# For Spirograph Pyrograph Instructable ''' Created 09/10/2021 This version: 06/11/2022 for inclusion with an Instructable This version creates simple (circular paths) hypocycloids on a white background for Simple Coasters Output is controlled by setting the boolean do_print output is jpeg image with spirograph parameters embedded in file name and GCODE set to match my set up for 100mm coasters Most parameters are in global variables for simple (non-GUI) use As such it is the sort of program we used to write in the 1970s. Set the parameters - run the program - get the output - repeat : simples! @author: Dr Alan J Green ''' # get some libraries import sys import wx import math import os from pathlib import Path ####### # Global variables!!! ####### r_static = 200 # radius of static wheel - should be integers! r_rotate = 50 # radius of rotating wheel pens = [65, 50, 35] # pen position(s) in Python list steps = 500 # number of line segments to draw do_print = False # set to false to just see pattern and decide whether to print #do_print = True # uncomment to set to true to get jpeg and GCODE my_directory = "d:/dev/Eclipse/results_op/Instruct/Laser/coasters-2/" burn_x = 95 # size of object (mm) burn_y = 95 # size of object (mm) # offsets should match those used for axis drawing burn_x_os = 11 +10 # laser offset (mm) add 10mm border burn_y_os = 58 +10 # laser offset (mm) add 10mm border burn_z = 100 # focal length of laser (mm) burn_thick = 3 # thickness of material (mm) class drawSpiro_SC(wx.Frame): ''' In this code I am just using wx to provide a Frame (a window) which is set as a paint device context . I have not set up a GUI and there are no events or event handlers +++++++++ This is not supposed to be an example of Good Programming Practice It is more of a scribbling block to play with the parameters prior to writing a full spirograph application. I have added an output function to get jpegs and GCODE which can be switched on and off by setting the global do_print. ''' def __init__(self, parent, title): ''' Constructor ''' super(drawSpiro_SC, self).__init__(parent, title = title, size = (1000,1000)) self.InitUI() def InitUI(self): self.Bind(wx.EVT_PAINT, self.OnDraw) self.Center() self.Show(True) ''' output files use '/' and try to use pathlib to get Windoze to play nicely probably shouldn't create the directory if NOT _save_frames ''' # ===================================================== # some stuff to make GCODE files # ===================================================== def GcodePreamble(self): lines = [ "; gcode generated by hypocycloid generator", "; bounds: X116 Y163", "; (size of coaster + laser mount offset)", "; ajg 2022" ] return(lines) def GcodeSetup(self): lines = [ "G90", # absolute positioning "G21", # work in mm "M106 S0", # laser power (via fan control pwm) to 0 f'G0 Z{burn_z + burn_thick}', # raise head to laser focal distance "G28 X Y" # home x & y axes ] return(lines) def GcodeTail(self): lines = [ "M106 S0", "; end code" ] return(lines) def FrameSave(self, file_name): # print(op_file) ''' output files use '/' and try to use pathlib to get Windoze to play nicely probably shouldn't create the directory if NOT _save_frames ''' file_path = my_directory # check and make directory if necess if not os.path.exists(file_path): os.makedirs(file_path) op_file = f'{file_path}{file_name}' f_path = Path(op_file) context = wx.ClientDC(self) memory = wx.MemoryDC() x, y = self.ClientSize # bitmap = wx.EmptyBitmap( x, y, -1) # generates depreciation warning bitmap = wx.Bitmap( x, y, -1) # is this empty? Does it matter if we are doing to blit the image into it? memory.SelectObject(bitmap) memory.Blit(0, 0, x, y, context, 0, 0) # memory.SelectObject(wx.NullBitmap) # from the tutorial, not sure what it does ? empty wxBitmap object # possibly needed for GUI driven program to erase previous drawing