Picture of CNC Eggbot
When I discovered the cool eggbot art here on instructables and egg-bot.com i knew what my next gadget would be:-D
But i can't spend 200 bucks for it at the moment. So i decided to build it on my own!
In the following steps I will outline the basic design of the original egg-bot and show you my approach of building it.

Step 1: The original egg-bot

Picture of The original egg-bot
The original egg-bot features two steppers for rotating the egg and moving the pen, lifting the pen is done by a small servo.
The controller for the motors is the EBB (EiBotBoard or EggBotBoard i think), it is a controller/driver for two steppers and a servo which is based on the UBW (USB bit whacker) board which is basically a usb device for controlling multiple servo/stepper motors (http://www.schmalzhaus.com/EBB/ ). Together with a driver, and the correct firmware one can send a set of defined commands to it to move the motors. Eggbot programs are basically a series of commands to rotate the egg/pen and to lift the pen. There exists a inkscape Plugin to generate UBW-Commands for the eggbot.

And that's the part I didn't like so much about the eggbot: it is using a pretty custom set of software/hardware tools to operate, although there are already plenty of  other great tools for these CNCish kind of tasks.

Recently I have built a desktop cnc milling machine (http://www.instructables.com/id/Easy-to-Build-Desk-Top-3-Axis-CNC-Milling-Machine/) with the appropriate driver (http://www.instructables.com/id/Easy-to-build-CNC-Mill-Stepper-Motor-and-Driver-ci/).
 So I decided to alter the eggbot design a little bit, so that it is driven with three stepper motors (without a servo). Therefore it can be controlled with any cnc software (and I could reuse my old controller/motors)
agis683 years ago
maybe i missed but where i can see the circuit or circuits? (schematics)
derwassi (author)  agis683 years ago
As i mentioned in step 6, i first used those: http://www.instructables.com/id/Easy-to-build-CNC-Mill-Stepper-Motor-and-Driver-ci/
but then upgraded to linisteppers: http://www.piclist.com/techref/io/stepper/linistep/index.htm
They didn't work very well either, but I think that't because of the crappy steppers... I haven't included anything here, because it's covered in more depths and more completely in the referenced pages.
The stepper controller is directly driven from the paralell port, so no need for any further circuitry.
agis68 derwassi3 years ago
thnx for the reply
die_Niam4 years ago
Very cool instructable! Egg-celent!!
Oh wow..guess the yolk's on us!
-shtoink-4 years ago
It might be worth trying to find a way to stiffen up the arm somehow. In the video you can see that some error is introduced due to wobble. This wobble could possibly be from material, glue joints, or motor mount. In the grand scheme of things, it's minor, but still worth adding to the list.

I wonder if making the entire arm from a long hinge and trimming to length might take care of stiffening. The downside is that it adds more mass to be moved around.

This has now been added to my future project list. Thanks!
skatewinger4 years ago
Nice work, and good pointers to other ideas. Thank you for posting this.