Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!spool.mu.edu!snorkelwacker.mit.edu!ai-lab!captain-crunch!klaus From: klaus@captain-crunch.ai.mit.edu (Klaus B. Biggers) Newsgroups: comp.robotics Subject: Re: What is the cheapest shaft encoder you know of? Message-ID: <16505@life.ai.mit.edu> Date: 14 Jun 91 21:10:57 GMT Article-I.D.: life.16505 References: <12518@qisoff.phx.mcd.mot.com> <966@agcsun.UUCP> Sender: news@ai.mit.edu Organization: MIT Artificial Intelligence Laboratory Lines: 18 In article <966@agcsun.UUCP> jackm@agcsun.UUCP (Jack Morrison) writes: >As I understand it, they have a magnet on the shaft, and a reed switch that >sees it go by each revolution. Then just count the transitions. ^^^^^ You will need to use some method to determine which direction to count, quadrature of some type, if your system is reversible, otherwise, when the system reverses, you will continue to count up when you should be counting down.... I hate it when that happens!! -klaus klaus@snowhite.ced.utah.edu _______________________________________________________________________________