I wanted to create an animatronic character. I had ideas for a few chracters, but wanted to do something different than the standard huminoid animatronic figures.
I decided on a piranha plant from the Super Mario series. Let's a go!
The initial challenge I wanted to tackle was making the stem that could bend at any of the 360 degrees. The basic design comes from a tail mechanism, the only difference with this is the need for the stem to be firm enough to stand on it's own, but flexible enough to bend. I picked a 1/4" pneumatic tube as the main spine material. I 3D printed vertebrae discs with holes to feed the strings through. These strings will shorten to bend the stem. The initial concept was made without stepper motors, but used as a puppet to confirm the concept worked. After the concept was validated, two stepper motors were added that control the bending, one controling front and back, the other left and right.
One issue with the first stem was the 1/4" pneumatic tube was too stiff to bend with the 34Nmm stepper motor above. I upgraded the stepper motor to a 420Nmm one, this provided much better results.
Another issue was the stem base. When the strings would lose tension during bending, they sometimes fell off the pulleys. I changed the design to the concept on the right with channels instead of pulleys. The new stem base was much simpler and easier to print. Simpler is better most of the time.
The next challenge was to create the jaws. For the initial design, I was going to 3D print the whole head. However after contemplating how the jaws would move, people would be able to see the jaws disapearing into the bottom half of the head. This would not be very organic and not be convincing its a real plant.
I changed it so just the jaws are 3D printed, the rest of the head would be a hollow foam ball, like that of a puppet head. The jaws are controlled by a single servo with them both paired by gears to allow them to open/close equally. It took 3 iterations with small changes in each to get to this concept seen below.
Super Mario often has brick blocks lying everywhere with coins or other suprises in them. The purpose of this block is to hide the electrical components. There are also ultra-sonic sensors at each face of the block to detect motion and allow the plant to bend in that direction.
The skeleton of the plant can be seen below with all the electronics.
Here you can see the piranha plant in action with the workings of the individual components.
This is still a work in progress. The next steps are:
- Making a better stem to replace the 1/4" pneumatic tube.
- Commonizing the scale of all the components.
- Working with the foam/felt to hide the stem and head.
The initial challenge I wanted to tackle was making the stem that could bend at any of the 360 degrees. The basic design comes from a tail mechanism, the only difference with this is the need for the stem to be firm enough to stand on it's own, but flexible enough to bend. I picked a 1/4" pneumatic tube as the main spine material. I 3D printed vertebrae discs with holes to feed the strings through. These strings will shorten to bend the stem. The initial concept was made without stepper motors, but used as a puppet to confirm the concept worked. After the concept was validated, two stepper motors were added that control the bending, one controling front and back, the other left and right.
One issue with the first stem was the 1/4" pneumatic tube was too stiff to bend with the 34Nmm stepper motor above. I upgraded the stepper motor to a 420Nmm one, this provided much better results.
Another issue was the stem base. When the strings would lose tension during bending, they sometimes fell off the pulleys. I changed the design to the concept on the right with channels instead of pulleys. The new stem base was much simpler and easier to print. Simpler is better most of the time.
The next challenge was to create the jaws. For the initial design, I was going to 3D print the whole head. However after contemplating how the jaws would move, people would be able to see the jaws disapearing into the bottom half of the head. This would not be very organic and not be convincing its a real plant.
I changed it so just the jaws are 3D printed, the rest of the head would be a hollow foam ball, like that of a puppet head. The jaws are controlled by a single servo with them both paired by gears to allow them to open/close equally. It took 3 iterations with small changes in each to get to this concept seen below.
Super Mario often has brick blocks lying everywhere with coins or other suprises in them. The purpose of this block is to hide the electrical components. There are also ultra-sonic sensors at each face of the block to detect motion and allow the plant to bend in that direction.
The skeleton of the plant can be seen below with all the electronics.
Here you can see the piranha plant in action with the workings of the individual components.
This is still a work in progress. The next steps are: - Making a better stem to replace the 1/4" pneumatic tube.
- Commonizing the scale of all the components.
- Working with the foam/felt to hide the stem and head.