Since you can get a 6" digital caliper from harbor freight for $18.99 with the computer interface shown in the article on piclist.com, I don't see any reason to make your own unless you need longer distances and have to buy a more expensive caliper. Resolution and accuracy are 1 mil. And yes, the price is correct, though it's on sale. I just found out that a new harbor freight store opened up a few miles from me in May, so I purchased one and verified that it does have the four contacts mentioned in the article. I'm tempted to buy 3 more since they are on sale, but I don't have to to build my own milling machine this year... But I *have* found a new tool store. :-) -Adam James Newton, Host wrote: >This is an interesting idea... > >...has anyone (other than me) actually tried it? Here is what I found: > >1. vibration in the cable just kills it. >2. laying the cable on a slide helps until it picks up crap and blocks the >sensor. >3. putting it in a tube requires that the tube be retractable > >I gave up at that point. > >I've never seen that plastic strip inside a printer, but usually see the >insides of laser printers; is that a dot matrix thing? > >--- >James Newton: PICList webmaster/Admin >mailto:jamesnewton@piclist.com 1-619-652-0593 phone >http://www.piclist.com/member/JMN-EFP-786 >PIC/PICList FAQ: http://www.piclist.com > > > > > >>-----Original Message----- >>From: pic microcontroller discussion list >>[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Martin Klingensmith >>Sent: 2004 Jul 20, Tue 18:45 >>To: PICLIST@MITVMA.MIT.EDU >>Subject: Re: (will be) Small CNC mill, controller and >>software for ~$500 >> >> >> > > > >>A linear DRO could be made with a tiny aircraft cable that >>got pulled in a loop by the carriage, and turned a rotary >>encoder placed stationary: >> >>------------------ >>| | >>|_______0__________________| >> ^-rotary encoder >> >>Printers use a plastic strip with clear/opaque stripes: >>| | | | | | >>read with an optical device that moves with the carriage. Two >>placed offset would give you double the resolution: >>| | | | | | >> | | | | | >> >> >> > > >-- >http://www.piclist.com hint: The list server can filter out subtopics >(like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics