Printrun issues with USB connection and OS X

I spent quite some time trying to get Printrun to connect my RAMPS board. The fix was to set the baud rate lower with #define BAUDRATE 115200 both in Marlin Configuration.h and in Pronterface user interface.

The screenshot below shows necessary details:

But the while I was testing some models there were long pauses in the print. Those were long enough to clog the hot end as the heating was on but no filament was pushed through. After couple attempts I started to use SD-card reader on the LCD display unit.

Wiring done

Wiring was pretty easy to get done but it looks pretty messy. I have to wrap wires somehow together and think some clever routings. It is important to make sure cables have enough length for the whole movement of the axis. I almost snapped the end stop of from X-axis because I didn't remember it moving higher as the Z increases.

While I was testing the cabling I could not get extruder stepper working. I thought I had burnt driver but in the end it was the 'cold extrusion prevention' feature of the firmware. Simple fix this time. Also, some of the axis were moving to wrong direction but I fixed that in the firmware configuration.

Marlin firmware

In order to get Arduino Mega clone and RAMPS board to function properly I need to install a firmware to Arduino. There are several choices but I decided to start with Marlin. It seems to be actively maintained and has good support.

I downloaded release version 1.0.2 and started to work with the configuration file. I did not modify too many settings at this point. I only selected correct motherboard settings and enabled LCD support. After uploading the firmware I disconnected Arduino and pressed the RAMPS board on it. I also hooked up the LCD screen cables and powered everything up. The LCD lit up and the menu was operational so I guess it works ok.