2 🧩 Open the Box

"life is like a box of Nybble." 🔍

The actual kit contents and packaging method may be adjusted as we improve the product. This instruction will keep consistent with the current namespace.

Newest kit contents:

Early kit contents:

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, it’s 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 thorns on the pieces. Don’t sand too much, or it may affect the tightness between joints.

2.3 Screws

There are five different screws used in the kit. I’m coloring them differently to indicate their locations better. 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.

● 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.

● B is for attaching servo arms/circuit boards to the frame.

● C (flat tip) is for binding the thighs.

● E (always the longest) is for attaching the battery holder.

In later versions, the types of screws are reduced to simplify the kit content and avoid confusion.

• Screw B and D are both replaced by C.

• Screw E is canceled after a rechargeable battery is used to replace the battery holder.

For the earliest 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.

● The eight spring F is used for elastic connection in the thigh. There’s one spare unit.

● The hard short spring G is for the neck

● The soft short spring H is for attaching the battery holder.

In later versions, the types of springs are reduced to simplify the kit content and avoid confusion.

• The hard short spring G is replaced by spring F.

• The soft short spring H is canceled after a rechargeable battery is used to replace 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.

Gear	Signal	Protocol	Voltage	Motor	Bearing
Plastic	Analog	PWM	5V	Brushed	None
Metal	Digital	Serial	HV (up to 8V)	Coreless	Yes
				Brushless