I am starting myself on a simple project to start myself off with. It is dealing with servos and light sensors. The project is to create a small system to retract curtains on a window during the appropriate levels of light. I am having trouble with selecting and finding servos to use. One would need to twist the arm of the curtain, while a second would need to raise the curtain itself. Beyond the raising part, would it be harmful for the servo to just hold it up all day? Any recommendations on servo gathering or how to choose appropriate ones would be nice.
I do believe you would want to modify your servo to rotate continuously, otherwise you won't have enough motion to get the curtain anywhere. I've never done this, but this tutorial seems legit. http://www.acroname.com/robotics/info/ideas/continuous/continuous.html
Below are typical inexpensive large servos. You will need to give more detail on your desired mechanical setup. Google searches for automated blinds and similar should give you some background info on what is available and similar projects.
Hi, Maybe take a look at the servos here: http://goo.gl/in6v7
Look at the details and you will see torque ratings in Kg/cm . You need to experiment with the mechanical design you end up with to find the torque needed. For example, if you have a lever arm on a spool for a cord you are pulling the curtain with, 100g force on a 10cm lever or radium = 1Kg/cm
DISCLAIMER: Mentioned stuff from my own shop...