OpenScad Micro Servo Robot Arm
by holgero, published
This design is a re-write of http://www.thingiverse.com/thing:34829 in OpenScad.
Also some of the parts were too hard to print for me, so I made them easier to print.
You will need additionally 5 micro servos 9g with their accessories, 4 small screws and a pic18F13K50 to control the servos via USB from your PC.
Either use the RoboArm.scad file and follow the instructions at the end of the file which modules you need and render them to stl files. You may want to check the diameter of the shaft of your servos and adjust the inner radius of the gripperGear (I used 2.5 mm).
Or use the stl files directly if you don't need to change anything.
Either way, slice the stl files (I used Slic3r, layer height was 0.3 mm for all parts). Don't add support, it is included in the design, but add a brim to all of the Arm-parts (I printed the Gripper without brim, but I think I was just lucky, so you probably want to add a brim to them, too).
Print the Foot, Swing, ArmSpring, Arm, ArmFront, FrontPlate and GripperGear once. Print Gripper and GripperRack twice.
Remove the support: The Swing, ArmSpring and Arm have a small support piece below the mount for the next arm, remove that. Also the holes in the side of the Gripper are not connected, cut the plastic to connect the holes.
Assemble the parts and the servos. Use the quad horn for the servo in the Foot and the small screws to attach it to the Swing. The servos in the Swing, ArmSpring and Arm use the horn with one arm. The servo in the ArmFront needs no horn, but the GripperGear.
Don't forget the FrontPlate when fixing the servo in the ArmFront, it goes between the servo and its cage.
To control the servos I use a pic18F13K50, the software (firmware for the PIC and a java program to control it) is available at github: https://github.com/holgero/PicUsbServo .