Very Small Arduino


I need to make a very small Arduino to put inside a project.
Could I just solder the components straight to the chip socket as shown in the picture.
If so, have I missed any vital components?
It will be powered by a seperate power supply, as shown in the schematic in the corner.
Also, the chip will be programmed using an uno, so i don’t need any programming wiring.


You want a 0.1uf capacitor between vcc and gnd right by the chip, that's the only thing that leaps out at me. You can solder it straight to those pins, doesn't get much closer to the chip than that!

Does your sketch call analogRead?

Thanks for the input guys.

I'll add the capacitor as you mentioned.

I won't be using analog read on this occasion. I may in the future though, would this require anything different?

Thanks again Paul

Yes. Something connected to AREF. At a minimum, a 0.1 uF capacitor.

Yes. Something connected to AREF. At a minimum, a 0.1 uF capacitor.

I would add this even if you don't plan to use it because you might change your mind or use it for a different project and its not like its that much more work.

Could I just solder the components straight to the chip socket as shown in the picture.

I suppose you could but I don't think I would suggest that. It would work but considering that you have to pull that chip out of the socket a lot it will probably break quickly. My general experience with sockets and ICs is that it takes a bit of finagling to get it out and without something to hold onto it could be very difficult. I would just use a really small piece (like an inch wide) of proto-board. I would be much stronger and probably easier to recreate.

BTW Thanks for figuring this out, I was looking to do pretty much the exact same thing but never took the time to study the arduino schematic and get rid of the non essential stuff.

Also I don't know if they make such a thing but an IC socket with double long posts might be very useful. I'm thinking that if you had the posts sticking down from the bottom a bit you could very easily just plug the whole thing into an uno socket without taking the atmega out of your socket. If you reprogram things and test new code as much as I do that could be nice just to save time. But I'm not sure if you would get any weird hardware interactions between the uno board and the stuff you soldered onto you board with this method. Maybe someone else can say if that would work or not.

Also I don't know if they make such a thing but an IC socket with double long posts might be very useful.

Yes they do, they are called wire-wrap sockets. Cut to whatever length you require.

Those look perfect, I’d cut them a bit shorter than that though. And Colaboy when you finish i’d love to see your handy work if you wouldn’t mind posting a picture

With surface-mount chips you can fit an Arduino into one square inch, if that's small enough for you:

Here is the kickstarter for the 1 sq inch Ardunio from above

Thought I’d give one of those try, design wise . 1" x 0.9".
Need to find a small 16 MHz xtal in eagle still …

Unless you need the clock to be very accurate, you can use a 3-terminal ceramic resonator instead of the crystal and 22pF capacitors - this will save you some space.

The 1A 7805 regulator is overkill unless you are driving a lot of other components from the 5v supply. The 78L05 delivers up to 100mA - enough for the mcu and several LEDs - and comes in a smaller package.

If you can spare the space, I would include the 6-pin ICSP header so you can reprogram your mcu in situ.

I do not know if this is an inappropriate post here. If so I apologise.

I have used several of these tiny Ardweeny devices

They cost less that $10 and the form factor is only a tiny bit larger than the chip.

There's also a handy trick to program them without buying the special adapter

I hope this helps.

I like the crystal for accurate comms. Just couldn't find the correct footprint in eagle. The one I used was just a hair too long. I could turn it diagonally I suppose.

I was thinking off board regulator, or power direct from battery.

All the pins that make up ICSP header are also on the headers, using a breakout cable takes care of that. This would be used more as a last step after development - download the sketch & install the part.

Altho I just realized I left Reset off. I'll make the 6-pin header an 8 instead, and catch it there.

I've played with other versions also:

Very cool. Thanks for all those files. I love seeing things like this they look so awesome and jank. You should post a picture of the front of that contraption

I have, here on the forum and also at

This is better, much cleaner.

Wow! Thanks for all the info gang.

Lots to take in and mull over.

I will weigh up my options and decide which way to go.

Thanks again, much appreciated I can assure you.


Any one have any comments? I’m gonna order a batch of boards from itead studio.

Have you looked at the Lilypad Arduino or Seeeduino FILM?

Soldering the appropriate components on a chip socket is probably the easiest way to go if you're not going to be continually reprogramming the ATmega chip. The Seeduino is a little larger than it absolutely needs to be, but it does have the header for a USB programmer breakout board.