Announcing The Sketch Plotter Bot!!

The UNO is here!

The sketch plotter bot is now officially on its way to construction. The sketch plotter bot will be an XY plotter using pens/markers as the drawing media.

A CNC machine

Unlike normal CNCs and plotter machines however, the sketch plotter bot will take an image file processed using Processing and sketch an artistic representation of the image instead of line art. Much like the Drawing Machine. After months of contemplations I've decided on using the Arduino platform as it seems to be the easiest to use in terms of assembly, connectivity and especially programmability.

 

The basic parts list for the project is as following:

• Arduino UNO to control the motors
• Adafruit motor shield kit for driving the following motors
• 12V 350mA 200step/rev bipolar stepper motor (2) for axis control
• Standard servo for pen lifting
• 2 used printers for mechanical parts and chassis (These are more cost effective than buying timing belts, gears and rods separately if I don't need any additional parts. They will also include some stepper motors and drivers)
• Sharpie ultra fine point markers ~1mm tip. I may consider using draft pens if these don't work out well.

I just received the arduino, motors and motor shield kit in the mail today and the arduino proves itself to be as good as it claims. In minutes of troubleshooting (installing the driver and selecting the right COM port) and even fewer minutes of coding I got the on board LED to blink.

Blinking LED code:

void setup()
{
  // set pin 13 as output:
  pinMode(13, OUTPUT);    
}

void loop()
{
    digitalWrite(13, HIGH);
    delay(200);
    digitalWrite(13, LOW);
    delay(200);
}

That's it! Good riddance assembly.

Future milestone accomplishments will include videos. I just won't bother uploading a video of a blinking LED. Although the UNO only has 32kb memory it should be sufficient for plotting data. If it isn't then I'll probably resort to multistage plotting.

The next step will be controlling the 3 motors to work together to plot the image. As the motor shield cam as a kit I'll have to take some time to assemble and test it. Controlling the motors using Arduino should be a breeze though as there are libraries available for both stepper and servo motors.What are libraries you ask? Basically they're just code that you don't have to write and can use for your own convenience. Don't worry I'll cover this in the next post on motor driving and control.

Other projects/products worth looking at are:

• contraptor.org open source hardware kits developed by a couple of passionate guys. The kits are pretty inexpensive for making your own CNC/plotter machine but I'm not ready to spend that kind of money yet. I'll definitely look into the xy-plotter further down the road.
• The drawing machine kickstarter page (different from the above drawing machine link) all I have to say is:

• The Incredible Egg Bot!  it's a robot that draws on eggs/spherical objects. What more do you want?
• The Makerbot Thing-O-Matic plastic 3D printer. A relatively (and I stress relatively) low price 3D prototyping machine.

And as an honorable mention, The no programming LED cube since it's so cool.

As you can see I won't go too deep into technical details or concepts in my posts to maintain focus on the sketch plotter bot itself, but feel free to ask questions in the comments. We'll be glad to answer them.

- dc