Civil War General William Tecumseh Sherman is credited with the quote "War is Hell." While there are many downsides to any war, in some cases the technology invented to aid in winning the war was ultimately used after the war for non-military purposes by the public to improve life.
One such example is "night writing." French Captain Charles Barbier, in the early 1800s, tried to develop a method military officers could use to read messages and orders in the dark while in battle. Lighting a torch, or even a match, to have enough light to read the message could very well alert the enemy to their whereabouts. Barbier developed a method of reading in the dark he called "night writing." The system consisted of a series of 12 raised dots, each arranged in a different pattern for various sounds in the language.
To test the system out, he found a 13-year-old blind boy and taught him how the system worked. The boy struggled to learn the system but ultimately failed. It was just too complicated to learn. Barbier gave up on further development of his "night writing" system. The boy, however, did not give up. Rather, he spent 2 years refining the system and ultimately cut the number of dots down to only 6, and instead of each grouping standing for various sounds in the language, he made each series represent one letter of the alphabet. His "new" system spread widely - and is still in use today. The boys name? Louis Braille.
Another example of technology originally developed for military purposes and later used for a non-military purpose centers on World War II. The United States had more military personnel in this war than any other in its entire history. Letters sent by military personnel to their family and friends, as well as letters to them, was creating quite a problem due to the high volume of mail. Even an entire fleet of airplanes loaded with nothing but mail could not keep up with the sheer volume. A letter would take weeks, if not months, to be received.
A big meeting was called that not only included military personnel, but also experts in various fields of industry. They were presented with the problem and asked to help solve it. The experts went back home and busily engaged into trying to solve the problem - and they did solve it! First, special cameras were developed to enable high quality photos to be taken - high enough quality to read the text on a hand written page from the negative.