How to Build an Inexpensive Automatic Gate

Dig a 3-foot hole 12 inches in diameter on either side of your driveway. Mix concrete and pour 6 inches of it into each hole.

Place a 4-by-4 wood post in one hole that reaches the desired gatepost height above the surface of the ground. Use a level to ensure the post is vertical and brace it with scrap lumber. Fill the rest of the hole with concrete. Install the second gatepost in the same manner and wait 24 hours for the concrete to cure.

Measure the distance between the two posts and subtract 3 inches. Cut 2-by-4s then assemble them into a rectangular frame as wide as this measurement and a few inches shorter than the final gate height. Screw a diagonal 2-by-4 onto the frame for additional support.

Cut 1/2-inch boards to a width of 4 inches and the desired height of the gate. Screw them to the frame positioned vertically and butted against each other. Mount the gate to one of the posts with hinges -- one hinge near the top of the gate and one near the bottom.

Mount the control box for the gate opener near the top of the post that supports the gate. Assemble the opener and extension tube and bolt them to the same post at a height level with the bottom of the gate frame.

Open the gate and screw the bracket at the end of the extension tube to the gate itself and use the level to ensure the opener arm is perfectly horizontal.

Wire the opener's power cable to the control box, insert the batteries then program the gate's swing range as directed in the opener's manual. Plug the control box into an external outlet on your house to keep the batteries from running out.