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• Translating Word files to Braille

  Stephane • 13 hours ago • 0 comments

  Since we have tried MusicXML files a few days ago, i was wondering if there is a pandoc module available in python.

  Pandoc is a well known open source command line software to convert file format, you can use it to convert html to pdf or Markdown to html ...

  The main issue with word processor formats is that they can contain many features that are not really available in Braille. Different font and font size are not available in Braille, just because Braille characters is a normalized fixed size matrix of 6 or 8 dots depending of the Braille standard. 

  So to convert an Open Office .odt file or a word .doc you need a tool to extract  plain text from these files. This is were pandoc can be useful,  pandoc as a feature to extract plain text from many file format.

  After some internet search i found pypandoc, a python module to bridge pandoc with python software.

  So i start a little test with AccesBrailleRAP.  Just like we already done it with MusicXML, i add a bacend python function which ask a file to the user, convert the file to plain text with pandoc, and return the result to the javascript frontend.

  @eel.expose 
  def import_pandoc():
      js =""
      root = tk.Tk()
      
      fname = tkinter.filedialog.askopenfilename(title = "Select file",filetypes = (("all files","*.*"),))
      #print ("fname", fname)
      root.destroy()
      if fname != "":
           
          linel = int (app_options['nbcol'])-1
          
          data = pypandoc.convert_file(fname, "plain+simple_tables", extra_args=(), encoding='utf-8', outputfile=None)
          #print (data)
          js = json.dumps(data)
      
      return js

  and i just give it a try with a little openoffice test, just a text line with some format and a little table.

  Starting AccesBrailleRAP i test the new import button

  and select our open office .odt test file

  Not bad, we get all the text, and the table is conserved

  Converting that to Braille

  Gotcha, we have a proof of concept. we definitely need to build an installer to include all the needed software to work with AccessBrailleRAP (drivers, pandoc, ...) but this a promising feature allowing anybody to open a word processor file, convert it to Braille, and emboss it. You don't even need to know anything about Braille !

• Hacking AccessBrailleRAP with MuseScore

  Stephane • 05/28/2023 at 15:12 • 0 comments

  Since we started the BrailleRAP project a few years ago, we eared some peoples asking about Braille music score. 

  As we were focused on literacy transcription, we just put aside this feature, just noticing that Braille music score is just another standard in the Braille word.

  I'm not a musician, but sometime i love to make some music hack with bio sensor, midi and software synth on Raspberry PI. As hacking around with musical open source software, i've discovered MuseScore (https://musescore.org/). MuseScore is a wonderful and impressive open source tool to edit and display music score, as well as handling many music file format.

  Last night, looking for some python module for a customer, i just found music21 "a toolkit for computer-aided musicology" (http://web.mit.edu/music21/#) and this article by Young Choi about Braille and music21 (https://www.linkedin.com/pulse/convert-music-xml-braille-music21-young-choi/) with just a few lines of python to translate a musicxml file into Braille. Starting from Young Choi example, i just create a python venv and write a little script :

  import music21
  import sys
  
  print (sys.argv)
  c = music21.converter.parse (sys.argv[1])
  
  c.show ('braille')
  #c.show ('png')
  bu = music21.braille.translate.objectToBraille (c, maxLineLength=28, showHeading=True)
  
  data = bu.splitlines()
  for l in data:
      print ("{0} |{1}|".format(len(l), l))

  getting some musicxml around, i tried the script and get this

  and this in the console :

