Reddit mentions of Practical Arduino: Cool Projects for Open Source Hardware (Technology in Action)

OK. ModernRonin did a great job. Read his first. Also I'd like to put out the theory that you didn't receive many replies on /r/programming because that is typically a forum for high-level programming, not down-in-the-metal like this.

I've done this plenty of times, and let me tell you from experience, it can be done on the cheap, and pretty easy. Where ModernRonin provided specific answers, I'll try to provide examples of how it might work.

Something like this:

Temp Sensor --> Sensor control board --> PC.

The link between temp sensor and the board is probably I2C (eye-squared-see) or serial port. If it's serial port, you can technically skip the control board directly to the PC. If you're PC doesn't have a serial port (a 9-pin port that looks like a monitor plugin), then you'll have to buy this, which provides a serial port over a USB connection. If you manage that, then you can move on to adding other sensors to the control board. Typically, these extra sensors will all communicate with the control board, which then relays the data all at once to the PC.

Dont' worry about accessing ports, concentrate on the connections (I2C or USB? Serial or Xbee?), then learn how to access what you have.

Start with the control board, I'd recommend something pre-built like an adruino. Then build your own after a month or so. It's so easy you'll never believe it.

"Choosing" ports won't be an issue, each has a purpose, and typically you won't have a lot of flexibility.

Accessing ports is easy. Start with a terminal program. Realterm is the shit. Be friends with it. It'll dump anything coming in over a serial port, which makes debugging really easy.

Most programs will handle accessing the port for you. However, if you want to build your own program (and you will, probably), you'll have to learn how to do this with code. Luckily, libraries will exist to help you, and you won't be inventing anything so much as tweaking pre-existing examples.

Now the hard part is getting the control board set up. This is where people get frustrated and give up. That's why I strongly recommend paying money for this part. The control board will probably be something like an ardruino. I prefer using Microchip's sample program, which gives you access to cheap chips (but you have to know something about laying out a board).

Once you get this down, you can start building your own sensors if you want. Most control boards will have ADC and DAC which will help you with that. However, you probably will NEVER have to build a sensor.

OK. now a list of literature to get you started.

Programming Interactivity

making things talk -- the BEST book for beginners. I loved this book. If I still had my copy I'd mail it to you right now.

Practical Ardruino

And web sites:

Sparkfun -- hobbyist electrical engineering with tutorials

Microchip -- sign up for their free samples when you want to build your own boards

http://www.arduino.cc -- Excellent Beginner Boards

http://beagleboard.org -- Higher level control board, suitable for larger (but still small) embedded projects

Digikey -- catch-all supplier of all things electrical

Oh finally, do send me an msg if you have specific questions.

The book "Practical Arduino: Cool Projects for Open Source Hardware" is a great learning resource for beginners to get started with useful Arduino projects.