I wanted to add an encoder to my GM3 drive motor, but I've previously blown my three spare opto-switches.
Asking around at work, I found an old ball mouse with a broken USB plug, and got permission to take it home from sysadmin.
Logic dictated that running off USB (5v) it might contain some opto-switches that I could recycle. Taking it apart, a quick inspection revealed two components either side of a slotted wheel that looked right:
I desoldered them, ripped out the broken IR sensor from the x-max endstop board, and just soldered them in.
Hooking it up to the arduino, it works perfectly!
Other extruder bits:
I found some thin-walled alumininum an brass tube in a Model shop in Westbury. It's imperial (5/32) but the internal diameter is exactly right for my 3.1mm filament.
I think it might work well to make vik's no-lathe/ariel extruder, or to make a Nophead-style thin-walled extruder. I've got a large heatsink from a core2 CPU to go with it.
I've been looking for a block of metal to make nophead's resistor heater for a little while - it's not something you can buy in B&Q, and I don't happen to have aluminium bar stock in my garage. :-)
In the middle of Bath, down by Sainsburys, I walked past a little tool shop that was selling scrap metal outside. I went in and asked, and...
Hey presto, the chap disappeared out the back and came back with a 10mmx30mm bar - and cut me off a couple of 30mm lengths from it. The best bit : cost 25p. So, a shout-out to the guys at Avery Knight and Bowlers, Bath - thanks guys. They've been consistently helpful and the shop is full of tools and other useful bits. I also grabbed some m6 coupling nuts - might be useful to attach nozzles - and a 7.5mm drill, which is the right size for my resistors.
I've thrown a few quid away on some tattoo tips from a dodgy overseas company (like these ones). I wanted to have a look to see if they would be useful to turn into nozzles. When (if) they arrive, I'll post some measurements and photos.
Edit: half-hour after posting this, I noticed a big split in the mains cord insulation for my wife's hairdryer. 'It's not safe, we'll have to you get a new one' - of course, nothing to do with the fact it's full of nichrome wire....