Lifting a gate

Hey all.

So I’m designing a simple gate lift (think model railroad crossing gate), and I’m looking to see which mechanism would be best for accomplishing lifting a “gate” from level to +90 degrees, then back down again.

Specifically, which type of motor would be best in this situation, and which method of detecting position?

At first i was thinking about using a stepper motor for the ability to determine position through the code, but I’m not sure the 12v or smaller steppers have enough holding force to lift and lower the “gate” (it’ll be lightweight balsa, but maybe 18" long).

The next idea I had was a DC gear motor, and mounting a detector behind a circular plate with a small hole drilled into it that coincides with the gate at the proper positions. My only concern there is how to handle stopping the motor without a jolt. I’d rather have the last bit of travel be a graceful slow to a stop.

Last thing I was thinking was using hard stops and detecting when the load of the motor starts to get excessive, then stopping it. Although that seems like putting an unnecessary amount of work on the motor, and it will still have a rather jarring stop.

What’s the best practice for accomplishing something along these lines?


Maybe a rc servo, It is easy to control using the servo library

A servo already has suitable gearing and position sensing built-in, probably good choice - just make sure its torque rating is sufficiently higher than the load to ensure smooth operation.

[ Oh, yes, and counterbalance the gate to reduce the torque needed ]