When you say that there are step and dir signals available on the motherboard, which pins are used? The only places in the motherboard firmware where those pins are referenced (that I can find, anyway) refer to the i2c pins 16 & 17 (SCL & SDA). But I can't just wire those to the pololu step and dir pins; they have 3.6K of resistance between them for i2c. I found this page where a poloby eustace - General Mendel Topics
I'll have to wait until I get home tonight to answer that, but it's the version you get when you download it from the main link in the Build Mendel pages. The only change I made to it so far is to add the two variable declarations (temptable and bedtemptable) that are being discussed in the firmware thread. This works, to a point. The led is flashing, the console is showing messages (includingby eustace - RepRap Host
Tried it - at 19200 - and it worked. One hurdle down...by eustace - RepRap Host
Does the difference in baud rate explain the host software failing to run? After all, if I leave the cable disconnected, so that there is no COM5 on the machine at all, the program will finish loading, and all three windows will be open (command line, Reprap console, and stage view).by eustace - RepRap Host
Found it, I think. HOST_BAUD is being set to 19200. Should I bump it up, or turn it down in the host? Right above where it gets set, there's a remark that says default is 57600. Right below that, all configurations get set to 19200 except MENDEL_MEGA_DEFAULTS. I guess default doesn't mean what it used toby eustace - RepRap Host
The host software is set to 57600, but I can't find where the baudrate is set in the firmware.by eustace - RepRap Host
I'm trying to test my motherboard, but I can't seem to run the host software if my FTDI cable is plugged in. The cable appears as COM5, and I changed preferences to COM5, and now when I run the host software it never gets beyond the command line window. If I run it with the debug comm option off, it only gets as far as "Java lib Version = RXTX-2.1-7" then nothing. If I turn debug comm on, I geby eustace - RepRap Host
But if I run the step and dir wires from the mobo to my pololu carrier board, and then attach the microstepping control pins (ms1 thru ms3) to gpio pins on my extruder control sanguino, I might be making a ground loop or something - I'm not an electrical engineer, and that kind of wiring makes me nervous. And we were just discussing firmware issues; wouldn't I have to make firmware changes for tby eustace - General Mendel Topics
I'm planning on using the Sanguino with a bit of proto board to hold the extra components and to allow me to mount it normally. I'll drive the heater thru a mosfet and use a pololu board to drive the stepper (with all the io pins a Sanguino has, I can wire up the pololu board to allow microstepping, even if I don't use it at first). I guess my motherboard is Gen3; it's a reprap version 1.2 board.by eustace - General Mendel Topics
One approach is to pick one of the two - studding or nut - to be sacrificed to the other. That is, use hard steel for the studding, and brass for the nut, then replace nuts as they wear out, or stainless nuts and brass studding and replace the studding. Do not use stainless for both - even with careful and frequent greasing they will eventually gall and you'll have to replace both. Zinc platingby eustace - General Mendel Topics
I would like to use a Sanguino that I already have instead of an Extruder Controller board that I would have to buy. To get the code to compile, I have to rem out these lines: //#ifndef __AVR_ATmega168__ //#error Oops! Make sure you have 'Arduino Diecimila' selected from the boards menu. //#endif ...then it will compile. But I wonder if I'm going to have trouble with the timer changes the codby eustace - General Mendel Topics
Thanks for the advice, nophead. I've already ordered PLA, but now I'll consider getting some ABS for troubleshooting.by eustace - Reprappers
Real circulating ball screw assemblies are expensive - VERY expensive. Hundreds of dollars apiece. I'm currently designing a mendel version with a larger print area (12in x 12in x 10in high), using Acme nuts and screws instead of belts. Much less expensive. Still slow, though, compared to the belt drive x and y axes. My current (experimental) x-axis design requires eight times as many turns oby eustace - Extruded Aluminum Frames
I'm unable to buy an extruder controller from Makerbot (out of stock) so I'm rolling my own. I'm using a boarduino, an IRF510A to power the heater, and a nifty breakout board for the Allegro 4983 stepper driver (does microstepping to 16X!) as my protoboard version, prior to having a custom board made. While I wait for my SN75176 to arrive, I breadboarded the rest of my circuit and opened the fby eustace - Controllers
For a while, there, neither had the soic part. I'm ordering a dip part for the protoboard extruder controller. My confusion over the pinout was just self-inflicted - I needed to take a closer look at the schematic. But the breakout board SP3485 came in handy. It really is a drop-in replacement if you have a 5V circuit (or so I'm told) so I removed it from the breakout board and put it on my motby eustace - Reprappers
The continued unavailability of the SN75176 chip is keeping me from completing my electonics, so I started looking for a replacement part. I found a Sparkfun SP3485 breakout board, and I thought I might be able to use it to provide communications for my protoboard Extruder Controller, but then I noticed that the chip is wired differently, with /RE tied to DE. When I compared this to the Motherbby eustace - Reprappers