How to Build a Motorized Car with Circuit Cubes: Step-by-Step Guide

Quick answer

To build a motorized car with Circuit Cubes, connect a Bluetooth Battery Cube to a Cubit Motor Cube using the included wires, mount the motor so its axle drives a wheel, and secure everything to a brick-built chassis. The Bluetooth Battery Cube powers the motor; switch it to ON for immediate driving or BLUETOOTH to pair with the Circuit Cubes App for remote control. Most builds take about 30 minutes and need only a handful of parts.

Building a moving toy car from scratch is one of the most satisfying first projects you can do with Circuit Cubes. The system is designed so that power, control, and motion snap together without soldering or complex wiring. You supply the bricks and wheels; Circuit Cubes supplies the brain and muscle.

This guide walks through the exact steps to assemble a reliable, drivable car. You will connect the Bluetooth Battery Cube to the Cubit Motor Cube, build a chassis that holds the motor securely, and align the drive wheel so the car actually moves forward instead of spinning in place. Each step includes a checkpoint so you can catch problems early.

What you need before you start

Gather your core electronics first: one Bluetooth Battery Cube and one Cubit Motor Cube. The Bluetooth Battery Cube has a three-position switch (ON/OFF/BLUETOOTH) and a built-in wireless radio for app control. The Cubit Motor Cube contains a geared motor that reduces speed to about 160 RPMs, which is slow enough to drive a toy car with useful torque rather than just spinning wheels.

For the body, collect standard building bricks, at least two axles (the Cubit Motor Cube includes custom 10mm and 14mm axles), and four wheels. You will also need a few plates and bricks to form a rigid chassis. A 4x8 plate makes a good foundation because it gives you a wide, stable base for the battery and motor.

• Check that your Bluetooth Battery Cube is charged before building. A dead battery is the most common reason a new build does not move.
• Keep the motor wires clear of any moving parts. They are flexible but can get caught in a wheel if left loose.

Step 1: Build a rigid chassis

Start by building a flat, sturdy base. Use a 4x8 plate as the bottom layer, then add bricks around the edges to create a shallow tray. This tray will hold the Bluetooth Battery Cube and keep it from sliding when the car moves. A rigid chassis is important because a flexing frame will misalign the motor and cause the car to veer or stall.

Leave a gap at the rear of the chassis for the motor. The Cubit Motor Cube has three ports around its body, so you can route wires from different angles. Plan which port you will use before you seal up the chassis.

• Common mistake: building the chassis too narrow. If the battery overhangs the sides, the car will tip over in turns.
• Checkpoint: press down on the chassis corners. It should feel solid, not springy.

Step 2: Mount the Cubit Motor Cube

Attach the Cubit Motor Cube to the rear of the chassis using bricks or a bracket you build from plates. The motor's output shaft should point toward the rear axle location. Because the motor uses internal planetary gears to deliver about 160 RPMs, it produces more torque than a bare motor of the same size. That torque is what lets the car climb over small bumps and carpet edges.

Secure the motor on at least two sides. A motor held by only one stud will twist under load and strip the connection. If your chassis design allows, build a small cradle that wraps around the motor body.

• Common mistake: mounting the motor so the shaft rubs against a brick. Leave a small gap around the shaft.
• Checkpoint: try to wiggle the motor with your finger. It should not move more than a millimeter.

Step 3: Connect the motor to the Bluetooth Battery Cube

Plug one end of a wire into any of the three ports on the Cubit Motor Cube, and the other end into the matching port on the Bluetooth Battery Cube. The ports are keyed, so they only fit one way. Do not force a connector. Once connected, the circuit is complete and the motor will run when the battery is switched on.

Route the wire along the chassis and tuck it under a brick if possible. A loose wire can catch on the ground or wrap around an axle. If you need a longer run, use a second wire and a pass-through brick, but keep the total number of connections to a minimum for reliability.

