Posted in Modulation

Electronic Conference Badges

Ever since attending Defcon 24 this past August, I’ve been enthralled with the idea of electronic event badges.

I’m also pondering and trying to sort out what exactly would be needed to accomplish them on a budget that could be done for a WordCamp, and have it be both hackable after the event, but also usable during — and of course, look cool.

From my experience running a WordCamp, I know that attendee gifts should normally be about or just under $10 per attendee, whereas speaker gifts should normally be about maybe $20 or so.  One handy bit is that speaker gifts are in addition to attendee gifts that they get anyways, so it’s possible to have the speaker gift be an addition to their attendee badge — like an LED display and better battery or sensors or the like.

All this compiles to roughly the following requirements for attendees:

  • $10 per badge price limit.
  • Battery powered.
  • Blinky LEDs — either pretty or useful.
  • (optional) Reprogrammable after (or during) the event.

The programmability and interactivity aspect of the badge is particularly tricky, but there’s a variety of cheap microcontroller units (MCU) like the ESP-8266 12-F that can be had for under $1 per in quantity.  Or, if you’d like something a bit easier for your attendees to reprogram, the Wemos D1 Mini which is based on the aforementioned ESP-8266 12-F can also be had for under a dollar in quantity — while it would make your badge a bit bulkier as it would need to connect to your badge via pins, rather than just soldering SMD directly to the badge — it also provides a Micro USB port to make it easier for users to connect to, without having to supply their own UART adapter.  The added bulk is likely worth it, in this case.

As an aside, the Wemos D1 Mini is also programmable via the Arduino IDE, so that may simplify the process for your attendees to hack on their badges.

The other tremendous advantage to using an ESP8266 based board as the brain of your badge is that the ESP8266 is actually a wifi chip!  That’s right, it can reach out and connect to wifi networks, or make an ad hoc network between multiple badges so they can communicate!

This opens up a number of possibilities.  Would you like to let your attendees sign up for specific sessions throughout the day, and have their badge light up an LED indicating which room they need to go to?  Totally doable!  Would you like to have every attendee’s badge light up and start blinking at the same time?  Also doable!

The one downside with being cost-constrained is that you may wind up putting in more time than expected assembling the boards.  It is possible to have your factory that manufactures the PCBs also pick and solder all the components, but that costs a bit more as well.  If you’re doing a short run of maybe 10-20 boards for just speakers or the like, it’ll probably be easier to just make them yourself.

The other option that can be explored is to have the attendee gift be a cheap system-on-a-chip linux computer somewhat like to the $5 Raspberry Pi Zero — basically giving every attendee a computer that can operate as a WordPress Server — and then have the Speaker Gift be a badge with sensors and lights and batteries that can be powered by the attendee gift.

In my exploring of this option, it seems that the simplest option may actually be the C.H.I.P. — while there are other options such as the aforementioned Raspberry Pi Zero and Orange Pi Zero, they both would necessitate also picking up MicroSD cards which can add to the price significantly — however, there are other development boards like the C.H.I.P. that include sufficient storage space on-board to simplify supply chain management.

For $9, you get a 1GHz processor, 4GB of storage space, 512MB of RAM, and both Bluetooth 4.0 and WiFi b/g/n for connectivity.  While it doesn’t have the mini-HDMI out that the Raspberry Pi Zero has, it does have composite video out on the board’s headphone jack — and the manufacturer also sells expansion boards that can add on either HDMI or VGA displays.

As an added bonus, when you need to flash your Chip, the maker also has a tremendously simple, browser-based flasher tool. For something you’re giving to attendees — many of whom may not be comfortable with flashing development boards — the visual flow can be tremendously useful as a jumping off point for many.

Then you simply need to design a badge with  the pin headers for the C.H.I.P. to plug into, work up a firmware image with things such as the event’s wifi details preloaded, and a script running on a cronjob to operate the lights — and you’ve got yourself a badge for your speakers!

Or at least that’s the plan.  At the moment, this is all theoretical, I’ve been puttering about and planning possibilities, but haven’t had occasion to actually put all of this into practice.  If any of it catches your fancy and you’d be interested in doing digital badges for your WordCamp, drop me a line on Twitter at @daljo628 and I’d be happy to help as I can.  🙂