How to Use the Bluetooth Upgrade Kit with Your Circuit Cubes

Quick answer

Slide the Bluetooth Battery Cube's switch to BLUETOOTH, wait for the LED to flash blue, then open the Circuit Cubes App and tap the Bluetooth icon in the upper right to pair. Once paired, you can drive motors, LEDs, and switch cubes from your device instead of the physical switch.

The Bluetooth Battery Cube turns any Circuit Cubes build into a remote-controlled one. It replaces the standard battery cube in your circuit, and the three-position switch lets you choose between plain battery power and wireless control.

Setup is quick, but a few details trip people up: the switch position, the LED color, and the order you open the app. This guide walks through the whole process, from charging to driving, with the checkpoints that tell you each step worked.

What the Bluetooth Battery Cube adds to a build

The Bluetooth Battery Cube has built-in wireless connectivity. Its switch has three positions: ON, OFF, and BLUETOOTH. In ON, the LED on top turns green and the cube works like a standard battery, powering your build without any app involved. In BLUETOOTH, the LED flashes blue and the cube waits to be paired with your device.

That means the same cube covers two jobs. You can hand a build to a child in ON mode and let them use a physical switch, or flip to BLUETOOTH when you want app control. The cube is a drop-in replacement for the battery in a circuit, so no rewiring is needed.

• Green LED means battery mode, blue flashing means pairing mode.
• If the LED does not light at all, charge the cube before troubleshooting anything else.

Before you pair: charge and check the circuit

Pairing works best when the cube has a full charge and the rest of the circuit is already assembled. Build your model first, connect the motor, LED, or switch cubes, and confirm the build runs in ON mode. If it does not move in ON mode, the problem is in the circuit, not the Bluetooth connection.

Keep the cube and your phone or tablet within a few feet during pairing. If you are in a room with many wireless devices, move away from routers or other Bluetooth speakers to reduce interference.

• Test in ON mode first so you know the circuit is sound.
• Pair one cube at a time if you own more than one Bluetooth Battery Cube.

Pairing with the Circuit Cubes App

Move the switch from OFF to BLUETOOTH. The LED on top should flash blue, which means the cube is advertising itself and waiting to be paired. If it stays solid or does not light, slide the switch back to OFF and try again.

Launch the Circuit Cubes App and open the Bluetooth screen by tapping the icon in the upper right. Your cube should appear in the list. Select it and wait for the app to confirm the connection. Once paired, the app becomes your control panel for the build.

• The most common mistake is leaving the switch in ON. The cube only pairs in the BLUETOOTH position.
• If the cube does not appear, close and reopen the app before resetting the cube.

Controlling motors, LEDs, and switches from the app

After pairing, the app's on-screen controls replace the physical switch. You can start and stop a motor, change direction, and trigger LEDs without touching the build. This is where the upgrade pays off for vehicles, because steering and speed changes happen from your hand rather than by chasing the model across the floor.

The NO/NC Switch Cube is a useful companion here. In the NO position, pressing the lever arm closes the circuit; in NC, the circuit stays closed until you press the lever. When that switch is part of a Bluetooth-controlled circuit, the app handles power while the lever handles logic, so you can build projects that respond to a press rather than only to a screen.

• Label your builds if you pair more than one cube; the app list can look similar.
• Keep the app open during play. Backgrounding it may drop the connection.

When pairing fails: the three checks that fix most problems

First, confirm the switch is in BLUETOOTH and the LED is flashing blue, not green. Second, confirm Bluetooth is enabled on your phone or tablet and that the app has permission to use it. Third, confirm the cube is charged; a weak battery can flash briefly and then drop the connection.

If all three check out and the cube still will not pair, turn the cube OFF, close the app completely, wait a few seconds, then repeat the sequence. Pairing is a short-range process, so stay close to the cube during the attempt.

• Restart the cube before restarting your phone; it is faster and usually enough.
• If a second device is already paired to the cube, disconnect it first.

Bluetooth setup, step by step

1. Charge the Bluetooth Battery Cube: Charge the cube fully before pairing. A partially charged cube can flash blue and then drop the connection mid-setup. Checkpoint: the LED lights when you move the switch.
2. Build the circuit and test in ON mode: Connect the motor, LED, or switch cubes and slide the switch to ON. The LED turns green and the build should run. This proves the circuit works before wireless enters the picture. If it does not run here, fix the circuit first.
3. Switch to BLUETOOTH: Slide the switch from OFF to BLUETOOTH. The LED flashes blue, meaning the cube is waiting to be paired. Mistake to avoid: leaving the switch in ON, where the cube never pairs.
4. Open the Circuit Cubes App: Launch the app and open the Bluetooth screen by tapping the icon in the upper right. Keep your device within a few feet of the cube. Checkpoint: the cube appears in the device list.
5. Select the cube and confirm the connection: Tap your cube in the list and wait for the app to confirm pairing. The blue flashing should settle into a connected state. If it fails, close the app fully and repeat from step 3.
6. Drive the build from the app: Use the on-screen controls to run motors, change direction, and trigger LEDs. Keep the app in the foreground during play. Next step: add an NO/NC Switch Cube for press-triggered actions.

The cubes that make this work

• Bluetooth Battery Cube: The switch has 3 positions: ON, OFF, and BLUETOOTH. In ON the LED turns green and it powers your builds; in BLUETOOTH the LED flashes blue waiting to be paired. The switch position is the single most common reason pairing fails, so check the LED color before touching the app.
• NO/NC Switch Cube: In the NO (Normally Open) position, pressing down on the lever arm closes the circuit. In the NC (Normally Closed) position, the circuit stays closed until you press the lever arm to open it. It adds a physical trigger to a wireless build, so a project can react to a press as well as to the app.
• STEM Starter Kit: The kit contains a rechargeable Classic Battery, Geared Motor, and LED cubes, along with instructions for 10 suggested projects. If you already own this kit, adding the Bluetooth Battery Cube upgrades the same motor and LED projects to app control.

The Bluetooth Battery Cube is a direct swap for the battery in any Circuit Cubes build, so the upgrade costs you one switch position and a minute of pairing. Test in ON mode, flip to BLUETOOTH, pair through the app, and your models gain wireless control without a single new wire.