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[on:]

I was annoyed by how breadboard-unfriendly all of the arduino boards I could find were (even the nano covers up two extra rows of holes), so I decided to see how small I could get one. I also did not want to use any smt components because my soldering skills are nothing to write home about.

This is what I came up with. I used a wire wrap socket to connect the atmega168 pins directly to the breadboard, and used a piece of perfboard with circuitwriter traces to put the external components in the space under the chip. The schematic is very similar to the dorkboard, but it uses an ftdi header (works with my 5V-modified FTDI basic breakout from sparkfun) for programming.

The board fits over the gap in a breadboard without taking up any more space than a bare atmega168, and the total footprint of the board is only .18 square inches more. It does not have a reset button or on-board power regulation, but I've been playing with the design in Eagle and I think that if I extend it out to two inches and don't have to draw the traces by hand, I can make it feature-equivalent to sparkfun's arduino pro boards.






Sorry for the blurry pictures. I don't have a macro lense, and this thing is small.

[Reply #1 on:]

I think it is still bigger then the arduino mini pro from sparkfun.  you can probably beat that device in size if you go with an smt package for the mega168 without power.

Nice board though

[Reply #2 on:]

The pro mini is .7x1.3 (covers 3 rows on a breadboard), that's .91 square inches. This one, at its widest, is .6x1.7, but the footprint is only .74 square inches, so I suppose it depends on how you measure. This one certainly leaves more space available on the breadboard.

[Reply #3 on:]

Cool!

Smallest DIP based Arduino I've ever seen. Do a writeup on the playground?  :

[Reply #4 on:]

I've been playing with this design for a RRBBB, but it's clear I have slightly different goals (I was less interested in breadboards and more in "runtime board" like functionality with pads to attach to.  And I was less worried about the (relatively large) SMT components on the bottom, or being able to "easily" attach a programming cable.)
http://lh3.ggpht.com/_NOmmtpdLD5M/SeTwlLO-MvI/AAAAAAAACeo/Qhf-Lote4bs/RRBBB.png

[Reply #5 on:]

Did you mean to connect AVCC to ground?

Edit: oops, misread it, it's the pad next to AVCC that's connected to ground. That makes a bit more sense...

[Reply #6 on:]

Sparkfun pro mini and a 28 pin dip socket.

For reduced size on a breadboard smt isn't going to help that much. The smt mega168 is about the same width as a dip socket and you need extra space to break out the pins.

[Reply #7 on:]

Don't forget this one, from the guy who sorted out the serjtag package:


Who needs a board?

[Reply #8 on:]

Version 2!

This one adds a voltage regulator, a reset button, and a few other minor changes. It has everything the Arduino pro mini has except the power indicator led (not enough room to hand-route the 5V line). I also moved everything to the top of the board, except for the led, which makes soldering easier. The board is 2 inches long, .9 square inches.







Better photos too!

[Reply #9 on:]

Still using the internal oscillator, though?

[Reply #10 on:]

No, both of them have 16 Mhz ceramic resonators.

[Reply #11 on:]

Here's a schematic for the second one.

[Reply #12 on:]

what are you using to draw those traces on the protoboard?

[Reply #13 on:]

I used a CircuitWriter. It's a pen that writes with a conductive polymer. It's great for turning perfboard into a psuedo-pcb.

[Reply #14 on:]

Once you've written a trace with that pen, can you solder onto it (better than soldering onto the bare fiberglass of the protoboard)?  I don't think I'd trust an ink trace, but it might be a handy soldering aid if that works.