Sometimes, a simple fix is the best solution. Lacking extra funds for a proper remote-controlled gate-opener after the recent purchase of their farm, redditor [amaurer3210] built one as a birthday gift for his wife.
Supported on pillow block housings, a 10″ wheel is connected to the motor by via a 3D printed pulley and a timing belt turned inside-out to allow for slippage — in case of obstacles or manual opening of the gate. If you’ve ever worked with belts in your builds, [amaurer3210] adds that during sizing he uses a few layers of fiberglass tape as a stand-in for the belt to avoid frustration over final belt size and tension.
The motor is a a cordless SKIL drill motor, perfectly suited to the purpose with its low-rpm, high-torque planetary drive. Making heavy use of his 3D printer, the motor, a homemade wire-wound resistor (to step down the 12V power supply to 3V for the motor), and an eMylo 12V wireless wireless relay cheaply acquired online are all mounted with printed parts — as well as the housings, pulleys and brackets — in ABS plastic to avoid softening in the day’s heat. Perimeter security is maintained via a gate latch controlled by a solenoid wired in parallel with the motor to unlock when the motor starts.
A bungee acts as a tensioner to keep the wheel pressed against the ground while also allowing it to roll over obstacles. The simple ‘hold open until the gate is open and vice-versa’ remote operation completes a build that needs no extra flair to be effective.
Looking to facilitate other outdoor activities around the homestead? How about a remote-controlled lawnmower.