Servo Question

Cenlasoft

Hi,
I have been searching the net and parallax for a simple method to aquire if the servo is in the left or right position. I came up with something and before I try it I thought I would ask the forum for adivse. I want to take a standard servo and tap the middle connection on the servo's pot. I could use this voltage with sigma delta or an adc ic to give its position. Will this tap interfere with the servo's electronics.
Thanks.
Curtis

StefanL38

Hi Curtis,

An adc-chip has a quite high impedance (input-resistance).

Please tell us what you want to do in the end. I remember that somebody at parallax wrote a program which could read a servo-position right from the 3-pin-header.
But I don't remember its name. There was a video demonstration where a second servo followed the first servo which was driven by hand.

keep the questions coming
best regards

Stefan

Duane Degn

I think this is the thread Stefan is referring to.

http://forums.parallax.com/showthread.php?84991-Propeller-Application-Proportional-feedback-from-a-Standard-Hobby-Servo-(Upda&highlight=read+analog+servo

GeorgeCollins

While that method is cool, its not intended to be used while the servo is pulling something at full power. I think what this guy would need is an encoder on the servo wheel, a switch, at mechanical position's or the type of servo that reports back position. Dynamixel servos can report their position. Some digital hitec servos do this, but I have never seen anyone figure out the communication system they use.

Cenlasoft

Hello,
Thanks for all the good suggestions. I ended up using one IR receiver underneath the servo and two IR emmiters, one on each side of the 180 degree path of the servos. I could then tell if the ping was on the right or left side.
Curtis