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
