Learn how garage door opener clickers work, and how features have improved over the years to bring more security to your home.
A garage door opener clicker is a simple remote device that transmits a radio signal to your garage door opener receiver (the unit in your garage), telling it to operate your garage door. The technology of the clicker has advanced over the years to provide additional security, which has led to the development and popularity of other remote entry devices such as key fobs that operate the locks on your car doors.
The First Garage Door Openers
Garage door openers first made their appearance in homes in the 1950s. They were very simple devices. The clickers sent out a single signal, and they all operated on the same frequency. This simplicity caused major security problems as garage door openers gained popularity. Almost any garage door opener clicker would operate any garage door opener. Manufacturers had to find a way to provide their customers with home security.
DIP Switches Add Security
Manufacturers added security to garage door openers by the 1970s by varying the frequency and signal. The radio frequency varied between models and manufacturers. The addition of DIP switches helped vary the radio signal. A DIP switch is a series of tiny switches attached to a circuit board. Each tiny switch can be positioned up or down to create many unique combinations. On a typical eight-switch DIP switch, 256 combinations are possible. A DIP switch was added to both the garage door opener clicker and receiver. The switches are usually located in the battery compartment of the clicker and on the back of the receiver, and can be changed manually. The DIP switches in the receiver and the clicker must be set the same for the clicker signal to be accepted by the receiver. This prevents neighbors from accidentally opening the wrong garage door, but only provides a minimal level of security. Thieves can use radio scanners to read the radio code the clicker sends to the receiver. Since the signal sent by the clicker is always the same, they can simply retransmit the code to open your garage door.
The Modern Garage Door Opener
Modern garage door openers use computer technology called rolling code generation to provide additional security. Both the clicker and the receiver contain a small computer chip with identical code generators. After you press the clicker button and operate the garage door, both the clicker and the receiver generate a new identical code and save it in memory for the next operation. If the receiver detects a radio signal that matches the saved code, it operates the garage door. The number of possible codes is almost infinite (about one trillion for a forty-bit system).
With this rolling code generation method, what happens if you push the button on your garage door opener clicker when out of range of the receiver? The code in the clicker will change to the next generated code, but the code in the receiver will remain the same. Of course, manufacturers have taken measures to ensure that your garage door opener will still work. The receiver is programmed to scan ahead and accept a set number of the next possible codes. For example, if you press the clicker button five times while away from home and then press it in the range of the receiver, the receiver will not recognize the fist code received and will start to check a set number of code generations ahead for a matching code. In this case, the transmitted code will match the sixth code, and the garage door opener will operate. The receiver usually accepts over 200 code generations ahead, so you are safe provided you do not press the clicker button excessively before using it to open your garage door.
