Instructables user [dustinandrews] just took the wraps off his latest creation, a DIY Arduino Pro Mini clone.
Actually, to call it an clone is technically incorrect – while he aimed to produce a tiny Arduino-compatible board, his goal was not to replicate the Mini’s design. Instead, he developed a 1” x 1” board from scratch, covering the construction process in great detail.
When you are working with components this tiny, the only reasonable way to get things done is via solder reflow. He walks through the steps he took to produce the board, which should be enough to guide those doing reflow for the first time through the process without too much trouble.
The end result looks pretty nice, and when he puts it up side by side against the Arduino Pro Mini, his board can definitely hold its own. While his design lacks an on-board power regulator and reset button, he does provide two more analog I/O pins than the Mini, along with several other enhancements.