Electronic – arduino – Proper soldering iron wattage for working with uP scale electronics

Last time I looked the Sparkfun Speakjet shield did have stackable headers? Anyhoo aside from that moot point- It depends on how permanent your project is.

If you want to be able to use the Arduino again with different projects or shields - it's definitely recommended you get some stackable headers because of the cheap cost and ease of use.

If the project is relatively permanent and you don't intend on using the Arduino again in another project, soldering the wires on might be better for you, it will be cheaper in the short run and will be affective for making good connections - it's just fiddly to do and not the most professional looking way of hooking stuff up.

As far as your question about soldering the gyro sensor to the aeroquad shield goes, if you look a the tiny picture on their website, in the center of the board there is a region marked "gyro". You'll take the single inline pin strips (also pictured) and break off 7 pins as a group. Then you'll solder the short end into the gyro board. Then (unfortunately) it looks like you'll have to solder the gyro board into aeroquad.

As far as shields go, in my experience (Arduino Duemilanove) the spirit behind the shield concept is to allow them to stack up. The aeroquad "shield" doesn't appear to allow this, so I imagine you'll want to get single inline headers and solder them into the aeroquad so you can plug in the Arduino.

So if you want to add more breakout boards, the general procedure would be to get the headers with the extra long pins, and put those through your protoboards so that other shields can stack on top of them. This allows everyone access to the pins in the Arduino that they need.