DEF CON 23 Badge Mod: Digital Analog Clock

I thought the idea of a playable vinyl record badge was awesome, but I wanted to make my badge flashier by adding some extra functionality to it. I had brought a box of extra parts with me, and I decided it’d be cool to add some LEDs around the outside (what’s flashier than flashing LEDs?). As I started to do this, I realized what I was making resembled an analog clock, and it just so happened that I had 12 LEDs with me (one for each hour/5 minute marker).

front of the badge

Earlier that morning, while out on a run down the strip, I stopped by a Walgreens to pick up a cheap pair of nail clippers and eye brow tweazers. I was able to use the nail clippers to clip and stip wire, and the tweazers saved my finger tips while soldering wires to the LEDs.

back of the badge

I hooked the LEDs up to an Arduino Pro Mini I had also brought with me, along with two buttons (for setting the time), and a jumper (for changing the mode; set vs display). Below is the schematic for the design. The functionality is very simple and straightforward. An LED is illuminated for the hour, and another for the minute (down to 5 minute intervals). The hour LED stays solid, while the minute LED blinks every second (to distiguish itself from the hour, but also to allow for counting seconds). Every 10 seconds LEDs turn on in a sort of ‘wave’ animation where the 12 o’clock LED turns on and off, followed by the 1 o’clock LED, and so on until returning to 12 o’clock.

schematic for add-on

To set the time, make sure the settime pin is jumpered to ground. Use the buttons to increment the hours and mintues (both roll over after hitting 12 or 60 minutes). The minutes are one at a time, so it takes 5 button presses to see the minute LED change.

Thant’s about it. It was a fun project to make at DEF CON, and it got some friendly compliments. The hardest part was organizing and soldering the rat’s nest of wires to and from the LEDs on the badge. I’m looking forward to next year being an electronic badge year!

Written on September 5, 2015