Tested on RaspberryPi Model B+ but should work for any Raspberry Pi.

This Ruby gem allows you to control different kinds of stepper motors. You can use this gem to run both Bipolar and Unipolar motors with either L293D or ULN2800 Integrated Controllers.

Make sure that you have WiringPi installed first

gem install wiringpi

If you are using GPIO Pins from a A+/B+, you may need to update your WiringPi libraries. You can pull from my repo https://github.com/kobaltz/WiringPi-Ruby

I did not write any of the WiringPi-Ruby platform. I simply pulled the latest C libraries and recompiled the gem.

gem install rotor

This gem has been built for my personal project. I do not and cannot know if this will work with your setup. However, put in an issue if you're having troubles with this gem and I will try to help you as best as I can.

I am using two stepper motors (NEMA17 Bipolar 20Ncm 12V) and two L293D motor drivers. This gem has also been tested with a small 5V Unipolar Stepper Motor and 12V Unipolar Stepper Motor.

My Steps Per MM is based on a 200 step per revolution motor and a threaded rod with 20 threads per inch. This means that I will have to step 4000 times to move the coupler one inch.

MAKE SURE THAT YOU HAVE CONFIGURED THE Rotor::Stepper WITH THE CORRECT GPIO PIN NUMBERS. CHECK AND DOUBLE CHECK THESE BEFORE RUNNING YOUR CODE. This has been tested with both Bipolar and Unipolar Stepper Motors

stepper = Rotor::Stepper.new(coil_A_1_pin, coil_A_2_pin, coil_B_1_pin, coil_B_2_pin, enable_pin=nil, homing_switch, homing_normally, steps_per_mm)
stepper.forward(delay=5,steps=100) # stepper.forward(5,100)
stepper.backwards(delay=5,steps=100)# stepper.backwards(5,100)
stepper.set_home(direction) #:forward or :backwards
stepper.at_home?
stepper.at_safe_area? # opposite of at_home?

After running your GCode, you may want to consider to power down the motor by sending a LOW to each step.

stepper.power_down

You can use a servo to control the marker (or leave blank if you're using a Z Axis Stepper) This will be built out so that the strength control of the servo (for laser power) can be adjusted and inputs sent in. However, for development purposes, I recommend not playing with lasers, but rather get the machine and code working properly first.

servo = Rotor::Servo.new(pin=18)# Rotor::Servo.new(18)
servo.rotate(direction) # :up or :down

The plot points are streamed to output.txt file on your computer.

You can test the outputs of your GCODE and the XY plots it creates by Rotor.

File.open("output.txt", 'wb') { |file| file.write("x,y,xm,ym\n") }
gcode = Rotor::Gcode.new(nil,nil,nil,1,nil)
gcode.open('output.nc')
gcode.simulate(accuracy=8,speed=1)

When using the simulate option on the Gcode class, you can now enter additional parameters which will increase accuracy as well as speed. The accuracy parameter will be used in the logic of determining how many steps in the arc will occur. The Max of the distance calculation and accuracy variable will be the number of steps on a given arc. The speed parameter is in ms and will be the delay between steps.

The goal of this gem is to make controlling your robotics easier than other solutions.

Added Homing Switch options where you can add the GPIO of the switch and indicate if it is normally open or normally closed. I have my homing switches on each axis configured in parallel since I know the direction that the panel is moving in and therefore know which side it has hit. This was to reduce the number of GPIO pins required.

stepper_x = Rotor::Stepper.new(23,12,17,24,nil,13,0,157.48)
stepper_y = Rotor::Stepper.new(25, 4,21,22,nil,19,0,157.48)

You can send the stepper motor to the outter edges of the board. You will want to play with the :backwards and :forward options to make sure that they’re moving in the correct direction for your stepper motor.

