SoOnCon Badge Hacking Workshop

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What: Workshop – All Day When: 9:30am Where: Hacker’s Haven Materials Cost: None

An all-day badge hacking workshop will be taking place in the Common Area. Attendees can freely work on their badge, electronics equipment will be available to use. There will be volunteers on hand to help attendees hack and program their badges.

UPDATE: James Bastow, the primary designer of the SoOnCon badge has even more info on his personal wiki. Information on that site may be newer than this one.


  • ATmega32U4 (Arduino Leonardo compatible)
  • Includes header pins for standard Arduino shields
  • 8x individually-controlled Superbright RGB LEDs (WorldSemi¬†WS2812)!
  • Reset & two extra buttons

Schematic & PCB

Here is the Final Schematic as well as the PCB Layout for the Badge!

Badge Code

Most badges picked up at the BBQ are not programmed with the latest code, which includes functions for the optional sound circuit. The latest code is available on our github repo here: (Download as a ZIP)

Sound Circuit Parts List

This is the parts list for the optional sound circuit. Symbols correspond with those screen printed on the SoOnCon badge:

QTY        Symbol        Part Description
1	MIC1	CMA-4544PF-W
1	R2	43K or 47K RESISTOR
2	C1, C2	10 uF polarized capacitor
2	Q1, Q2	2N7000 FET


Hardware Issues

Button issues: There were a number of reported issues relating to the three buttons either not working, staying on or working intermittently. This is caused by some overzealous soldering of the buttons, where excess solder would bridge the button pads and the ground plane surrounding them. If you have these issues, remove excess solder from the button pads and make sure they’re not bridging with anything. You will need to remove or bend the AA battery pack to get access to the button solder joints.

ICSP Header: Pins 1 and 3 of the ICSP header were reversed on the PCB. If you are trying to load code via ICSP, you will need to build an adapter that reverses these pins.

Battery Charging Warning: azend on Twitter has noted that if you hook up a 5v power supply, any dead AA batteries that are attached will start to charge. That said, the badge itself operates at 3v.

Close Comments

3 Thoughts on “SoOnCon Badge Hacking Workshop

    • Here’s Bernie’s reply:

      Originally there were several reasons for leaving R2 undecided (exact value of Vcc was unknown, no sample of the mic was available, and 10K was a poor choice for R1 apparently).

      I think most people found the circuit works if R2 is 43K. The output from Q2 – the bottom end of R5 on your board – needs to be around 2.5 to 3V dc. If you measure less than 2V, change R2 to 47K.

      What’s happening in those cases – Q2 conducts too much average current, R5 drops too much voltage. To have Q2 conduct less you want Q1 conducting more, therefore make Q1 gate more positive by increasing the value of R2.

      Other solutions are possible, such as reducing the value of R1. John Wynen suggested if R1 is 2K, R2 might be omitted. I haven’t tried this yet. I found a lot of variation in transistors’ gain, and since the 2 stages are dc-coupled, R1 might have to be different on every board.

  1. Like you said the badge runs at 3v volts. Does this mean when plugging it in via USB it’s not going to operate optimally (or at all)? I’ve not been able to get my badge to be recognized on my computer when plugged in via USB in Linux or Win 8.1. However this problem could be related to my battery pack being loose (from the button repairs), the reset button being broken (because those repairs didn’t hold), or the drivers being broken (I don’t have another Arduino to test with at the moment).