GUS Simpson electronics and calibration
Introduction
GUS Simpson has no firmware yet. In order to get it working a gcode preprocessor is used, while GUS being configured as a dummy cartesian printer. Be aware that sending a cartesian gcode on the GUS may harm the device, and never would give any results. While you can use pretty much any firmware capable of running cartesian printer, a [Repetier] is suggested.
Configuring the firmware
Start by configuring the firmware. Most firmwares comes with default settings for X, Y and Z axis. You will need to configure the firmware so the X, Y and Z motors have the same settings. Do not configure steps/mm just yet, give it placeholder value, you will need to change it later. Here is an example [Repetier] configuration.
Calibrating steps/mm
It is very important you do this right. You will need a calipers capable of measuring at least 300mm.
- While having placeholder values for steps/mm, detach the arm you about to calibrate from the hub.
- Home all the axis.
- Make sure eccentrics are fixed solid.
- Home all the axis again.
- Measure bolt to bolt distance on the ends of the arm with the calipers and write it down.
- Close the arms as much as possible and write down software coordinates of the arms. Make sure there were no skipped steps.
- Measure bolt to bolt distance again, write down the value.
- Calculate new steps/mm value: A * S/(Max- Min), where A is the old steps/mm value, S is software coordinate and Max and Min are bolt to bolt distances.
- Place new values in the firmware.
- Repeat, until you have the same value after calculation.
Calibrating segmentize
When you have steps/mm figured out you should add some points to segmentize. Open the script in text editor and find the POINTS array. You should fill it with at least 6 points where the extruder barely touches the bed. You should be able to slide a piece of paper between the nozzle and the bed with no dragging. Once done the segmentize should be ready for printing.
