【導(dǎo)讀】隨著電子技術(shù)的飛速發(fā)展，傳統(tǒng)彈子鎖的缺點(diǎn)漸漸被放大，社會(huì)對(duì)新式電子密。碼鎖的需求越來(lái)越大，前景廣闊。本課題主要采用單片機(jī)完成了一套具有按鍵輸入、顯示、解鎖、報(bào)警及密碼修改等多種功能的電子密碼控制系統(tǒng)。據(jù)有關(guān)資料介紹，電子密碼鎖的研。究從20世紀(jì)30年代就開(kāi)始了，在一些特殊場(chǎng)所早就有所應(yīng)用。研究這種鎖的初衷，就是為提高鎖的安全性。由于電子鎖的密鑰量（密。碼量）極大，可以與機(jī)械鎖配合使用，并且可以避免因鑰匙被仿制而留下安全隱患。電子鎖的種類繁多，例如數(shù)碼鎖，指紋鎖，磁卡鎖，IC卡鎖，生物鎖等。實(shí)用的還是按鍵式電子密碼鎖。碼器的生成為軟件方式。隨著社會(huì)科技的進(jìn)步，鎖已發(fā)展到了密碼鎖、磁性鎖、電子鎖、激光鎖、聲控鎖等等。的安全系統(tǒng)是其中的組成部分，因此研究它具有重大的現(xiàn)實(shí)意義。本系統(tǒng)由24C02和12864顯示的電子密碼鎖設(shè)計(jì)單片機(jī)系統(tǒng)、4×3矩陣鍵盤、12864顯示。防止他人的非法操作。示甚至添加遙控控制功能。

　　

【正文】 e play, unless the teams agree otherwise. Orange is the regulation color. At all levels of play, the home team provides the ball. Inflation of the ball is based on the height of the ball39。s bounce. Inside the covering or casing, a rubber bladder holds air. The ball must be inflated to a pressure sufficient to make it rebound to a height (measured to the top of the ball) of 4954 in ( m) when it is dropped on a solid wooden floor from a starting height of 6 ft ( m) measured from the bottom of the ball. The factory must test the balls, and the air pressure that makes the ball legal in keeping with the bounce test is stamped on the ball. During the intensity of high school and college tourneys and the professional playoffs, this inflated sphere mands considerable attention. Basketball is one of few sports with a known date of birth. On December 1, 1891, in Springfield, Massachusetts, James Naismith hung two halfbushel peach baskets at the opposite ends of a gymnasium and outlined 13 rules based on five principles to his students at the International Training School of the Young Men39。s Christian Association (YMCA), which later became Springfield College. Naismith (18611939) was a physical education teacher who was seeking a team sport with limited physical contact but a lot of running, jumping, shooting, and the handeye coordination required in handling a ball. The peach baskets he hung as goals gave the sport the name of basketball. His students were excited about the game, and Christmas vacation gave them the chance to tell their friends and people at their local YMCAs about the game. The association leaders wrote to Naismith asking for copies of the rules, and they were published in the Triangle, the school newspaper, on January 15,1892. Naismith39。s five basic principles center on the ball, which was described as large, light, and handled with the hands. Players could not move the ball by running alone, and none of the players was restricted against handling the ball. The playing area was also open to all players, but there was to be no physical contact between players。 the ball was the objective. To score, the ball had to be shot through a horizontal, elevated goal. The team with the most points at the end of an allotted time period wins. Early in the history of basketball, the local YMCAs provided the gymnasiums, and membership in the anization grew rapidly. The size of the local gym dictated the number of players。 smaller gyms used five players on a side, and the larger gyms allowed seven to nine. The team size became generally established as five in 1895, and, in 1897, this was made formal in the rules. The YMCA lost interest in supporting the game because 1020 basketball players monopolized a gymnasium previously used by many more in a variety of activities. YMCA membership dropped, and basketball enthusiasts played in local halls. This led to the building of basketball gymnasiums at schools and colleges and also to the formation of professional leagues. Although basketball was born 22 in the United States, five of Naismith39。s original players were Canadians, and the game spread to Canada immediately. It was played in France by 1893。 England in 1894。 Australia, China, and India between 1895 and 1900。 and Japan in 1900. From 1891 through 1893, a soccer ball was used to play basketball. The first basketball was manufactured in 1894. It was 32 in (81 cm) in circumference, or about 4 in (10 cm) larger than a soccer ball. The dedicated basketball was made of laced leather and weighed less than 20 oz (567 g). The first molded ball that eliminated the need for laces was introduced in 1948。 its construction and size of 30 in (76 cm) were ruled official in 1949. The rulesetters came from several groups early in the 1900s. Colleges and universities established their rules mittees in 1905, the YMCA and the Amateur Athletic Union (AAU) created a set of rules jointly, state militia groups abided by a shared set of rules, and there were two professional sets of rules. A Joint Rules Committee for colleges, the AAU, and the YMCA was created in 1915, and, under the name the National Basketball Committee (NBC) made rules for amateur play until 1979. In that year, the National Federation of State High School Associations began governing the sport at the high school level, and the NCAA Rules Committee assumed rulemaking responsibilities for junior colleges, colleges, and the Armed Forces, with a similar mittee holding jurisdiction over women39。s basketball. Until World War II, basketball became increasingly popular in the United States especially at the high school and college levels. After World War II, its popularity grew around the world. In the 1980s, interest in the game truly exploded because of television exposure. Broadcast of the NCAA Championship Games began in 1963, and, by the 1980s, cable television was carrying regular season college games and even high school championships in some states.