Harps have been in use for many years. In fact, they have outlived a number of musical instruments that fell into the musical black hole. You see, many archaic instruments could not keep up with the changes in music theory and practice. They simply could not play the new musical notes. The pedal harp is actually the latest in harp technology that kept the harp from falling into this same hole.
The pedal harp came about as a result of the change in music throughout history. With the time, music began to get more complicated. Many instruments did not have the capacity to play the musical notes that started to show up. The original harp did not include sharps or flats.
As music began to include these sharp and flat notes, the logical conclusion seemed to be the addition of strings placed in between the original ones. Though in theory this was a great idea, it was not very practical.
Before pedal harps were invented, some harps were built that included extra strings. This did not work out because the strings would have to be so close together that playing the harp became very difficult. Some harps even tried adding the extra strings at a diagonal, but the solution did not lay in extra strings.
The pedal harp is not the only modern harp that can play sharps and flats. The lever harp can also play sharp and flat notes. In fact, the lever harp came before the pedal harp. It uses levers and is commonly known as a folk, celtic, or Irish harp.
The pedal harp is different from the lever harp because it does not require use of the hands, but is used by pressing pedals with the feet. The pedal harp allows you to sharpen or flatten all occurrences of a single note. For instance, by pressing the G note's pedal all the way down, all of the G's then become sharp. Each note has a pedal with three positions.