1. Photonics Textbook
SPIE is offering its Fundamentals of Photonics as a free download. If you hanker to learn more about photonics, lasers, optics, optical detectors, and fiber optics then you can either download the various modules from the SPIE Web site or purchase them on CD-ROM from the SPIE's bookstore. Although the material is intended for first- and second-year college students, it's appropriate for anyone who wants to learn more about the field.
2. Data Acquisiton Tutorials
National Instruments maintains a great repository of data acquisition and sensor-related information in its Developers Zone. This month I'm going to highlight its Sensor Fundamentals section where you can find practical discussions of sensor terminology, how to take measurements using thermocouples and RTDs, how to use strain gauges, how to measure pressure, and the basics of how accelerometers work. In addition to the clear and informative explanatory information, there's also a how-to guide that talks you through how to make the desired measurements (using NI's hardware).
3. Amazing Images
Did you know that NASA has teamed up with the Internet Archive to put its public collection of images online? It's true! The collection is found at NasaImages.org and it isn't limited to still photographs, it includes video and audio as well. Go feast on galaxies, aircraft, and amazing shots of the Earth. In addition to the glorious visuals, there's a wealth of associated information attached to each image to help you understand just what you're looking at.