The robot is based on the original design of Evil Mad Scientist 

Features:

The Sphere-O-Bot is a simple 2 axis drawing machine that can draw on most spherical surfaces. You can use it to decorate balls or eggs.  This design also features the regular JJrobots electronics (the same we have used in all our robots). So you can create this robot or any other just simply printing new 3D printed parts and uploading the appropriate code.

The Sphere-O-bot is adjustable, and is designed to draw on all kinds of things that are normally "impossible" to print on. Not just eggs but ping pong balls, Christmas ornaments, light bulbs, and (yes) eggs (duck, goose, hens...).

The Sphere-O-bot frame was designed by Attila Nagy and slightly modified by JJrobots. The pen and egg motors are high-torque precision stepping motors, and the pen lift mechanism is a quiet and reliable servo (SG90) motor.

The Sphere-O-bot KIT

The KIT includes:

• 2x 623 ball bearings
• Threaded steel rod (3mmØ,80mm length)
• 1x compression spring (4,5mmØ, 10 mm length)
• 2x 1.8deg HIGH QUALITY NEMA 17 Stepper motors (40mm length) (4.4Kg/cm torque)
• Motor cables (14+70 cms long) (not in the photo)
• USB cable
• 1x SG90 servo
• Arduino Leonardo compatible
• B-robot Brain Shield 
• 2x A4988 Stepper motor drivers
• Power supply 12v/2A
• 4x 6mm M3 bolts
• 14x 15mm M3 bolts
• 4x M3 nuts
• 2x 20mm Suction Cups
• 1x M3 wing nut
• 1x Marker PEN