube. So while his talk at Supercon in November was ostensibly about the badge, he just couldn’t help but tell us about his newer love, and some of the extremely clever features hidden within.

It’s funny how the hardware we design can sometimes reflect so much on the creator. Voja designed then-Yugoslavia’s first widely used home computer (and published the DIY plans in a magazine!). Thousands were built from their kits. The Galaksija was a Z80-based design with a custom BASIC that was just barely squeezed into the available 4K of ROM. So you shouldn’t be shocked that the retro-badge has a working keyboard and a nice BASIC on board.

But let’s jump ahead to the Cube, because that’s even more of a passion project. On the outside, they’re very simple devices, with only a USB port and a sweet diffused LED ring visible. Aesthetic? Minimalistic? Beautiful, honestly.
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Program This Badge in Lisp

This hardware badge is a computer programmed with Lisp. You can write your own programs right on the badge using the built-in keyboard, as long as you know Lisp.

If there’s one thing we really like to see, it’s people advancing their own projects based on inspiration from others. The Lisp Badge by [David Johnson-Davies] is a perfect example. With an interface inspired by [Voja Antonic’s] hardware design for the 2018 Hackaday Belgrade Conference Badge, this version is an upgrade of an earlier single-board Lisp machine, now sporting an integrated keyboard.

Unlike the Belgrade badge, which is programmed in BASIC, this new badge is programmed in uLisp, a subset of common lisp designed for microcontrollers. Let’s face it, BASIC is retro, but Lisp is even more so, only pre-dated by FORTRAN as the oldest high-level language. So, if you’re into retro-style programming on small devices (physically small, that is), you should consider building one of these.

A 16 MHz ATmega 1284P serves as the badge’s brain, allowing storage for 2,816 Lisp cells, while the 256×64 pixel OLED display shows 8 lines of 42 characters in 16 gray levels. A full complement of I/O connections includes four analog inputs, two analog outputs, I2C, SPI, serial, and a handful of GPIOs for interfacing with just about anything. Power comes from a LiPO battery, which at a nominal voltage of 3.7 V doesn’t quite meet the datasheet requirements for running the processor at 16 MHz, although it seems to work fine in practice. Really cautious builders could opt for a 12 MHz crystal transplant to avoid any possibility of problems.

The keyboard layout is optimized for uLisp programming: unnecessary keys have been removed and the all-important parenthesis are afforded their own dedicated keys on the bottom row. This is presumably for convenience of use, but we suspect this will also make it easier to replace the parenthesis key switches when they inevitably wear out from overuse [obligatory Lisp/parenthesis joke].

As far as entering uLisp programs, you can simply use the keyboard. The built-in editor buffers a full screen of text, and includes parenthesis matching that highlights each pair as you type. We’re guessing that we won’t see Emacs implemented in the near future, so this bracket management is a great feature for a badge-based editor. If you find the keyboard difficult to type on, you can also enter programs over the serial port.

The other thing we really like to see is open-source projects. [David] doesn’t let us down on this point, either. The Eagle design files for the PCB as well as the source code for the badge are available on GitHub. The PCB is also shared on OSH Park, and there are detailed instructions for installing the bootloader and uploading the code.

If programmable badges is your thing, also check out the 2018 Hackaday Supercon Badge, the successor the Belgrade design.

Thanks to [Sven] for the tip!