The Tao of Walking Ridge

I tried a brand new 3rd USB cable just to be sure, and some different baud rates. But I could not get the board to hook up to the PC. In Repsnapper I turned on a heater and the command was never obeyed, just repeatedly sent.

While frustrating, the good thing about these kits are that they are like hot rods. If you can’t find an exact replacement part, just modify it to fit something different. On eBay I found a Makerbot V1.2 board used for $50. It will require different wiring and other bits, but will be one option. I’m still searching for another monolithic board to try. There are also older Mendel set ups and putting together an Arduino board from scratch. But at this point, it looks like some new bits will be the way to move the project forward.

Another possibility is a different 3D printer (the Up! compact printer looks interesting) and use the bits of the Huxley project for a “RepStrap” project. A CNC router for example. The stepper motors can be adapted for that, and the STL to Gcode conversion programs are incredible front ends. One possible idea is writing a Python (NOT Java!) script to allow an old pc like my Thinkpad 600 to directly control actuators through a parallel port.

So, the project is holding steady at 28 hours awaiting parts.

Progress is extremely slow.

The good news: I’ve gotten Repsnapper, RepRapHost, and Arduino software to run. I got Repsnapper running on Windows XP and Ubuntu 10.04. Repsnapper was helpful in that it clearly indicates that the printer is not connected. In Linux, it clearly finds the correct port, but does not stay connected.

The bad news. Nothing talks to the board. Nothing connects. It appears that the correct 3 axis stepper motors are powered. Therefore, it appears that there is firmware on board. If the baud rate is not matched, then it will not communicate, but I can only assume the default baud rate is on the board. So, the next step seems to be to reflash the board……..but first you must get “sketches” in Arduino (programs to the non-creative) to compile.
Read the rest of this entry »

Well, the project is stalled. After four hours, I was able to wire the motors to the controller board. The connector on the power supply was not correct. It was a PS2 style connector and the power supply was a pin jack. I was unable to figure out for sure which polarity the connector on the board was. I tried to download the schematics but they would not open. Taking a chance that the positive would be the pin as labeled on the power supply I cut off the connector and soldered on a pin I found from a Futaba charger. It seemed to be right. I was able to adjust the trim pots for the motors.

But, I was not able to get the PC to control the motors. I hooked up the USB cable, my Linux machine found it (I found instructions for checking this through the Bash terminal). I got the RepRap software to run and the RepSnapper software to run on Windows. But I could not get the motors to move when I adjusted the software. So, after another four hours, I am stumped. It is a bit baffling to figure out which card it is, how to upload the firmware (which is already supposed to be leaded) and how to debug the thing. So many instructions are on similar boards, but not the same and often the instructions are a set of pictures. Total time so far, about 18 hours.

Update: After taking a break I began reading. The instructions said if the computer doesn’t talk to the board try reflashing. That sounds very easy. But………..the instructions for reflashing are elsewhere, and usually for other boards. Finally, I figured out that (I think) what is needed is some compiled Gcode interpreter. But that requires a C compiler to work right, and it seems that the Ubuntu compiler doesn’t like the avg- something compiler. One page suggested that this needed to be upgraded, and there is a page full of instructions on how to upgrade this piece of the compiler to hopefully get the scripts to compile (no guarantee as the board uses Sanguino) which would then allow the Arguino software to upload the firmware to the board. If that is the issue.

It might be worth trying it in Windows now to see if it compiles there. There are fragments of instructions regarding the electronics, but it is difficult to find debugging for the Gen3 Sanguino Monolithic board. I did find notes on the Arduino boards that they used positive tip power connectors. So it appears that part is right. I did find a fix for one of the compile errors, but the suggested fix is adding a line to a file that I cannot find. At this point I can’t get the computer to talk to the board and move the motors. Total time now about 22 hours.

Day five made pretty quick progress. I worked slowly over 4 hours to assemble the bits and align the rods to be square. It was helpful to put the smooth rods in the bearing assemblies as it was assembled to prevent binding. The next step is to start installing the motors and electronics. Total time so far is about 14 hours.

In three more hours I was able to finish the X axis assembly and start on the Z axis. There are several pressed in nuts in these bits, and the suggestion was to heat them to aid assembly. I opted to use an inexpensive arbor press and found that to be a very effective tool. No parts cracked, though some required a little tapping to get them totally in place. As the parts are used, there are fewer remaining and it becomes a little easier to know exactly which part is needed next. I also started to get the hang of how the bearings are attached, which sped things along a bit. I did spend a half hour on the X axis after assembly getting the carriage to slide smoothly. Total time so far is about 10 hours.

These couple of assemblies took about 3 hours to sort out. I worked slowly to get the right parts and orientations and think I got it right. However, so far parts are just finger tight so time will tell if I’ve got everything right. Though I read a note suggesting the bushing be split to be more stable, I opted to leave it one piece and and try it. I was concerned that a bad cut would cause as much drag and trouble as working with the shorter bushing. Total time so far is about 7 hours.

I am very glad I opted for the kit from clintoncwandrus on eBay. There are many parts, and I enjoy the challenge of assembly more than the challenge of looking for sources for all the parts.

I only got an hour to work on the project today, but an hour at a time makes notable progress. I was able to assemble the frame. At this point all attachments are finger tight. This allows for adjustment as the parts go together. There is little chance the parts won’t fit, but as some point later some adjustments will be needed to get everything properly aligned. Total time so far is about 4 hours.