• Common mistake: plugging the wire into the battery while the switch is ON. Always switch OFF before connecting or disconnecting.
• Checkpoint: switch the battery to ON. The motor should spin immediately. If it does not, reseat both connectors.

Step 4: Install the drive axle and wheels

Slide a custom axle into the motor's output shaft. The Cubit Motor Cube includes 10mm and 14mm axles; use the shorter one for a compact car and the longer one if you need to clear wide tires. Attach a wheel to the axle and secure it with a friction pin or a small brick. This wheel is your drive wheel.

Add a second axle at the front of the chassis for the non-driven wheels. Make sure all wheels are the same diameter. If the front wheels are larger than the rear, the car will tilt and the drive wheel may lose traction.

• Common mistake: pushing the wheel on too far so it rubs against the motor body. Leave a tiny gap.
• Checkpoint: spin the drive wheel by hand. It should turn the motor shaft smoothly with no grinding.

Step 5: Power up and test drive

Set the car on a smooth floor and switch the Bluetooth Battery Cube to ON. The LED on top turns green, and the motor should drive the car forward. If the car moves backward, simply flip the motor's wire connector or rotate the motor 180 degrees in its mount. If it does not move at all, check that the drive wheel is touching the ground and that the battery is charged.

For app control, switch to BLUETOOTH. The LED flashes blue. Launch the Circuit Cubes App, open the Bluetooth screen by tapping the icon in the upper right, and pair your device. You can then drive the car remotely and adjust speed.

• Common mistake: testing on thick carpet. Start on a hard, flat surface to confirm the build works.
• Checkpoint: the car should travel at least a few feet in a straight line. If it circles, check that the front axle is parallel to the rear axle.

Build steps at a glance

1. Build a rigid chassis: Use a 4x8 plate as the base and add bricks to form a tray for the battery. A flexing chassis misaligns the motor. Checkpoint: the chassis should feel solid when you press the corners.
2. Mount the Cubit Motor Cube: Attach the motor to the rear of the chassis, securing it on at least two sides. Leave a small gap around the output shaft. Checkpoint: the motor should not wiggle when you push it.
3. Connect motor to Bluetooth Battery Cube: Plug a wire into any of the three motor ports and the matching battery port. Route the wire along the chassis and tuck it away. Checkpoint: switch to ON. The motor should spin immediately.
4. Install drive axle and wheels: Slide a custom axle into the motor shaft, attach a wheel, and add a front axle with matching wheels. Checkpoint: spin the drive wheel by hand; it should turn the motor smoothly.
5. Power up and test drive: Switch to ON for forward motion or BLUETOOTH to pair with the app. Test on a hard, flat floor first. Checkpoint: the car should travel a few feet straight. If it circles, check axle alignment.

Circuit Cubes parts used in this build

• Bluetooth Battery Cube: The Bluetooth Battery Cube has built-in wireless connectivity. The switch has 3 positions: ON/OFF/BLUETOOTH. Move it to ON and the LED turns green; move it to BLUETOOTH and the LED flashes blue waiting to be paired with your device. This is the power and control center of your car. ON gives you simple forward motion; BLUETOOTH lets you drive the car from the Circuit Cubes App.
• Cubit Motor Cube: Cubit Geared Motors are compact and powerful. The tiny planetary gears inside reduce the high-speed motor to about 160 RPMs to provide torque to gears, wheels, etc. Three ports around the Motor allow maximum versatility to connect the wires from the Bluetooth Cube. The 160 RPM gearing gives your car enough torque to move without being uncontrollably fast. The three ports let you route wires cleanly around your chassis.
• Plate - 4 x 8 - #3035: Included: Plate, 4x8, #3035, Qty 1. A 4x8 plate makes a rigid, flat foundation for your chassis, which keeps the motor and battery aligned so the car drives straight.

Once your car drives reliably, experiment with gear ratios, wheel sizes, and body shapes. The same Bluetooth Battery Cube and Cubit Motor Cube can power many other builds, so you can reuse them as your designs get more ambitious.