Garage Door Opener’s History
The first ELECTRIC overhead garage door opener was invented by C.G. Johnson in 1926 in Hartford City, Indiana, but did not become popular until the Era Meter Company of Chicago offered a garage door opener after World War II. A garage door could be opened via a key pad located on a post at the end of the driveway or a switch inside the garage. The electric opener does not provide the actual lifting power to open a heavy garage door. Instead, most of the actual lifting power comes from the counterbalance springs attached to the door. These springs are under tension to lift the garage door via steel counterbalance cables. The electric opener provides only a small amount of force to control how far the door opens and closes. In most cases, the garage door opener also holds the door closed in place of a lock.
The first WIRELESS GARAGE DOOR OPENERS were invented and developed independently by two US inventors, one in Illinois and the other in Washington state. The first garage door remote controls were simple and consisted of a simple transmitter (the remote) and receiver which controlled the opener mechanism. The transmitter would transmit on a designated frequency; the receiver would listen for the radio signal, then open or close the garage, depending on the door position. The basic concept of this can be traced back to World War II. This type of system was used to detonate remote bombs. This technology saw its end when people began to notice that when they opened their garage door, they opened their neighbor’s garage door as well. While the garage door remote is low in power and in range, it was powerful enough to interfere with other receivers in the area.
The second stage of the wireless garage door opener system dealt with the shared frequency problem. To rectify this, multicode systems were developed. DIP switches and used remotes were preprogrammed to one out of roughly 3.5 billion unique codes.
The third stage of garage door opener market uses a frequency spectrum range between 300-400 MHz and most of the transmitter/receivers rely on hopping or rolling code technology.
The fourth stage of garage door opener systems is similar to third stage, but it is limited to the 315 MHz frequency. The 315 MHz frequency range avoids interference from the Land Mobile Radio System (LMRS) used by the U.S. military.
The following standards are used by garage door openers manufactured by LiftMaster:
1984–1993 – 8-12 Dip Switch on 300-400 MHz
1993–1997 – Billion Code on 390 MHz
1997–2005 – Security+ (rolling code) on 390 MHz
2005–present – Security+ (rolling code) on 315 MHz
2011–present – Security+ 2.0 (rolling code) on 310, 315, and 390 MHz
Partially from Wikipedia. Photo of A residential garage door opener.