In the last post, I introduced a WeDo 2.0 project called Santa Claus model. It uses bevel gear and offset shaft to simulate the gesture of a running reindeer which drives the sled Santa Claus is riding. In this post, I will introduce another project made by the same author. It simulates a puppy running around joyfully. Take a look at this amazing project.
Both projects have one thing in common. It uses offset shafts to form leg structures, so the model will simulate the walking gesture lively. Is’t it very cute? Let’s explore its mechanical structure fist.
Structure of the Model
As Santa Claus model, Spinne model consists of two parts. Part 1 contains smart hub and motor. It connects with Part 2 with a long axis. Part 2 is the mechanical structure. I will introduce Part 1 first, followed by Part 2.
Assembly of Part 1
The purpose of Part 1 is to provide a base for motor and smart hub. In this project, the base should also be able to spin, so that the puppy model could run around it. The structure of Part 1 is designed to ensure that motor and smart hub mounts stable and firmly.
Step 1: install motor.
Step 2: install smart hub.
Step 3: install axes. In this step, Please pay attention to the beam with plate (black one) part. It not only changes the motion’s vertical position, but also makes the axis getting extra support.
Step 4: install the freely spinning base.
Assembly of Part 2
Step 1: install the gears. The design of LEGO WeDo 2.0 has ensured that those gears could align properly alone the beam. The usage of bushing ensures that the gears are fixed horizontally.
Step 2: Finishing the other part of the body. The author inserts belt wheels on each side. Those belt wheels have holes around the center and can be used to create offset shafts.
When we observe the walking gesture of animals, we could notice some interesting patterns. When one front leg moves forward, a back leg at opposite side is also moving forward, too. It is kind of like human beings, when we moves one leg forward, the hand at the opposite side will stroke forward to help our body keep balance. This gesture analysis explains why the author arranges the pegs at the opposite direction as shown in below left image.
Comparison with Other Projects
The innovative design of Spinne model could be found in other projects. We could find offset shaft structure in Santa Claus project and one guided project – tadpole. We could also find the gear transmission structure in at least one of guided project – turning.
Complete Model and Code
When I makes analysis here, what I emphasize is that we not only just learn this model, but could also apply the design method to other scenario and design our new models. That is the meaning of learning others’ model and the purpose of this post.