Where to buy Rotary Encoders

Hi ^^ I wanna build a pendubot for my university. I decided to use rotary encoders for an absolut angle measurement. But the problem is, i can't find any contactless rotary encoder, does anyone know where to buy them ? I can't use a Potentiometer or sth like that, because of the friction. This is a Pendubot: http://www.youtube.com/watch?v=Wz1t7McSnUg


Not sure if this fits your budget, but these guys make really nice optical encoders: http://www.microesys.com/

They tend to somewhat expensive for hobbyist use, say $50 and up. However if you search out E-bay you can find bargains once and awhile:



Hi, thanks for your replies^^

I found some encoders by clicking on a shop advertiding button on ebay .


Don't know why Rotary Encoders are hard to find and Gyros you can find anywhere ????