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Yeah! I just got the stepper and gearing for Y-axis to work. The current setup seems to achieve even better precision than the X-axis I tested previously – we’re talking something like 900dpi – which is an estimate at this time. I use Mitsumi M42SP-7 stepper from Canon BJ200EX printer running on 12V and the gearing is customized from the aforementioned printer and Canon D1250U2 flatbed scanner. No pictures this time though :P

Next on my list is to make the X-Y table so I can start testing and calibrating it. When I get that done, I’ll move on to the Z-axis. It is going to be the most tricky part, and I suspect it’s not going to be as precise as the other two. I’ll probably need to build the whole mechanics from scratch if I cannot find suitable drive belt for it.

On other stuff, I finally received some PWM ICs from Texas Instruments for my moodlight project. The chips include 24-channel 12bit PWM, which is ideal for the RGB setup. Too bad it’s in HTSSOP32 package so I need to make a small PCB in order to mount it on my prototyping board, lets hope I can find time to make that at work :)

Shit, I just found a bug in my GCode interpreter, the Y-axis drive is not working as intented through ReplicatorG. Oh well, it seems to be only a misconfiguration on my behalf. Off to fix that.

I did a quick trip to visit some relatives and at the same time picked up two old printers and one scanner. After disassembling them I found out that there’s some nice steppers for my plotter project, though some redesigning of the driver circuitry is needed since the stepper motors from the printers run on 24 volts and my original circuitry is built for 5 volts. There’s also another little thing – two of the motors are bipolar and my circuit is for unipolar motors, but luckily I now have 3 unipolar and 3 bipolar motors so for three axis I should have enough unipolars to do the drive mechanics. There’s also a possibility that I get another scanner next week and get another unipolar stepper motor from it – fingers crossed that it’s exactly the same as the first scanner I disassembled – at least the model number is same :)

Here’s some pictures of the loot.

Disassembled printers

On this picture, there’s two disassembled printers. I was a bit amazed since the printers, a Canon BJ-200EX and Canon BJC-2000 contained almost exactly same circuitry and drive mechanics even though the BJC-2000 is significantly newer product. The main differences were in the driver ICs used to power the stepper motors, BJC-2000  uses only a single chip to drive the bipolar stepper when BJ-200EX uses a combination of two chips. Loot: 2 Mitsumi bipolar 24V stepper motors, 2 Mitsumi unipolar 24V stepper motors, lots of gears and pulleys and some nice motor driver ICs.

Planning..

Checking if the drive mechanics from Canon BJC-2000 would fit on the old Mustek 1200CP flatbed scanner’s mechanics. The idea seems to work but I need more precise drive for the belt in order to get enough precision for the plotter. The goal is around 600 DPI for extra precision, though less will also do at this point. Actually I think that even 100 DPI would be enough for relatively simple shapes.