This is one of the best all around sites that I have found. It is titled “The MacTutor History of Mathematics Archive.”
http://www-history.mcs.st-and.ac.uk/~history/
This is an award-winning site that links to all sorts of mathematics information.
http://archives.math.utk.edu/
Here is a history of mechanical calculators with pictures and links:
http://www.xnumber.com/xnumber/mechanical1.htm
Napier’s Bones is an example of a 17th century calculating device:
http://gwydir.demon.co.uk/jo/numbers/machine/napier.htm
Napier:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Napier.html
Babbage:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Babbage.html
Hawking:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Hawking.html