paenian/bb8

Trying to make a printed BB8 that's strong and accurate.

bb8

Trying to make a printed BB8 that's strong, fast and accurate.

Shell

I want a full spherical shell, that is strong, printable, and provides easy access to the innards.

The new plan is to print endcaps, then use a thermoformer to create petals connecting them. I'll also create printable petals, so that I can make a thermoformed mold with some details. I'll probably end up printing all 6 shells, then making molds.

The hamster is now integrated into the shell, as it's an axle-drive bot; current

##Current State Controller is on its way - it can read all the potentiometers for body and head movement, but I need to add a couple buttons or a rocker for body spin.

Old shell

• Old design is a rombicuboctahedron, which has 18 square faces and 8 triangular faces.
• Each square face, when oriented for printing, fits in a 180x180x180mm cube.
• The parts print on their edge - so there's no need for support material.
• This shell is inordinately heavy, and the magnetic triangle joints are not strong enough.
• No longer developing this, in favor of the axle-drive bot.

The parts are joined by screws on the center of their face, with washers at the corners biscuit-joint style.

Old Hamster

For the hamster, I plan to make an omniwheel robot. I have no experience with robot building.

Right now I don't have any plans for the head.

I'll be using an Arduino 101: https://www.arduino.cc/en/Main/ArduinoBoard101

• because I think that the internal IMU and faster processor will make my bb8 more realistic. Existing designs seem too wobbly.
  • I will probably need another accelerometer for the head, when I get there.

First step is to hook that up to a Rover 5 Motor Controller:

• https://github.com/sparkfun/Rover5_Motor_Driver_Board
• http://smile.amazon.com/Motor-Controller-Channel-4-5A-4-5-12V/dp/B00B88F2A6

Motors:

• https://www.pololu.com/product/1163

Everything Old is New Again

• Lately I like the old idea better, with a proper non-connected hamster. Some ideas.
• 3 wheels are better than 4; with 4 wheels, they need to be balanced or sprung; with 3, all wheels will always touch.
• • controlling 3 is a little harder, but it's been done.
• • http://www.open-electronics.org/how-to-build-an-omni-wheels-robot/
• stacks. Stack everything!
• • motor stack: three motors & wheels, & the motor controller.
• • balance stack: two linear stages, containing linear weights to dynamically balance BB8. Should go low.
• • • basically, the wheel stage is for moving; the balance stage fixes the inevitable wobble.
• • downforce stack: keeps the wheels pushing down, and the whole bot locked in. Might want to integrate this with the motor stack.
• • • downforce wheels should be sprung, motor stack wheels should be rigid.
• • Head stack: top stack, has the head pivot point in the center of the sphere, a counter weight,and motors to tilt and spin the head.
• • Battery, Electronics stack: contains the battery and electronics.
• • • Need two accelerometers - one on stack, one on the head.

Paul