Andy, I have made one before with just a piece of photo negative film. Speak to your trusted offset printer and ask if he still uses graphic film and who can print it for you from a pdf or similar. To assemble figure out some way to register it on the small metal disk you machine on the shaft end and glue.
After all my rubbish HP inkjet worked for years with a linear strip of the same as a linear scale. Cheers, j. On Fri, May 25, 2012 at 2:09 PM, andy pugh <bodge...@gmail.com> wrote: > I have built a motor. > Internal space is quite tight, so I am using the Avago AEDR8340K > encoder detector > http://uk.rs-online.com/web/p/rotary-encoders/7160604P/ > (Also available from Mouser etc). This is a 3mm x 5mm two-channel > quadrature detector. TTL output wires direct to Mesa / Parport / Pico. > I initially tried to make my own encoder disc by etch-resisting (with > a pen) some polished aluminium then etching with FeCl > http://youtu.be/c1zCG-uPaoM > This almost worked, but there was a problem with missed/multiple > counts. The AEDR application notes make it clear that it really can't > be expected to work right at anyhting other than native resolution. In > the case of the "K" variant that is 75lpi, which means 0.15mm (0.006") > slot width. i got a quote for Photochemical etching from Photofab > which was rather reasonable (£4 each) but with a £100 setup charge and > a 25 minimum quantity (s £200+ all in). > I then found that within half a mile of my house is a company who > specialise in laser cutting solder stencils for PCB assembly. They > have a machine with a 25um beam width optimised for cutting stainless > sheet: > www.sparkslaser.com > They are doing me 2 different parts for £50 (and have already given me > one fully-finished part as a "sample", which tested with 100% success > this lunchtime. > > I will get pictures later. > > This seems like quite an easy way to make a spindle encoder, for > example, where off-the-shelf encoders tend to have too small a bore. I > imagine that if Basildon has a stencil-making business, then they must > be numerous. > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
