https://www.ieee.org/
http://ieeexplore.ieee.org/
http://spectrum.ieee.org/
http://www.instructables.com/
http://stackoverflow.com/
http://makezine.com/
https://hackaday.io/
https://www.edx.org/
http://www.engineersgarage.com/
http://https//www.coursera.org/
https://www.sparkfun.com/
http://www.arduino.cc/
http://elearning.vtu.ac.in/elearning/
http://videos.vtu.ac.in/
http://electronicsforu.com/
https://www.electrical4u.com/digital-electronics/