Teaching a laser cutter to draw

A few weeks ago I went to the mini maker faire in Stockholm and I wanted to show of the laser. Due to safety concerns I couldn’t run the laser out in public, but to be able to show of the CNC capabilities I built a penholder.

It is a quite simple build made out of wood, some plastic from an old cutting board, a few screws and a 9g servo. The servo is controlled by an Arduino, when the signal that would normally turn the laser diode on is high the servo is set to an angle that pushes the pen against the paper. The design was inspired by the brush holder on the WaterColorBot by Evil Mad Scientist. In their design the pen is lifted up by the servo rather then being pushed down like I did it. I don’t know what is best but it works both ways.

jenslabs.com

31 maj, 2014

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9 svar till ”Teaching a laser cutter to draw”

Paul

januari 28, 2015 at 2:06 f m

Did you have to modify the gcode at all?

GillaGilla

Svara
1. jenslabs.com
  
  januari 28, 2015 at 6:05 f m
  
  I have to remove an empty line at the start of the gode file. Open in a text editor and delete the empty lite and save.
  
  GillaGilla
  
  Svara
  1. Paul
    
    januari 28, 2015 at 11:23 f m
    
    Jens,
    Thank you for the prompt response! I am still having some problems getting my servo to work. Are you powering the servo from the arduino 5v or a separate power supply? And do you have the signal wire from the servo connected to the spindle on/off? Sorry for the noob questions!
    
    Paul
    
    GillaGilla
  2. jenslabs.com
    
    januari 28, 2015 at 1:11 e m
    
    I don’t remember how I did it but I would say that it should be possible to power the servo directly from the Arduino +5V if it’s a small servo. The signal is indeed the spindle on/off. If you want to test the servocontrol you can always emulate spindle on/off by just connecting the input wire to either gnd or +5V to verify that the servo behaves as expected. Another word of advice, if I would have done the build again I would design the penholder so that the servo lifts the pen of the paper rather then pushing it down.
    
    GillaGilla
Paul

januari 28, 2015 at 2:28 e m

Thank you! I did some digging around and found this: https://github.com/grbl/grbl/issues/220
flashed my nano – connected signal to A4 and now Z5 and Z0 control the servo! Man, thanks a million for the laser build and for this!

GillaGilla

Svara
1. jenslabs.com
  
  januari 28, 2015 at 3:14 e m
  
  You are most welcome, great to hear that you got it up and running. I would love to see a picture of your build if you have one. You can send it to my email if you want. jenslabs@gmail.com
  
  GillaGilla
  
  Svara
  1. Paul
    
    januari 28, 2015 at 4:15 e m
    
    Well I spoke too soon…. The Grbl 0.8a branch does not seem to like Universal Gcode Sender – does not show any motor movement. And only shows settings to $9?!?!?! Oh well, back to the drawing board.
    
    GillaGilla
  2. jenslabs.com
    
    januari 28, 2015 at 4:17 e m
    
    You understood that I have a separate Arduino only controlling the servo movement based on the spindle on off signal from the Arduino running the grbl software?
    
    GillaGilla
Paul

januari 28, 2015 at 4:20 e m

Ahhhhhh, now I see the light. Thanks, I will try it and let you know!

GillaGilla

Svara