stepper_x = Rotor::Stepper.new(23,12,17,24,nil,13,LOW,157.48)
stepper_y = Rotor::Stepper.new(25, 4,21,22,nil,19,LOW,157.48)

stepper_x.set_home(:backwards)
stepper_y.set_home(:forward)

loop do
  puts "Enter steps forward::"
  text = gets.chomp
  
  threads = []
  threads << Thread.new { stepper_x.forward(5,text.to_i) }
  threads << Thread.new { stepper_y.forward(5,text.to_i) }
  threads.each { |thr| thr.join }

  puts "Enter steps backward::"
  text = gets.chomp

  stepper_x.backwards(5,text.to_i)
  stepper_y.backwards(5,text.to_i)
end

GCode can be simulated (this is my latest part of the project) where a file can be read in and the movements interpreted. Right now, G02 and G03 will work with I and J offsets. Radius is not currently supported.

Enter each stepper motor (or nil if you do not have that particular axis) along with the scale (multiplies all coordinates by this. Typically you will keep this at 1).

The last variable is the speed in which G0 will move. Typically, this move should be faster than your normal movement speed.

Rotor::Gcode.new(stepper_x=nil,stepper_y=nil,stepper_z=nil,scale=1,servo=nil,fast_move=1)

#gcode = Rotor::Gcode.new(stepper_x,stepper_y,stepper_z,1,servo,1)
gcode = Rotor::Gcode.new(nil,nil,nil,1,nil)
gcode.open('sample.nc')
gcode.simulate(accuracy=8,speed=1)

By passing nil into each stepper motor and servo, you can simulate the GCode execution.

By default, if you run the first motor and then the second motor commands, the first command will execute first and the second one will execute afterwards. This may not always be the desired result as your plot/laser/mill may get ruined by having nonsynchronous movements.

Since Ruby by default will not asynchronously execute commands, you can combine the X/Y/Z movements into their own threads.

threads = []
threads << Thread.new { stepper_x.forward(5,text.to_i) }
threads << Thread.new { stepper_y.forward(5,text.to_i) }
threads.each { |thr| thr.join }

Here is the real world sample code that I am using to plot

require 'rotor'
begin
  stepper_x = Rotor::Stepper.new(23,12,17,24,nil,13 ,0,157.48)
  stepper_y = Rotor::Stepper.new(25, 4,21,22,nil,19 ,0,157.48)
  stepper_z = Rotor::Stepper.new(16,20, 6,26,nil,nil,0,157.48)
  puts "Moving to home and soft origin"
  stepper_z.forward(1,10) 
  stepper_x.set_home(:forward)
  stepper_y.set_home(:forward)
  stepper_x.backwards(2,120)
  stepper_y.backwards(2,70)
  stepper_z.backwards(1,10)
  puts "Running Code"

  gcode = Rotor::Gcode.new(stepper_x,stepper_y,stepper_z,1,nil,1.5)
  gcode.open('output.nc')
  gcode.simulate(16,5)

ensure
  stepper_x.power_down
  stepper_y.power_down
  stepper_z.power_down
  [23,12,17,24,13,25,4,21,22,19,13,16,20,6,26].each do |pin|
   `echo #{pin} > /sys/class/gpio/unexport`
  end
end

Based on the code above, my origin (0,0) is one inch from the backwards X and one inch from the backwards Y

Before wasting more materials, I try to plot my points to a file and view them in Excel. Within the root of this repository, there is an Excel file, called Visual.xlsx, and you can import the output.txt into the first four columns. By doing so, you can see the plot points and the scatter of movements. Go to the data tab and click Refresh Data. Select the output.txt file that you generated and it will show the plot points. If you see some crazy stray points, you can put in a issue and I will look at it. Please include the GCode that you’re using that is causing problems.

Keep in mind that this keeps track of the coordinates, so you will see the entry and exit points as lines. This is expected behavior since I like to see where my marker is entering into an object.

File.open("output.txt", 'wb') { |file| file.write("x,y,xm,ym\n") }
gcode = Rotor::Gcode.new(nil,nil,nil,1,nil,1)
gcode.open('output.nc')
gcode.simulate

Copyright (c) 2015 kobaltz

MIT License

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.