Gadgetboard construction hints

Temperature controlled irons are best, and cost >$50. At many schools, you can borrow or use a nice iron. But several people have managed with $10 15/30 watt switchable irons from radio shack, although they had a harder time getting the solder to flow consistently. Cold solder joints and using too much solder were common problems. Find a soldering howto online if you're new to soldering.

Start with the screw terminals, which are easiest to solder and hardest to mess up. Then do the relays, fuse clips, headers and IC sockets. Then the resistors, then the zeners, then the caps. The bypass caps go on the bottom of the board, right to the appropriate pins. Do the active components (MOSFETS, 7805) last, wearing a wrist strap clipped to the half circle made from a TVS lead which you can see just above the word "Output" at the bottom left of this picture.

(Make the wrist strap from a piece of wire several feet long, stripped several inches at one end and looped around your wrist with a 100k resistor in series with the other end, alligator clipped to the free end of the resistor)

I found that using a tiny dab of hot glue at opposite corners of components that fall out makes them easier to solder, but I've heard that hot glue becomes conductive over time, so I've been using sticky tack instead, which I can remove after soldering the part in place.

Finally, socket the chips, install the jumpers and you're ready to program the MCU.

Make sure to install all the components in the right direction (resistors don't matter), and don't mix up the P and N channel MOSFETs.

When you install the sockets, align the half circle with the half circle in the silkscreen; it'll indicate which direction to put in the IC (although pin 1 is also marked for each one).

Circuit board errata

One customer reports that the Digikey parts list does /not/ in fact ignore the optional parts after the blank line. Check over the list before you place an order to make sure you're getting what you need, and be prepared to make substitutions since Digikey often runs out of particular part numbers.
One of the board photos shows a diode reaching diagonally away from the atmel chip. That was due to an omission in a prototype of the PCB that omitted the +12->ground zener diode.
The 33uF capacitor has been replaced by a 1000uF capacitor, since 33uF wasn't enough to support 12V AC power adapters. The bigger cap is physically a lot bigger, but will lay down on its side; make sure the leads don't short to each other when you place it.