bitmap.SaveFile(str(f_path), wx.BITMAP_TYPE_JPEG) # ===================================================== # The drawing function # draws to screen, and if set, to GCODE file # ===================================================== def OnDraw(self, e): # e would be the event if this were event driven! global do_print # allows us to change its value ''' hypocycloids http://www.mathematische-basteleien.de/spirographs.htm ''' dc = wx.PaintDC(self) dc.SetBackground(wx.Brush(wx.WHITE)) dc.Clear() dc.SetPen(wx.Pen(wx.BLACK, 2)) # general case two circles # each with radii r_static and r_rotate # (big and small in a real plastic spirograph) # r_static and r_rotate set in global variables # centre of static ring xCenter = 490 # centre needs tweaking yCenter = 480 # not sure why! # drawing parameters # steps set in global variables passes = math.lcm(r_static, r_rotate)/r_rotate #number of rotations to return to start (2pi cancelled out!) step = (2.0 * math.pi) / (steps/passes) # ============================= # a quick run to get the max dimension for scaling # not clever programming, but # if it ain't broke, don't fix it # ============================= max_d = -1000 min_d = 1000 p = max(pens) n = steps for n in range(1, steps+1): t = n* step x = ((r_static-r_rotate) * math.cos((r_rotate/r_static)*t)) + p*math.cos((t*((1-r_rotate/r_static)))) y = ((r_static-r_rotate) * math.sin((r_rotate/r_static)*t)) - p*math.sin((t*((1-r_rotate/r_static)))) max_d = max([x, y, max_d]) min_d = min([x, y, min_d]) plot_size = max(max_d, (-1*min_d)) scale = .9 * (500/plot_size) # not a big fan of hard coding this # ============================= # set pyrography burning paramaters # ============================= b_xSize = float(max(burn_x, burn_y)) b_ySize = b_xSize b_xMin = burn_x_os+ .5 * (burn_x - b_xSize) b_yMin = burn_y_os + .5*(burn_y - b_ySize) b_xCent = b_xMin + b_xSize/2.0 b_yCent = b_yMin + b_ySize/2.0 b_Scale = (b_xSize/max_d) * 0.9 # ============================= # set up for saving files # ============================= if do_print: # make a file name from the parameters s_r_static = f"{r_static}" s_r_rotate = f"{r_rotate}" fn_jpeg = f"{s_r_static}-{s_r_rotate}-{len(pens)}.jpeg" fn_gcode = f"{my_directory}{s_r_static}-{s_r_rotate}-{len(pens)}.gcode" # ============================= # create and open gcode file # ============================= f_out_gc = open(fn_gcode, 'a') for s in self.GcodePreamble(): f_out_gc.write(f'{s}\n') for s in self.GcodeSetup(): f_out_gc.write(f'{s}\n') for p in pens: #start point t= 0 * step x = ((r_static-r_rotate) * math.cos((r_rotate/r_static)*t)) + p*math.cos((t*((1-r_rotate/r_static)))) y = ((r_static-r_rotate) * math.sin((r_rotate/r_static)*t)) - p*math.sin((t*((1-r_rotate/r_static)))) #translate and round for plotting x1 = int( (scale * x) + (xCenter +.5)) y1 = int( (scale * y) + (yCenter +.5)) ''' Do the GCODE thing ''' if do_print: # move head to start and turn on laser b_x = (x/2)*b_Scale + b_xCent b_y = (y/2)*b_Scale + b_yCent f_out_gc.write(f'G0 X{b_x:06.2f} Y{b_y:06.2f} F200 \n') f_out_gc.write(f'M106 S255\n') for n in range(1, steps+1): t = n* step x = (((r_static-r_rotate) * math.cos((r_rotate/r_static)*t)) + p*math.cos((t*((1-r_rotate/r_static))))) x2 = int((scale * x) + (xCenter + .5)) y = (((r_static-r_rotate) * math.sin((r_rotate/r_static)*t)) - p*math.sin((t*((1-r_rotate/r_static))))) y2 = int((scale * y) + (yCenter + .5)) dc.DrawLine(x1, y1, x2, y2) x1 = x2 y1 = y2 ''' Do the GCODE thing ''' if do_print: b_x = (x/2)*b_Scale + b_xCent b_y = (y/2)*b_Scale + b_yCent f_out_gc.write(f'G0 X{b_x:06.2f} Y{b_y:06.2f} F200 \n') if do_print: # turn off laser f_out_gc.write(f'M106 S0\n') if do_print: self.FrameSave(fn_jpeg) # Tail the gcode file with turn off the laser for s in self.GcodeTail(): f_out_gc.write(f'{s}\n') f_out_gc.close() if not f_out_gc.closed: f_out_gc.close() do_print = False if __name__ == "__main__" : app = wx.App() drawSpiro_SC(None, 'hypocycloid') app.MainLoop()