The actual kit contents and packaging method may be adjusted as we improve the product. This instruction will keep consistent with the current namespace.
2.1. Cut body pieces off the baseboard.
There might be some tar residue on the wooden pieces from laser cutting. Use a piece of wet soft tissue to clean up the board.
The functional pieces are attached to the baseboard by lightly cut tabs. Though you could pop those pieces out by hand, itβs very highly recommended that you use a knife to cut on the backside of the tabs to avoid potential damage to the middle layer, where the fiber direction is perpendicular to the surface fiber.
After taking out all the pieces from the baseboard, you are encouraged to bend and break the remaining structures on the baseboard, to understand the mechanical properties of plywood, such as anisotropic strength, elasticity, etc. That will give you confidence in later handling.
2.2. Remove pointy fibers.
Use the sanding foam to clean up any thorn on the pieces. Donβt sand too much or it may affect the tightness between joints.
2.3. Screws
There are five different screws used in the kit. Iβm coloring them differently to better indicate their locations. Not all screws are required to assemble Nybble. Not all holes on the puzzle pieces need screws. Observe the assembling animation carefully to locate them.
β A is for attaching servo arms. D (sharp tip) is for attaching servos to the frame. A and D come in each servo's accessory pouch with plastic servo arms.
β B is for attaching servo arms/circuit boards to the frame.
In later versions, it may be replaced by C to simplify the kit content. In that case, if the hole is too small for screw Cβs flat tip, use screw D to pre-tap.
β C (flat tip) is for binding the thighs.
β E (always the longest) is for attaching the battery holder.
For earlier packages, B, C and E are located in the shank board within the multi-punched blocks like this:
2.4. Springs
There are three different springs: F, G, H.
β The big spring F is used for elastic connection in the thigh. Thereβs one spare unit.
β The hard short spring G is for the neck
Itβs replaced by spring F in later versions
β The soft short spring H is for attaching the battery holder.
2.5. Servos
We are switching to a new servo manufacturer from recent batches. Previously, MG92B was used for the four shoulder joints. MG90D was used for other joints.
The new servos are differentiated by their cable length. Shorter cables are used for the neck, tail, and four shoulder joints. Longer cables are used for head tilting and the four knee joints.
For hobbyist servos, there are several fields where they can differentiate.
In the Nybble kit, we are using ODMed metal gear, digital PWM, HV servos with bearing, and brushed iron core motors. Other generic servos can still work with the OpenCat framework but may need more trials and errors for best performance.