Editing Computer mouse (section)

=== Stationary trackballs ===
The [[trackball]], a related pointing device, was invented in 1946 by [[Ralph Benjamin]] as part of a post-[[World War II]]-era [[fire-control system|fire-control]] [[radar]] plotting system called the [[Comprehensive Display System]] (CDS). Benjamin was then working for the British [[Royal Navy]] Scientific Service. Benjamin's project used [[analog computer]]s to calculate the future position of target aircraft based on several initial input points provided by a user with a [[joystick]]. Benjamin felt that a more elegant [[input device]] was needed and invented what they called a "roller ball" for this purpose.<ref name="Copping_2013_Benjamin" /><ref name="Hill_2005_Benjamin" />

The device was patented in 1947,<ref name="Hill_2005_Benjamin">{{cite web |title=RALPH BENJAMIN: An Interview Conducted by Peter C. J. Hill |editor-first=Peter C. J. |editor-last=Hill |publisher=IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc. |date=2005-09-16 |type=Interview |series=Interview #465 |url=http://ethw.org/Oral-History:Ralph_Benjamin |access-date=2013-07-18}}</ref> but only a prototype using a metal ball rolling on two rubber-coated wheels was ever built, and the device was kept as a military secret.<ref name="Copping_2013_Benjamin">{{cite web |title=Briton: 'I invented the computer mouse 20 years before the Americans' |author-first=Jasper |author-last=Copping |publisher=[[Telegraph Media Group|The Telegraph]] |date=2013-07-11 |url=https://www.telegraph.co.uk/technology/news/10174366/Briton-I-invented-the-computer-mouse-20-years-before-the-Americans.html |access-date=2013-07-18}}</ref>

Another early trackball was built by [[Kenyon Taylor]], a British [[electrical engineering|electrical engineer]] working in collaboration with Tom Cranston and Fred Longstaff. Taylor was part of the original [[Ferranti Canada]], working on the [[Royal Canadian Navy]]'s [[DATAR]] (Digital Automated Tracking and Resolving) system in 1952.<ref name="Vardalas_1994_DATAR">{{cite journal |doi=10.1109/85.279228 |title=From DATAR to the FP-6000: Technological change in a Canadian industrial context |date=1994 |author-last=Vardalas |author-first=J. |journal=IEEE Annals of the History of Computing |volume=16 |issue=2 |pages=20–30 |s2cid=15277748 |url=https://ewh.ieee.org/reg/7/millennium/fp6000/fp6000_datar.html| issn = 1058-6180|url-access=subscription }}</ref>

DATAR was similar in concept to Benjamin's display. The trackball used four disks to pick up motion, two each for the X and Y directions. Several rollers provided mechanical support. When the ball was rolled, the pickup discs spun and contacts on their outer rim made periodic contact with wires, producing pulses of output with each movement of the ball. By counting the pulses, the physical movement of the ball could be determined. A [[computer#Vacuum tubes and digital electronic circuits|digital computer]] calculated the tracks and sent the resulting data to other ships in a task force using [[pulse-code modulation]] radio signals. This trackball used a standard Canadian [[five-pin bowling]] ball. It was not patented, since it was a secret military project.<ref>{{citation |url=https://books.google.com/books?id=CrzgS5SoMzcC&q=intitle:%22Pioneers+in+Canadian+Electrical+Manufacturing%22 |title=Ferranti-Packard: Pioneers in Canadian Electrical Manufacturing |author-first1=Norman R. |author-last1=Ball |author-first2=John N. |author-last2=Vardalas |publisher=[[McGill-Queen's Press]] |date=1993 |isbn=978-0-7735-0983-2}}</ref><ref>{{cite web |url=http://www.ieee.ca/millennium/fp6000/fp6000_datar.html |title=FP-6000 -- From DATAR To The FP-6000 |work=ieee.ca |access-date=2021-06-28  |archive-date=2019-04-04  |archive-url=https://web.archive.org/web/20190404053248/http://www.ieee.ca/millennium/fp6000/fp6000_datar.html |url-status=dead }}</ref>