I recently -- by which I mean probably 6 months ago -- bought a Lenovo T420. The machine is amazing, except on one point: the microphone and headphone jacks are combined. For work, I need to be able to use Skype; it's not my favorite program in the world, but hey, it sort of works when the weather is right and the stars are aligned. However, with the integrated microphone/headphone port, I had a problem: I could not connect a microphone while still using my laptop's speakers. The T420 also includes a built-in stereo microphone, but this did not work correctly under Linux. I needed to make the internal microphone work.

I recently bought an Arduino Uno (thanks in part to SparkFun's free day, thanks SparkFun!), and I have finally gotten around to hooking it up to my main Linux box, which runs Gentoo. Some notes on problems I encountered getting everything working:

Bluetooth is one of the modern wonders of modern wireless technology. Whether you want to talk on the phone through your car or play a game on your Wii with a wiimote, you're using bluetooth. It is wonderful, when it works. When it doesn't, however, then it can be a royal pain.