- What is Rolling code?
A rolling code (or sometimes called a hopping code) is used in keyless entry systems to prevent replay attacks, where an eavesdropper records the transmission and replays it at a later time to cause the receiver to 'unlock'.
- When Zenith invented the first wireless remote control?
In the mid 1950's, the company probably never envisioned their creation developing so far past the glorified flashlight or noisemakers they once were. Today, with vibrant color touchscreens, Internet connectivity, system automation at the touch of a button and built-in TV guides, the humble clicker has undoubtedly come a long way - towards complexity. Why have remotes developed into such operationally challenging items? With the ever increasing importance placed upon "foolproofing" technology for the masses, it seems as though user interface ergonomics have traveled in the opposite direction. Each time a major component becomes "better", another dozen or so buttons mysteriously blossom on its remote.
- How to Build a Wireless Remote Control?
1. Open the remote control housing and place a push button switch on the side. In the upper right corner of the housing, fasten a 3-volt battery holder. Be sure enough room is available to install and remove the battery.
2. Run a wire from the push button switch and link to the 3-volt battery holder at the negative connection. Attach another wire to the push button switch and lead it to the Meg 1/4W resistor and the NPN silicon transistor. Run a third wire from the Meg 1/4W resistor and attach it to the 22K 1/4W resistor and and the PNP silicon transistor.
3. Position the infra-red LED on the front of the housing. Attach the LED and run wires to both transistors. From the 22K 1/4W resistor, run a wire to the C220.01uF 16v ceramic disk capacitor. Run another wire between the NPN silicon transistor and the ceramic disk capacitor.
4. From the positive connector on the 3-volt battery holder, connect a wire to the PNP silicon transistor. This will allow for proper current flow in a closed circuit. Ensure the push button switch is positioned to "off" and place a 3-volt battery into the holder. Close the remote control housing.
5. Point the remote control at a receiver, making sure the LED on the control is aimed at the LED of the receiver. Push the button and the receiver should power on and off. To adjust the receiver to be programmed, point the remote control and hold down the push button switch. Adjust the pot or taper on the receiver until you hear a click. This links the remote control and the receiver.