Wednesday 11 March 2015

A tiny ATtiny

Very tiny!
 Recently I was surprised to discover that although I've made several projects using one, I'd never built a development board around the ATtiny85. With any project there are always design choices and a couple of important ones here were:
  • Is a breadboard optional or required? If optional, you get the familiar Arduino form-factor, which can either be connected to a breadboard using jumper cables or populated with pre-built shields.
  • Design a PCB or something more ad hoc? I wanted something quickly --- I wasn't going into competition with the Teensy or Trinket.
  • If not designing your own PCB, use stripboard or protoboard? While I've never been a huge fan of protoboard, because you're basically making your own strips by blobbing solder across pads, you can get quite a high component density with it.
So I opted for the path not taken, requiring a breadboard and using protoboard, and the result is pictured above. Notice that protoboard allows the FTDI connector to be attached at right-angles to the chip (try that with stripboard!) and also exposes more of the breadboard for jumper cables (the 10k resistor connecting reset and Vcc is underneath the chip).

With the ever-useful Tiny-Safe-Boot bootloader and a bespoke entry in my arduino-tiny's boards.txt file, it's as easy as regular Arduino, at a fraction the cost!