4xidraw

4xidDraw

What

The 4xiDraw is a diy xy plotter made from off the shelf materials and 3d printed parts. Perhaps it is a drawing machine more than a plotter. It can use regular felt-tip pens, ball pens or fountain pens as pen orientation is variable. It is a new version of an XY plotter using a single belt and two stepper motors in a configuration called h-bot. 4xiDaw instructables page

The plotter is Arduino based, and uses a special flavour of GRBL software created by the robottini user. It enables GRBL to handle a servo on digital pin 11 using commands M3 and M5. This way it can raise and lower the pen on the paper. Find the GRBL version here: servo GRBL and info how to flash GRBL to and Arduino here
About Grbl
Grbl is a free, open source, high performance software for controlling the motion of machines that move, that make things, or that make things move, and will run on a straight Arduino.

How

Inkscape

First, we will use Inkscape to send images to plot. Inkscape is a free and open source vector graphics editor.
Download here

We will have to install an additional extension for Inkscape in order to send our images to the 4xidraw.

Download it here

Find out how to install inkscape extensions here

Universal Gcode Sender

Universal Gcode sender is a full featured gcode platform used for interfacing with advanced CNC controllers like GRBL and TinyG. Universal Gcode Sender is a self-contained Java application which includes all external dependencies, that means if you have the Java Runtime Environment setup UGS provides the rest.

gcode

From Wikipedia on G-Code: G-code (also RS-274), which has many variants, is the common name for the most widely used numerical control (NC) programming language. It is used mainly in computer-aided manufacturing to control automated machine tools. G-code is sometimes called G programming language, not to be confused with LabVIEW's G programming language. G-code is a language in which people tell computerized machine tools how to make something. The "how" is defined by instructions on where to move, how fast to move, and what path to move. The most common situation is that, within a machine tool, a cutting tool is moved according to these instructions through a toolpath and cuts away material to leave only the finished workpiece. The same concept also extends to noncutting tools such as forming or burnishing tools, photoplotting, additive methods such as 3D printing, and measuring instruments.

File extentions: .gcode, .mpt, .mpf, .nc and several others

Simply put, G-Code is the language that tells the machine what to do, which movements to make, when to deposit material, when to stop etc. etc.. For example, a simple G-Code line that tells the machine to move to position X:10mm, Y:10mm could be:

G1 X10 Y10 

Here the code G1 is the code for move to. To draw a square with the 3D printer would require four such movements. Assuming we start from location X0 Y0 Z0 and want to draw a square of 10 by 10 mm:

G1 X0 Y10 
G1 X10 Y10
G1 X10 Y0 
G1 X0 Y0 

For a list of G-Code commands an Ultimaker 3D printer understands (or a printer running Marlin) see: https://github.com/ErikZalm/Marlin/blob/Stable/Marlin/Marlin_main.cpp Scrolling down will reveal the G-Code list.

An easy way to manually control your printer and send G-Codes by hand is Pronterface/Printrun: http://www.pronterface.com

Another square

M03 (pen up)

G21 (All units in mm)

G00 X20 Y30 
M05 (pen down)
G01 X200 Y30 F2000
G01 X200 Y200 F2000
G01 X30 Y200 F2000
G01 X30 Y30 F2000

M03 (pen up)
G00 X0 Y0 (going to 0 on both axes)

G commands

G0/G1
Linear move.  Moves to coordinates XY (or Z) and extrudes E material at a speed of F
example: 
G1 X500 Y500 E50 F3600 


G2 
Clockwise arc move. Moves in an arc to coordinates XY, pivoting around relative coordinates IJ, extrudes E material between the two points at speed F 
example:
G3 X90 Y30 I13.5 J1 E20 F3600 


G3 
Counter-clockwise arc move.  Function is identical to G2 but reversed 
example: 
G3 X50 Y50 J30 E10.34 F4800


G4 
Dwell for duration P (Milliseconds) or S (seconds) 
example:
G4 S2 


G20 
Change coordinate mode to Inch 


G21 
Change coordinate mode to millimeter (default) 


G28 
Home axes.  G28 to home all, or specify XYZ 


G90 
Set moves to absolute positioning mode.  Moves will be in reference to machine zero 


G91 
Set moves to relative positioning mode.  Moves will be in reference to last toolhead position 


G92 
Override current tool position with given coordinates 
example:
G92 X50 Y50 Z1.34

F Feed Speed   Sets the feed rate, or rate of movement of the axes.


S Spindle speed

export Gcode via Inkscape

A short guide how to generate Gcode from your files in Inkscape

send Gcode via a python script

#!/usr/bin/env python
"""\
Simple g-code streaming script for grbl

Provided as an illustration of the basic communication interface
for grbl. When grbl has finished parsing the g-code block, it will
return an 'ok' or 'error' response. When the planner buffer is full,
grbl will not send a response until the planner buffer clears space.

G02/03 arcs are special exceptions, where they inject short line 
segments directly into the planner. So there may not be a response 
from grbl for the duration of the arc.

---------------------
The MIT License (MIT)

Copyright (c) 2012 Sungeun K. Jeon

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
---------------------
"""

import serial
import time

# Open grbl serial port
s = serial.Serial('/dev/ttyACM3',115200)

# Open g-code file
f = open('simple.g','r');

# Wake up grbl
s.write("\r\n\r\n")
time.sleep(2)   # Wait for grbl to initialize 
s.flushInput()  # Flush startup text in serial input

# Stream g-code to grbl
for line in f:
    l = line.strip() # Strip all EOL characters for consistency
    print 'Sending: ' + l,
    s.write(l + '\n') # Send g-code block to grbl
    grbl_out = s.readline() # Wait for grbl response with carriage return
    print ' : ' + grbl_out.strip() # prints the ok response from grbl

# Wait here until grbl is finished to close serial port and file.
raw_input("  Press <Enter> to exit and disable grbl.") 

# Close file and serial port
f.close()
s.close()