smallest arduino board?

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

Who needs a board? :slight_smile:

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!

Still using the internal oscillator, though?

No, both of them have 16 Mhz ceramic resonators.

Here's a schematic for the second one.

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

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

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.

I avoid drying to use it as a solder pad (I use the copper pads on the board instead), but I have noticed that solder likes to flow over the traces if I use a little too much. Also, if I have to remove any solder, the desoldering braid usually picks up some of the circuitwriter material, and I have to re-apply (which can be difficult with components soldered as tightly as in this project.

Even so, the stuff works surprisingly well. I wouldn't use it for production, but it's the best thing by far that I've found for making a circuit board without waiting (and paying) for a real PCB to be manufactured.

Its also great for hacking existing circuits. I used it to modify my ftdi board to output 5v (right before they took my advice to add a solder jumper for that purpose ::slight_smile: ) and my breadboard power supply to add an unregulated output.

geez, live and learn. I've been bent over my perf-board soldering in twists of wire to join comonents when I have a fine new jar of wire glue I could have tried! Tomorrow for sure.

By the way, could you find a way to get a clearer picture of the board? Do you have a scanner? Sometimes they can do a nice closeup.

The pictures for the second one weren't that bad, where they? I thought about trying a scanner, but I didn't think to take pictures before everything was soldered-in and working, and the wire wrap pins stick out too far for a scanner to be useful.

I decided to get a couple of these made by BatchPCB, and they just shipped out from their facility, so I should have those to show off in a couple of days.

New picture time!

I've made some minor modifications since I ordered these, mostly playing with the fill geometry and silkscreens, and adding a solder jumper for disabling auto reset and an icsp header. The green LED is the standard D13 indicator. The blue one is a power indicator, but it uses D13 for a ground so that it's easier to discern whether the D13 led is on (they can't be on at the same time). The bottom fill is ground, the top one is +5V. The board is two inches long, and the ftdi header sticks out an additional 1/4 inch.

Oh, and any warping in the photos is a side effect of trying to avoid blurriness.





I love how you managed to fit a bunch of components under the socket. Great use of space!

Here are a couple of examples of how easy it is to make projects on a breadboard with these.


breadboard programmer


breadboard POV device

I rather like the idea of using a WW socket and putting components on the board UNDER the socket as well as using the socket pins themselves for plugging into the next "layer" of circuitry.

VERY nice thing.. any chance it will be buyable one day?

It's not difficult to solder (no SMD). If there's enough interest, I could do a run and put together some kits. Anyone else interested?

i'd be happy with the PCB alone...

It's designed for a pretty specific list of parts. If you don't get the same ones, they likely won't fit, especially the caps and resonator under the chip, and the leds on the bottom of the board. Some of these clearances are less than a millimeter. I could give you a list of part numbers, but if I'm going to distribute the boards, distributing kits of parts to go with them will make things easier for everyone.

I got the extreme-closeup problem solved. Now you can see how bad my soldering is... and that I accidentally soldered the sockets in backwards. Here are a few more photos (I was having fun playing with my new toy):