I was brainstorming a badge that focused heavily on the CTFs with an incredibly easy USB connection and the CTF unlocking the badge features when correct flags are punched into it. And even before I could prototype, I wanted to make such a badge for DEF CON - in particular their immensely fascinating villages.
So I got in touch with Red Team Village and within no time they gave a big thumbs up for the idea. We started designing from scratch barely 2 months before the conference.The Design
For the first design, it was an absolute no-brainer to use the iconic Red Team Village logo. But more so, I immediately could come up with the design elements that would use the CTF blinky features - eyes and the devilish horns.
We reverse mounted the SMD LEDs to glow the eyes and horns through the PCB.
I wanted to make the badge most accessible to play the CTF so that's how we also arrived at the micro-USB port for quick, easy connection.
The badge in default mode keeps winking the LED eyes randomly. To play the CTF, don't forget to remove the coin cell from the battery holder and plug in your good old micro-USB cable.
To interface with the badge, you can use the terminal or something as easy as Arduino IDE's serial monitor. Since we were done with the production way ahead of time, we got a chance to do extensive CTF testing. The badges will work seamlessly across all platforms including newer M1 Macs.
Select your port and boot up the serial monitor. To initialise the CTF, send three stars *** in the serial monitor. This will put the badge into the CTF mode and it'll print out the artwork on the screen along with your first challenge.
Entering the first flag wrong will make the badge unresponsive. At this point, unplug the badge and plug it in again.
All the subsequent flags are to be entered in the same way. With correct flags, the badge will start unlocking the LEDs (and your bragging rights for solving the CTF).
Once you reach the final stage, the badge will remember your flags even if you disconnect the cable. Put your coin cell back in and consider yourself part of the bragworthy club.