The smallest Arduino ever OLIMEXINO-85S is just 16.9 x 12.7 mm (0.67×0.5″) !



You probably remember this blog post where we announced the OLIMEXINO-NANO with only 30×30 mm dimensions.

Then we further shrink the Arduino and made OLIMEXINO-85 based on Tiny85 to 30×22 mm.

Now we decided to see how small we can go with Tiny85 and made bare minimum design based on SMD technology:

  • ATTiny85 programmable by Arduino IDE made by Digispark
  • two LEDs one for power supply and one user programmable
  • All ports available to breadboard friendly two rows at 0.4″ distance
  • can be powered by USB micro connector or by LiPo battery

this board is so small that you should keep it away from children as they can inhale it 🙂

perfect for embedding in small spaces

17 Comments (+add yours?)

  1. Michael Horne
    Dec 21, 2013 @ 14:18:33

    Wow. That is *tiny*! 🙂


  2. Tiny Giant
    Dec 21, 2013 @ 20:31:59

    So cute! ❤

    However, something between this and Olimexino-85 would probably be best, i. e., big enough to allow for stackable modules but not as big as Olimexino-85. Half-height, 0.05"-spaced headers would probably be best, since you have now Cable-40-40 for these in the shop. Useful for development would be a converter board for 0.05"-spaced headers to wider-spaced ones. And something stronger than ATTiny85 must be put on the small boards. 🙂

    Since it is too late for Christmas, you should build some for Easter, hehe.


  3. V. Lopez
    Dec 21, 2013 @ 21:24:38

    Excellent job! And the LiPo input is very useful, 2 questions: how would the LiPo be protected from overdischarge? and does LiPo mean 3V3 power for the ATtiny? Thanks


  4. ergozru
    Dec 27, 2013 @ 19:58:02

    how to buy it??? i want it!!!


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  6. Joshua
    Jan 03, 2014 @ 10:24:39

    At 20x20mm (or 20mm diameter for the round one) I think TinyDuino may still hold the crown for being the smallest (and has an Atmega328P to boot…)

    That said, Olimexino-Nano is still a very cool product!


  7. Joshua
    Jan 03, 2014 @ 10:42:30

    Yesh, I stand corrected, yours is smaller! Also looks quite usable despite its size.


  8. paulr
    Jan 04, 2014 @ 02:44:33

    Femtoduino ( at 15.2mm x 20.7mm is smaller than 20x20mm though larger than this 85S board. On the other hand the Femtoduno uses an Atmega processor with more memory than the tiny85.

    I can’t quite tell the dimensions of the Digispark but I remember it’s designed that you can cut off the USB plug portion of the board if you don’t need it.

    This board is also very nice and it’s great that more very small boards are appearing.

    What I’d really like if feasible is a bulit-in lipo charger, so that if you connect the board to a USB port with 5V power, the battery charges automatically, and there would be some software monitoring it. That might require the Atmega processor due to code size issues.

    It would also be awesome to have a tiny board based on this cpu:

    That’s an ARM Cortex M0 with 32k of program flash and 8k of ram, in a 2x2mm WLCSP package. I think special PCB fabrication gear might be needed, though.

    The RFDuino ( is also very interesting.


  9. slevon
    Jan 23, 2014 @ 22:47:06

    I like that it comes with a USB connection, thats a feature that most other tiny board don’t have.
    Do you plan to sell it in your store? I’ve had a look and can only find the “ordinary” Tiny85 board (Which I already have here 🙂 )

    Best regards,


  10. Jon
    Feb 10, 2014 @ 02:00:25

    Any news for when this becomes available in the shop?
    Regards, Jon


  11. ivan
    Mar 11, 2014 @ 20:31:19

    I’m quite sure that no Lipo charger is present, despite of the other 85 models. Isn’t it?


  12. juj
    May 30, 2015 @ 01:06:27

    This is so amazing! Got one from ( and it is solving my Arduino dreams. True “computing out of sight”, beats Adafruit Gemma by a long shot. I hope this product lives on for long and keeps evolving even further! Some thoughts:

    – uploading sketches from Arduino seems to be a bit flaky, and the “Eep! Connection to device lost during erase!” message appears a lot. Seems to work fine though with patience.
    – it would be cool to see one day a version that simultaneously allows connecting a lipo and power from usb, and recharge the lipo from the usb when connected. This is similar to what Adafruit power boost pack does: .


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