About The Badge
For this year's badge we chose an old school design. A couple years later the component shortage is still real y'all.
Manufacturing
The badge was designed and prototyped by Kevin Neubauer (@bl4cksmith@infosec.exchange) and Tyler Rosonke (@zonksec). Assembly was done by Cyber City Circuits in Augusta, GA.
Interesting Bits
1.5V design (sadly this means most LEDs won't work)
Based on the TA7642 AM Radio IC
Hackable design (see the Activities page)
Has a small transistor amp, which makes it suitable for listening on headphones
Mono audio sent to both headphone channels
RF Gain Knob
Worth it's own special mention is the RF Gain knob on the badge. This little beauty dials up or dials down the amount of power the RF tuning circuit receives. Why, you ask? This year's badge is an amazingly cheap, quick & dirty, unshielded, and non-earth grounded AM radio with a single inductor capacitor tuner.
The TA7642 chip the badge is built around is supposed to have Automatic Gain Control (AGC). Think of AGC as adjusting the RF gain down when you are dialed into a strong station and adjusting it up when you are dialed into a weak station. There's one problem though. The TA7642 doesn't actually do this very well. It actually kind of sucks at doing it, but what can you expect for a 10 cent radio chip ordered direct from China off Aliexpress?
The RF Gain knob is a hack to overcome the crappy TA7642 AGC. By turning down the power to the RF tuner you can, in some cases, achieve better selectivity across the tuner dial. Without this hack, you simply receive 1110 KFAB across the whole tuner dial while you are in Omaha. Insert joke here about a radio station that plays Fox News trying to broadcast with enough power to take over the whole tuner dial.
Hacker Playground
We wanted to provide a place to have some hardware fun on the badge. Behold! The Hacker Playground.
Here's what those cryptic letters mean:
| VCC / 1.5V | These pins carry 1.5 volts |
| GND | These are ground pins |
| O | Audio output from the radio IC pre-amplifier |
| S | Audio output from the radio IC post-amplifier and connects to the S pins on the headphone jack (unless you cut J-S). |
| TR | 1.5V and connects to the TR pins on the headphone jack (unless you cut J-TR) |
| J-S (not pictured) | Solder jumper that severs the S pin of the headphone jack from the circuit when cut |
| J-TR (not pictured) | Solder jumper that severs the TR pins of the headphone jack from the circuit when cut |
All unlabeled pins are yours to use. The are not connected to each other unless you connect them with wire or solder.
Schematic
Yes. It's a bit hard to read on this page. Open it in a new tab or get a PDF.
Super Secret Stuff
You've read this far, probably hoping to find some clues on "what's hidden in the badge" or something similar. I'm going to let you in on a secret...
Nothing. There's absolutely nothing hidden inside the badge. There's no microcontroller. No flash storage. It's an old school analog design.
If you aren't happy with this response, I don't blame you. Badge challenges are fun. Did I mention that we've still got badge challenges? Drop by the Kernelcon CTF to find out more.