Project: Kiwicon 9 Unofficial Badge (2015) by follower

Unofficial badge for Kiwicon 9.

Features

Provides seven different lighting modes (including blinking-all-green "OK to talk with me" and blinking-all-red "Please don't talk to me" social networking assistance modes) and doubles as a Christmas tree decoration with festive red/green lighting (as the conference was in December).

The rear features an area to write hacker handle/Twitter name:

Design and implementation

Designed using KiCad PCB capture and layout software.

Uses Atmel ATtiny85 microcontroller running an Arduino sketch. Programmed with a USBtinyISP programmer with a 2x3 header inserted into the connector at the end of the cable and held against the PCB.

Circuit uses "charlie-plexing" for LED control due to limited number of pins on microcontroller.

Lessons learned

Two issues impacted the programming of the board:

  1. Use of through-hole rather than SMD footprint for the programmer connector lead to a less stable physical connection.

  2. The use of the microcontroller's ISP programming pins to also control LEDs significantly negatively impacted programming reliability until the USBtinyISP was modified (as per).