Swing and Sliding
Generally, gates can either swing or slide open. Sliding gates open by moving out toward the sides of the gate in parallel motion, ending in predetermined slots. Sliding gates require some sort of ground-based pulley system or sheath that the gates can slide in and out of. These are simplest types of gates for motors to operate. Swing gates swing inward or outward to open. The swinging motion is often harder for motors to control, so larger motors are needed that can produce more power. Swinging gates are used when there is not enough room for a sliding gate or when a swinging gate looks better for cosmetic reasons.
Button and Detection
With electric gate openers, there are generally two ways the gate is told to open or close. The first way is by remote, the same way a garage door works. A remote sends an infrared or radio wave signal to the motor of the gate, which then opens, and closes again when a second command is given. Detection systems use either infrared beams or pressure plates to detect when a car has pulled up to the gate, which may then open or simply be activated to wait for a further command.
If you are unsatisfied with an electric gate hooked up to the power grid, you may prefer a battery-based gate instead. These gates have more flexibility in terms of placement, since the battery can be based nearly anywhere and cords run to the gate motor for operation. The battery will need to be recharged periodically, however, and eventually replaced.
Many newer automatic gate openers use a solar system to generate electricity for the gate. Solar panels are constructed near the gate, and sunlight is turned into electrical energy that is stored in a battery. This energy is used to open and close the gates, while the battery does not need to be manually charged or replaced.
Some people may choose to switch from an automatic gate opener to a manual gate. While you have to step out of the car and open these gates by hand (or have someone else do it for you), these gates also preserve all their aesthetic qualities and are not marred at all by motors, cables, traction devices or solar panels. If this is preferable, you may also want to consider a ground-based electrical system, which costs more but does most of its work underground, leaving the gate mostly in its original condition.