Hi guys!

I am new to Arduino and am currently working on a project which will open a door using a servo motor. The one I have is too small and I think it will not get the job done (micro servo). I was wondering if anyone here knows what type of servo I should use, and anyone other advice (will arduino be able to fully power the servo?).

I will be using the servo to power a mechanism that pulls down the door handle.

Thank in advance for the help :slight_smile:

A bigger servo?

You need to measure the torque needed to turn the handle and then get a servo that has greater torque.

Torque is measured in Newton metres (or lbs feet). For example a force of 9.8 Newtons (1 Kg) acting at the end of a 1 metre lever is a torque of 1 Nm. It would be the same as 2Kg acting at a distance of 0.5 metres. Hanging a weight on the door handle and measuring the distance from the centre of rotation will give you an idea of the torque. Assume a substantial margin of error.


You may want to consider using a different motor. There are many high torque, inexpensive, small dc gear motors available to use in lieu of a pricey high torque servo. - Scotty

Hobbyking has a large selection of different size servos available when the amount of force to operate the latch is determined.

You might look for car electric locking servos, they should only be about 10 each