Attiny Micro

A small board for the Attiny85 and pin compatible variants for embedding into projects.

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Yet another Attiny-based project. It was inspired by wanting a low-cost board that was small enough to easily fit into projects. It's designed for the Attiny85 and pin-compatible variants. The PCB dimensions are approximately 0.72 x 0.56 inch (18.2 x 14.2 mm.)

I needed something that allowed me to embed my Attiny85 into projects in a more permanent fashion. My T85 target board is great for doing prototypes and such but is a tad on the big side.  The goals included something that was low-cost, versatile, and small.  After playing around in KiCad for a bit, I came up with the board.  The board costs under $2USD for three copies from OSHPark which accomplished my first goal.

The board is a bit of a compromise between versatility and size. Something such an ICSP header would be nice, but that would grow the size of the board a bit with a standard-size header. Simply using a socket, allows for pulling the micro and placing it in the T85 target board to flash updated firmware as needed.

For 3 of the I/O pins (P5-P7) there is an option to connect to the pin header pads via either a resistor(0805 size) or simply using a jumper. The other two I/0 pins directly connect to the pin header pads.  Pin headers can either be installed or just directly solder wires. A extra VCC and GND pad are also added to give more flexibility.

KiCad board files

x-zip-compressed - 37.45 kB - 03/12/2018 at 15:16


  • 1 × Attiny Micro board
  • 1 × 0805 .1uF ceramic capacitor
  • 1 × 0805 10K resistor for the reset pin optional but recommended
  • 1 × 0805 resistors/jumpers as needed for your particular application for the three I/O pins that have an option for a resistor
  • 1 × DIP Attiny85(or pin compatible variant)

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  • Some additional ideas

    mcu_nerd03/12/2018 at 16:14 0 comments

    I've been thinking about potential improvements/add-ons.  One of the things that the board lacks is an ICSP header. I could make an add-on board board with an ICSP header that can stack on top of it. A downside though is that it wouldn't work for configurations in which wires are directly soldered to the Attiny Micro board. 

    I could also do various mini add-on boards that stack on the Attiny Micro which could also make it function as a development platform but the lack of an ICSP header currently makes that less viable(ICSP header add-on board idea could possibly fix that).

    I could also try squeezing in 2 more 0805 size resistor pads for the 2 remaining I/O pins.

    Tell me what you think in the comments!

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Eric Hertz wrote 04/01/2018 at 03:46 point

I designed a project a while back where an ATtiny45 was used as an EDID chip... one of those board-places where I got ten copies, but only needed three... I've cut off that portion of the remaining boards several times just to use it as a tiny45 breakout... Love the '85/'45 (only chose the '45 since it was available in a *really small* surfacemount package)

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