I had read the design
I got a 3D pen too but I did not want to do much electronic modification on it.
As I read the comments, I think "Carlos Russo" is a good design, so I make this design.
+++++ Construction +++++++++++++
According to my CNC, I can get a piece of acrylic as a clip to install this 3D pen module.
I secured a 9g Servo with the Servo Mount Holder Bracket and mount on that acrylic sheet.
A rubber wheel was screwed on the aervo arm, in order to give some cushion effect (friction) when the servo "press" the button.
There are some plastic washer between the servo and the acrylic sheet, to adjust the thickness of the clip.
I think this is quite a simple design and u can refer to the video.
+++++ GRBL Servo +++++++++++++++
BTW, my CNC using "GRBL Servo+" instead of using GRBL
For my detail, please refer to the link.
++++ Inkscape + laser plugin +++++++++++++++
I am using inkscape to produce G-code, I use "laser engrave plugin" which turn on the laser equal to turn on the servo, the feed rate actually can be adjusted by the 3D pen itself.