what kind of sensor and how to put it on arm joint

hi :)

i'm a beginner here and also in robotic world. please kindly guide me, what kind of sensor i have to add and where should i put those sensors on each joint?

i mean, i want to "teach" the arm like this short video on this teaching arm video on youtube. basically, i have 6 digital servo which is told they can return the value of the angle position, something like 4096 or 360/4096. i'm not sure about this. perhaps if i give a command such:

servo1.writemicrosecond(1000)

it will go to certain angle of 360/4096.

but that's from coding/programming side.

what i want to know is, i want to move the arm by my hand, so i will record the angle position of those 6 servo.

i think servo1.read only read the last value. so if i move the arm by my hand, i really don't have any idea what to do with arduino or what command should i use or what sensor should i use, to capture the recent/current value of the angle position.

i've googling alot, it seems easy but not for me. ::) i've searching through youtube but i don't have any idea if they put any additional sensor on each joint so arduino can read the current angle position.

please kindly give me a direction. any other sensor should i put on each joint? or simply just query the servo? thx in advance :)

Replace you servos with something like this:Servo with feedback.

Paul

thanks paul for giving me the direction and clear path. an analog feedback... it will be very handy beside the digital one.

thanks... i'll catch that servo trick :D