My first drawing is complete

In an act of utter self-glorification, I made the first thing to be written by the 2D repstrap be the first letter of my name (also, it was only orthogonal lines). After some as just unexplained problems with the Y stage refusing to start, and a slightly wobbly fastening of the Sharpie, it indeed made a letter L (in Blocky Outline 83 point or so). I have now successfully programmed and output something with my RepStrap! Woohoo!

The next thing should be a fractal. Just because.

It moves! It lives!

Having mostly dealt with the problems from last post (Flimsy wiring? Get the right jacks. Overheating driver? attach driver directly to frame. Loose coupling? Tie down coupling with hose tightener (which required dremelling a hole for the screw to rotate through), I have been able to make both X and Y stages move! The whole setup also looks much tidier now.

The stages can move for a seemingly arbitrarily long time, but they still overheat if standing still for about 30 seconds. Have to find a solution for that. I don't know if thermal paste will change much when I've already bolted them tightly together.

Major problem: Both stages have a tendency to switch between running smoothly and getting stuck, depending on exactly how the rod is aligned. I'm guessing the guiding bolt is a little loose, and can change between perfectly aligned with the rod and not quite perfectly aligned.

After cutting off superfluous edges and cutting a notch on the Y stage for the tube tightener screws, I have about 11x16 cm of writeable area. Not a lot, but enough for tests and for a RepRap, should I go that way (requires a plastic extruder, though. First some 2D tests!)

Softwarily, I have refactored the little test program to where I have two functions: move(dir, axis, len) and pauseSeconds(seconds). The move() functions is almost calibrated to move in cm.

For playing around, I am tempted to hook up three three-way switches so each axis can be controlled independently. Or maybe get a mini joystick controller:)

It's alive!

My mad genius neurons are all a-twitter with excitement! My creation moves! It's alive! (For very small values of alive.)

I've hooked up the new power supply and both of the mounted motors to the stepper drivers, and the Arduino to a solar powered (!) USB power supply. Pins 4 and 5 drive one stepper and 6 and 7 drive another, with the standard test program that merely moves back and forth. And the Y stage moves! Happily, happily back and forth. The X stage, not so lucky, the tubing is not tight enough to move the weight that's on there, so I'm currently glueing it on. Should be ready to run tomorrow evening.

Issue 1: The wiring is flimsy at best. I need some jacks that fit the Arduino, and maybe a little board that I can mount the various things on so they're less random. Just mounting the drivers next to the motors would help.

Issue 2: After 10-30 seconds of power, the stepper drivers start to stutter audibly, whether actually moving anything or not. I suspect the power transistor is getting too hot and starting to flake out. It certainly gets hot. I thought my heat sinks would be enough, but maybe not. Must go to Aarhus Radio Lager and get better.

Issue 3: As I mentioned, the X stage coupling is not tight enough. Not sure what the best way to make it be tight and stay tight is. Maybe just tie a lot of string really tightly. Or tie some string that will shrink when wet.

Working power supply

Briefly tested the new power supply, and it works with a big resistor on 5V. Lights up the stepper motor driver bicolor led somewhat prettily. Tomorrow: Rewire the stepper motors according to some hint I got from another Sanyo user.

New power supply coming up

Thanks to my brother's people-wrangling abilities (surprisingly good for someone who's pretty Aspy), I have a new old power supply on the way. The two big ones didn't work out. One of them spins up, but doesn't deliver power no matter what I try to put on for load and shorts, the other one doesn't even make a sound.

I got a new power supply to replace the one that got broken by jitter (two, actually, but one of them doesn't seem to work). This one is from an IBM PC 330 server that I got for $5 from the local second-hand store. I can tell that it works, as it actually spins up a little even when no power is drawn.  This is the label:

However, it's a big and special power supply with connectors I haven't seen described in the usual literature. 

This connector P3 looks a bit like the two old AT style connectors rolled into one, but the wiring color is all wrong.
Front look of P3.

There are also two huge connectors P1 and P2 (not connection to bananas) that I have never seen before. Serious mofos with thick wires (standard harddisk connector shown for comparison - look at the size of those things!). Probably can't use these easily, but I feel certain that it can give the output I need. It also has not 4, not 6, but 8 standard harddisk connectors plus assorted small bits.

Here is a better view of the wires for the non-standard 10-pin connector. The white would be -5V, the gray a power on indicator, the black ground, the yellow 12V, the blue -12V, but I don't know what the brown would be, and the green is a power on input. Maybe the brown is 3.3V sense (only brown I've seen mentioned), but that makes no sense with no 3.3V output.

Update: Tried with shorting the green to black, and with a 7W 1 Ohm resistor between a 5V and ground. The power supply hums merrily, but there is nary a blink of power output. Strange.

X and Y mostly done

Got the last bolts today, so the X and Y stages are pretty much done. The Y rod has been lined up, and the motor attached. When rotating the motor, the driver LEDs light up. Still need to get the endstops to work, and to get a working power supply - how hard can it be? The new server has one that works, so either I can get power out of that, or I have three supplies I need to do something special to.