Handmade/Homemade Board: "My Arduino III"

I love homemade boards, and this layout is by Carlos Rodrigues is lovely!  From Flickr:

Construir o meu próprio Arduino, fase 3: alguns upgrades.

Tem agora melhor protecção contra ruídos na alimentação, reset automático ao iniciar um upload, protecção contra excesso de corrente no USB, e o bootloader do Arduino Uno.

Translated by Google:

Build my own Arduino, phase 3: a few upgrades.

You now have better protection against noise on power, automatic reset to start an upload, protection against excess current in USB bootloader and Arduino Uno.

[diagrams]

New Arduino Micro

Adafruit did a lovely job with the Arduino team on the new official Arduino Micro. Everything is tiny, with a smaller ATmega32u4 and parts on the top and bottom, some the smallest components available-- seriously micro! It's available now for $25.

Pantry Light Demo

The pantry light is installed and working perfectly: I'll post code and circuit details eventually, not much to it though.

555-Based Dimmer 3D Circuit

I built this 3D, freeform circuit as a test project. I've seen a few lately and love the way they look, and after making this circuit, I'm excited about this method as an alternative to point-to-point soldering or etching for small, one-off boards.

It's a dimmer circuit: a 555-timer-based PWM generator driving a high power MOSFET.  I kept it simple and focused on a method, not on making anything particularly fancy.

Here's a video walk-through of the circuit:

I edited a schematic for a board I'd built earlier, adding a scrounged 10k audio potentiometer with switch.  The parts list was short:

• 10k potentiometer with switch,
• 2 2-pin screw terminals (input and output),
• NE555 8-pin chip,
• fat npn MOSFET,
• 2 1N4148 diodes,
• 2 capacitors: .1uF and 1uF,
• 330 ohm resistor

The first step was the Eagle board layout.  With air-wires I moved things around for a while to get things close, and routed and rerouted a few times before setting some guidelines:

• Put the major components where you want them first.
• Pack the rest of the components in paying attention to keeping traces short.
• Small 2-lead components can fit later, with one lead overlapping its signal, the other reached by a branch made from its lead.
• Lay out a few long traces that hit the most pins and cover the most ground first.  Try to get those traces in a straight line or aligned in an L- or S- or U- arrangement, more or less.
• Avoid branching, unless the branch can be a component's lead.
• Small kinks and zig-zags are OK and may be built with straighter wire segments later, with pins bent to get where they need to be. 
• Don't think much about top/bottom layering and about crossing lines.  There will be room to cross a wire here or there.  Try not to cross, but you can worry about top and bottom later.

Then on to building, which breezed by.  Pre-bent wires made it a straightforward, by-numbers sort of thing, and I used the components' leads instead where I could,  reducing the number of parts.  Building notes:

• Print out a sheet to see the circuit different ways, to use as a pattern.  Run the same sheet through the printer, taking advantage of the print options:
• Aligned top center, scale 2 or 3 (what will fit), with all layers drawn.
• Aligned lower left, scale 1, with all layers,
• Aligned lower right, scale 1, just the traces.
• Note: also print scale 1 mirrored versions too, of all layers and traces only, to see things from the bottom, which is how things are soldered.
• In the trace-only print-out, number the longest traces to make wires for them.
• Strip a length of stripped solid-core wire for each long trace.  Bend them to shape with pliers, clipping to length, using the trace-only print as the pattern.
• Small kinks in the pattern don't generally need to be bent-- wires and pins will bend during soldering.
• Clip leads after soldering, unless it has to butt up as a T.  It's easy to clip after soldering, and wires can shift during soldering.

I kept it simple and methodical so I could scale it up to bigger circuits.  I have to say that the result surprised me in how quickly and easily the board came together.

I'm looking forward to using this on a few other cicruits, maybe a PIC-based USB-serial converter, or a multichannel MOSFET-based switcher or SSR or... good stuff from this :) Then there's the question of how to mount this, or cast it in some material.

3D Circuit Construction

Rupert Hirst's amazing resin-encased headphone amplifier is a work of art and shows a novel (to me) way of building a circuit without any mounting board. His buildlog shares many great details, especially about the casting process.

Mats Engstrom has shown a few 3D circuits lately too: a Little Wire programmer circuit built boardless with SMD components (at left) and encased in resin, and a Freeformed Nixie Tube clock with a beautiful radial design inside a box-like frame.

Kimio Kosaka files his incredible "Arduino Skeleton" board under "O'baka Project" which he says: "means a stupid project. This project is to make things which is not art and which is not usable. Now, I am making Arduino skeleton by using steel wires." Hmm, they look like usable art to me! Maybe a mis-translation. He lists instructions:

How to make.
1. Design single side PCB by EAGLE-CAD. (Base circuit is Metaboard)
2. Print out this PCB pattern.
3. Trace this PCB pattern by steel wire. (0.46mm in diameter)
4. Soldering

   I used a flux of the strong acidity for the steel wire soldering.

His "One Chip Arduino" has no board either, stressing economy.

I find more examples the more I look, like this 3D alarm clock, video about using a CD as a circuit board, and Make: uses the tag "freeform" for freeform circuit layouts on its blog.

These inspired me to make one of my own, which turned out to be a faster, easier, cleaner way to make a simple 1-off circuit than home etching or point-to-point soldering, if the process is refined.