Published: December 11, 2018, Edited by: Daniel Davidsen

Shrink your Arduino Projects

If you don't use a lot of pins from the Arduino you can use a atiny85 instead. It has a pin layout as the following picture.

For programming a attiny85 you need to program it though a Arduino UNO ( the standard one ), FABLAB has a programming shield for easy programming else can build all needed connections in a breadboard (read how here. )

Here is a how to program the blink example:

Insert the ATtiny85 The chip has a small ring one corner. This means it's this the chip pin 1 (not to be misunderstood with programmable pin 1!).
The pin 1 should be in the upper left corner.

Install the ATtiny library.

  • Open the Arduino IDE program
  • Click "Tools"
  • Click "Boards"
  • Click "Boards Managers"
  • Search "attiny"
  • Click "install"

Find the blink code

  • Click "File"
  • Click "Exsamples"
  • Click "01.Basic"
  • Click "Blink"

Slide change to code

The ATtiny85 doesn't have a build in LED therefor, find and replace all 3 location with "LED_BUILDIN" change to "0" or what pin you would like to use.

Insert a LED in PIN 0 and GND (remember 220 ohm resistor)

Upload code

  • Click "Tools"
  • Click "Board"
  • Click "Attiny25/45/85"

  • Click "Tools"
  • Clcik "Processor XXX"
  • Click "ATtiny85"

  • Click "Programmer XXX"

  • Click "Arduino as ISP"


The LED should now blink every second.