  33 |⠠⠉⠕⠍⠏⠕⠎⠑⠗⠒⠀⠠⠇⠥⠙⠺⠊⠛⠀⠧⠁⠝⠀⠠⠃⠑⠑⠞⠓⠕⠧⠑⠝|
  26 |⠠⠍⠕⠧⠑⠍⠑⠝⠞⠀⠠⠝⠁⠍⠑⠒⠀⠎⠉⠕⠗⠑⠲⠭⠍⠇|
  33 |⠠⠞⠊⠞⠇⠑⠒⠀⠠⠋⠈⠥⠗⠀⠠⠑⠇⠊⠎⠑⠀⠊⠝⠀⠠⠁⠀⠠⠍⠊⠝⠕⠗|
  27 |⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠼⠉⠦⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀|
  27 |⠀⠚⠀⠨⠜⠐⠀⠀⠀⠨⠯⠩⠑⠋⠐⠚⠡⠑⠙⠀⠐⠊⠍⠐⠙⠋⠊|
  27 |⠀⠀⠀⠸⠜⠄⠄⠍⠀⠍⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⠮⠸⠯⠮⠍⠭|
  23 |⠀⠉⠀⠨⠜⠐⠚⠍⠋⠩⠓⠚⠀⠀⠨⠙⠍⠐⠋⠨⠋⠩⠑|
  23 |⠀⠀⠀⠸⠜⠘⠯⠸⠯⠩⠷⠍⠭⠀⠘⠮⠸⠯⠮⠍⠭⠀⠀|
  23 |⠀⠑⠀⠨⠜⠨⠯⠩⠑⠋⠐⠚⠡⠑⠙⠀⠐⠊⠍⠐⠙⠋⠊|
  23 |⠀⠀⠀⠸⠜⠄⠄⠍⠀⠀⠀⠀⠀⠀⠀⠀⠘⠮⠸⠯⠮⠍⠭|
  22 |⠀⠛⠀⠨⠜⠐⠚⠍⠐⠑⠨⠙⠚⠀⠐⠪⠣⠅⠀⠀⠀⠀|
  ....

  a pretty well formatted unicode string with Braille music score ! wow !

  if you read about BrailleRAP, you know that AccesBrailleRAP, our Braille translation, software is based on eel python module. Eel allow you to embed html/javascript frontend and python backend on a packaged application for window.

  So i just started a new app for AccesBrailleRAB, calling it MusicBrailleRAP, add a page and button on the react.js frontend, and drop some python lines in the backend. With a little python function, we can open a file selection dialog, convert the file to Braille characters strings with music21 and return a result as JSON for the react frontend.

  @eel.expose 
  def get_file_dialog():
      root = Tk()
      fname = filedialog.askopenfilename(initialdir = "./",title = "Select file",filetypes = (("musicXML","*.mxl"),("all files","*.*")))
      print (fname)
      root.destroy()
      
      linel = int (app_options['nbcol'])-1
      
      c = None
  
      if zipfile.is_zipfile (fname):
          with zipfile.ZipFile(fname, mode='r') as archive:
              with archive.open ('score.xml') as score:
                  print ("trying to open a msz")
                  data = score.read()
                  c = music21.converter.parseData(data)
      else:        
          print ("trying to open a xml")
          c = music21.converter.parse (fname)
      
      bu = music21.braille.translate.objectToBraille (c, maxLineLength=linel, showHeading=True)
      
      data =str(bu)
      js = json.dumps(data)
      
      return js

  After a few hours of test and updates on the frontend and Braille paginator, i can now use MuseScore to open a music score.

  i use the export feature to export the score in MusicXml...

  Read more »

• Designing stronger motor support

  Stephane • 05/20/2023 at 13:13 • 0 comments

  In previous version of BrailleRAP the Y motor support whas this one :

  As the support work well, the 3d plastic deigned part sometime break at the layer jonction. Even if  the BrailleRAP was packed in foam, plane travel in cargo hold was hazardous for the support. We analyses the problem and thought that the weight of the motor with the big cantilever created by the design, could bend the support between the horizontal and vertical part.

  The goal was to kill the cantilever, adding some support on the motor back that we can secure with some screw on the frame. So we design a support like a cage, securing the motor in the cage with standard screw fixation of nema17 but now the motor do not have the ability to bend the support.

