Saturday, 17 April 2010

Arduino on a budget - part 2

I've made good progress with Veroduino - the Arduino clone I'm building on Veroboard™*.

I like to build up complex circuits from pluggable components. They are easier to test, easier to replace, and can often be used in more than one project.

I started by building a pluggable power supply on a small piece of strip-board; it contains a 5v regulator, and includes a bridge rectifier to provide polarity protection.

Next I started on the board that carries the micro-controller. I abandoned my first prototype; the strip-board turned out to be too wide, covering the breadboard pads that connect to the pins of the micro-controller. I didn't feel too bad about that; the reason that I prototype is to discover design flaws early.

I also verified that my mechanical design plugged into the board correctly. It's tempting to use PCB header pins, but they don't play well with this design. They work really well with a two-sided PCB, because the header can be soldered from the top. I don't know any way to do that reliably with strip-board. Luckily Vero make push-through pins for their strip-board, and the two-ended pins work perfectly.

For the final version I'm going to buy an Arduino-compatible component bundle from .:Oomlout:. along with a set of long-pin headers. At £9 that's affordable, and does not cost much more than the micro-controller on its own.

Today is Saturday, so the package will probably arrive on Tuesday. Meanwhile I'll work on version two of the prototype, making do with a Mega8 chip. That will be fine for driving my I2C-based test equipment.

*Veroboard is a trademarked name for a brand of strip-board that is widely used in the UK.

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