Eggbot / Sphere-o-bot / Eggduino Mods

thingiverse

This is a series of mods that I created for the JJRobots version of the EggBot. I started with the remix of the base that allowed for the vertical adjustment of the servo arm - https://www.thingiverse.com/thing:2120339. From there, I wanted to make the centering axis more robust so I beefed up the hardware. Unfortunately, this led to a bastardized mix of metric and imperial parts (not my first choice, but gotta work with what's available). The centering axis has been converted to 1/4-20 hardware. The bearings are R188-2Z (.250" ID x .500" OD x 3/16"). Threaded rod is 1/4-20 x 3". Other mods: 1. Cups - to be printed in flexible filament (I used SainSmart TPU). The stepper cup is secured with an M5x12mm flat-head screw. The centering cup is secured using a 1/4-20 nylon locknut. 2. Inner Axle Carrier - I recessed the bearing and allowed clearance for the centering cup to nest into the right side of the frame in order to gain a larger workspace that would accommodate longer objects. Again, the cavity is designed for an R188-2Z bearing (1/4" ID x 1/2" OD x 3/16"). 3. Stepper Coupler - I modified the coupler on the stepper motor to receive the stepper cup and to allow for adjustment of the coupler and cup to accommodate longer and shorter objects as needed. Use an M5 nut to secure the stepper cup and an M3x10mm screw and nut to secure the coupler to the shaft of the stepper motor. Long and short versions of the part are included. 4. Outer Axle Carrier - Modified to accept a R188-2Z bearing. 5. Base - I designed a base to be printed in flex filament for the unit to sit on to be non-slip and cover up the innards. The dimensions compensate for the inherent shrinkage encountered when using flex filament. If you decide to print this in another material, you may need to reduce the part size slightly to achieve an interference fit with the frame. 6. Servo Wire Strain Relief - I noticed as the servo arm was going through its motions that the wires were being subjected to a lot of extraneous bending that would eventually lead to failure so I designed this to stabilize the cables. Full thing can be found here: https://www.thingiverse.com/thing:4287369 (bare wire and cable-wrapped versions included) 7. I redesigned the knob to accommodate a 1/4-20 nut and added a plug to clean things up. 8. The vertical arm was modified to use (2) MR125Z bearings and a M5x45mm screw, (4) washers and a locknut. The horizontal arm (pen holder) was modified to work with the same hardware. 9. Electronics Case - I modified the lid on Spretrep's case (https://www.thingiverse.com/thing:3186126) to be a little deeper and changed the vent design.