  As the support is not easy to print one a standard 3d printer, we cut it in 3 parts, allowing the user to build the support himself by securing the 3 parts with 2 screws.

  That's it the Y motor is now firmly attached to the frame with 4 screw and you still can adjust the motor position to tension the belt.

• Embossing Braille Dots

  Stephane • 05/18/2023 at 20:22 • 0 comments

  Basically BrailleRAP is a 2D device that move a tools (the Braille stylus and the corresponding anvil) over a sheet of material. BrailleRAP use a 3d printer control board, we use MKS boards as these boards are compatible with the marlin firmware (https://marlinfw.org/). 

  Marlin firmware enable the board to act as 3d printer, but more precisely, it can control several stepper motor in position / speed  / acceleration, read some sensors (endswitch, thermal resistor ...), and drive some tools like 3d printhead, heat bed but also CNC spindle motor etc.

  Another feature of Marlin, is the GCODE interpreter. GCODE is a specialized language to control CNC devices. So if you send a correct GCODE command to a board with marlin onboard, marlin will execute the command. For example if you send the GCODE command :

  G1 X10 Y10

  Marlin will control the motor to move the tool at position X=10mm and Y=10mm

  So, we have some commands to move a tool on X and Y axis. On BrailleRAP the X axis is the motor on the left. This X motor move the two trolleys in the direction of the width of the sheet of paper. The Y axis is on the right motor. The right motor move the sheet of paper in and out. If you send the G1 X10 Y10 command to a BrailleRAP, marlin will move the Braille stylus 10 mm from the left side and 10 mm from the top side of the sheet.
  

  Now we need to have some sensor to tell marlin where is the left side and the top side. This is where we use end switches. On BrailleRAP we have 2 end switches, one is activated when the trolleys are on the left side, the another is activated when the paper sheet is engaged in paper rolls.

  With the two end switches, we have 2 sensors to detect the trolleys position and paper sheet position. So we can use the GCODE G28 command which is the homing command. G28 X tell marlin to move the X axis until it detect some change on the X endswitch. G28 Y tell marlin to move the Y axis until it detect some change in the Y endswitch. As usual in software it's a bit more complex, but with these 2 commands G28 X and G28 Y we can detect the top left corner of the sheet and define this corner to be X=0 and Y=0.

  So has we have A4 sheets of paper wich are 210mm x 297 mm 

  X=210 and Y=0 is the top right corner of the paper sheet.

  X=0 Y=297 is the bottom left corner of the paper sheet.

  X=210 Y=297 is the bottom right corner of the paper sheet.

  At this time with Marlin firmware we have some commands to find the left top corner of the paper sheet, and  to move the Braille stylus on the trolley at any given position on the paper sheet.
  

  The next thing is to make a dot. The Braille stylus is on the top of an electromagnet

  The electromagnet is wired on the board on the heatbed connector.  This connector is also used to control spindle motor of CNC in marlin. We have configured marlin to use this connector as an on/off connector for the 12V. So if you send the GCODE command M3 S1, marlin will give 12V current to the electro magnet for a short period of time (50ms). As the electro magnet receive 12V current, it move quickly upward and pinch the sheet of paper between the Braille stylus and the anvil. That's it we just made a Braille dot on the paper.

  The electromagnet is off, the Braille stylus is down.  We can move the trolleys over the paper

  The electromagnet is on. The Braille stylus move upward and pinch the paper in the anvil.

  Let sum up where we are at this point, if we send the following GCODE program to a BrailleRAP :

  G28 X

  G28 Y

  G1 X10 Y20

  M3 S1

  will obtain a Braille dot a 10mm from the left, 20 mm from the top. let's eject the paper sheet from the BrailleRAP

  G1 X10 Y297

  you can now get the paper sheet.

  What we start to understand, BrailleRAP is not a Braille embosser it is just a Braille dot machine, if you want to emboss some Braille text you need to send the GCODE commands to emboss all the dots one after one and at the correct position.

  ... Read more »

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