Links

Raspberry Pi:

• raspberrypi.org: The official site

Arduino:

• arduino.cc: The official site
• osepp.com

OpenCV:

• opencv.org: The official site
• pyimagesearch.com: Adrian has a site full of information on OpenCV complete with guides for bringing up OpenCV on the Raspberry Pi

Learning:

• voidrealms.com: Bryan has a number os useful programming video tutorials on several subjects including QT, Python, C++, etc.
• lynda.com: A good online learning site that covers just about any topic.
• ocw.mit.edu: MIT Open Course Ware with access to MIT’s course material including documentation and lecture videos
• safaribooksonline.com
• nyccnc.com: Good source of info on CNC machining

Parts:

• adafruit.com
• pololu.com
• sparkfun.com
• mcmaster.com
• openbuilds.com

CAD:

• fusion 360
• openscad

3D Printing:

• Octave Systems
• Tiertime
• Zortrax.com

Fun and Informative:

• Vi Hart: Fun videos on math, music, etc.
• numberphile.com: Short math videos introducing a number of fun and interesting math topics.