Some Simple Lessons for the Arduino Hacker Who Started As a Programmer

To the software hacker with no experience in electronics, working with an Arduino poses some problems. The programming will seem like a breeze. The breadboarding is straightforward. But practical, deployable electronics pose some problems that software programming does not prepare one for.

• Packaging is difficult and requires creative engineering. Essentially every connection becomes a potential point of failure. Wires break. Solder joints look good but don't actually make good connections. Wires proliferate and strangle the beauty of the project.
• Power management is tricky. Batteries require yet another set of connections and are physically heavy. They must generally be packaged, either together or separately, with your project. Their lifetime in any given application is harder to predict than a software programmer typically imagines.
• PCBs >> Soldering >> Breadboards.  Breadboards are great for prototyping, but terrible even for demoing for more than about an hour---they are very delicate, and once a wire is pulled out it takes a long time to figure out how to replace it. Soldering is a major step up in ruggedness, but error-prone for the beginner. I have not yet sent out a schematic to have my own PCB board made, but I now understand why people do, and why there are so many "breakout boards" at Sparkfun. PCBs are another step up in ruggedness and ease of use (and another step down in terms of mutability.) As your design stabilizes, there is a natural progression toward ruggedness and away from changeability.
• In my limited experience, success depends just as much on methodical testing in hardware as it does in software, if not more. Breadboards seem to make testing easier because they give you places to put your multimeter probes. 
• You will end up using your basic software debugging skills, such as proper logging sent through the serial interface back to the computer, just as much in Arduino programming as in pure software, if not more.
• Be gentle and forgiving with yourself. A lot of things can go wrong in the construction of even simple circuits. To be successful, you will have to tolerate this frustration and treat yourself as you would a child that you are mentoring.