Caster Wheel Holder

The caster wheel holder receives a 5/8 inch (16 mm) ball bearing or marble.

Hardware sources:

Amazon - 5/8" ball bearing

Node Motor Shield Holder

The motor shield holder receives a Node Motor Shield. A NodeMCU plugs into the motor shield.

Hardware sources:

Amazon - Node Motor Shield

Amazon - NodeMCU

Battery Holder (4 x AA)

The battery holder receives another battery holder for 4 AA batteries.

Hardware sources:

Adafruit - 4xAA Battery Holder

Sparkfun - 4xAA Battery Holder

Power Plug

The power plug is used to connect the batteries to the motor shield. Standard male Dupont pins are crimped to the wire ends of the battery holder and pushed into the power plug. A drop of Crazy Glue is used to keep the pins from coming out. Pay close attention to wire polarity.

Hardware sources:

Amazon - male Dupont pin


Rubber bracelets can be fitted on the wheels to give the wheel more traction.

Hardware sources:

Amazon - rubber bracelets

Motor Holder

The motor holder receives a yellow geared motor.

Hardware sources:

Addicore - geared motor

Adafruit - geared motor

Motor Holder Cap

The motor cap snaps on the top of the motor holder after a motor and wires are inserted into the motor holder.

Source Code

Download the source code to drive BERT at our github page.