I am looking for a way to control the speed of either a DC motor or a servo using a -10V to +10V analog voltage signal. This type of control seems to be pretty standard for industrial servo amplifiers, but I can't find a cheap one (to run hobbyist sized motors.)
Thanks. Unfortunately I don't really want to sink the time time and into designing the amp. I found this:
**broken link removed**
but it is still over kill (I don't really have a strict motor requirement because its just for controller testing.) I don't want to spend more than 25 dollars, because I need 5 or them.