Sunday, July 24, 2011

July Fixes

So I started thinking about the endstop problem I was having while using the teacup firmware. I had wired my endstops to be normally open, when everyone else... on the planet... wired theirs to be normally closed.  a G28 would send whatever axis away from the minimum (the second part of homing), and when I closed the switch would stop because it looked like it finally got away from the minimum. Then I found this mechanical endstop schematic, and I wondered if maybe I had a tiny stroke last year... at 28. It seems I couldn't connect anything properly. 

And I found the speed issue I had yesterday was because MAXIMUM_FEEDRATE_E was set too low. Here is the now more... sensible diff.

Saturday, July 23, 2011

July 2011 Updates

       I found that the firmware I had been using would require too much work going forward and I started a switch to using the Teacup Firmware.  Here's a diff of the changes I made.  I mostly made some small changes to my hardware to match closer to the firmware standard.  It seems to work great, except for a few middling things I still have to figure out, speeds are off.  This also means that I can switch to other host software and I'm presently using the 0025 release of ReplicatorgReprap Host worked well enough, but I can debug a lot easier with Replicatorg and it has included Skeinforge for a while.  Skeinforge is the one thing I don't think I'm changing anytime soon.  I also found in the course of this updating that I'm terrible at electronic design... well I suppose I'm better than I was... because I found the problems. I was terrible, I'm somewhat better now.  I had wired my heated bed in silly way, sharing the 5v- with the 12v+, the resistors were wired in two parallel sets of series resistors, which is now completely in series 12+ and 12-.  I also had added a 5v line to each of the minimum limit sensors... unnecessary with physical switches.  I cleaned up some wiring and fixed the pwm board to add some diodes and change out a transistor.

       Earlier in the month I bought a groove mount thermal barrier from makergear.com, which I found is based just about 30 minutes north of here... cool shit, on both points. I don't see any reason why to use any other design for a thermal barrier for a while. It's a great design and having tried it with PLA and ABS.  It works, and works well... I'm buying 10 once I have some money.