This document provides instructions for making a simple and inexpensive PCB badge. It describes iterating on the design based on feedback, converting to a hand-solderable design, and sourcing components locally in India to keep costs low. The final design uses an ATtiny85 microcontroller and can be programmed over USB to function as a keyboard, mouse, or other USB device. It is intended to be an open-source hardware badge similar to those distributed at tech conferences.

1. How to make a PCB badge
Tavish Naruka
@ntavish

2. About me
● Embedded systems engineer, currently working at thelattice.in
● Linux, FOSS, OSHW enthusiast
● @ntavish, http://ntavish.in

3. Why
● Wanted to have an e-badge like in CCCamp,
hackaday conference etc. [rad10, r0ket]
● Wanted a somewhat interesting looking PCB
● Aims: simple, cheap, no programmer
hardware, possibly end-user assemblable
● Heart is attiny85, can be made USB
programmable, and can emulate simple(LS)
USB devices like keyboards/mice etc.

4. Iteration 1
● Posted this on mailing list
● Lots of feedback, especially from
trouble, Philip, Anool, Mitch, Sva
● Many changes

5. Iteration 2
● Converted to hand-solderable DIP
packages instead of surface mount
● Can now be distributed as a
hand-solderable kit
● Fixed some mistakes in iteration 1
● Found mistakes while testing

6. ● Started making this in kicad, is free/open source EDA tool for making
PCBs, is great
● Looked at open source hardware like digispark, and (not open) trinket etc,
and used open source software VUSB, micronucleus bootloader
● PCB ordered from seeedstudio.com; PCBpower(Gujarat), IteadStudio,
OSHpark, dirtyPCBs etc. were other options (~Rs. 200 in 5qty.)
● Had rest of the components except the diodes and the attiny controller,
ordered from rarecomponents.com (Rs. 150/1pc)
● Larger quantities would make total cost somewhere around Rs. 300
Prototyping

7. prototyping...
Dirtypcbs
Upload design, get PCB Mgsuperlabs
Add to cart, get part

8. PCB
● Pcbpower.com, most suitable
● Can make 2.4mm PCB for USB mating
● Is local, no shipping issues
● Final cost around Rs.130 per PCB (at 100
qty.)
● Lead time around 12-14 days
Final order...
Parts
● Lajpat rai market: connectors, sockets
● Ebay.in: resistors, capacitors, buttons
● Mitch is bringing attiny85, diodes from
US, better pricing there
Problem: Not sure how many badges to make still, hillhacks.in/badge_signups not a good indicator

9. What can it do?
● Run on CR2032 battery, or USB power
● Has an LED, and a button
● Can (apparently) do NTSC video
● Can (apparently) be an FM radio transmitter
● Also (apparently) color VGA, with sound and joystick
● Is programmable via USB directly(if bootloader)
● Can be used with arduino software(some config needed)
● Can emulate USB HID devices, like keyboard or mouse, what interesting
thing can be done with those?
● Has prototyping area, solder other things on it and extend functionality

10. Links
hillhacks.in/badge
Time still for (small) design changes
(1-2 days max before final order of
PCBs)
Email to: tavishnaruka@gmail.com
Also see http://delhi-oshw.github.io/