Connect to Your Device

NXTKB keyboards can work over USB or Bluetooth. For a new keyboard, start with USB first because it is the fastest way to confirm that both halves are powered and the keyboard sends normal input.

Before You Start

• Turn on both keyboard halves.
• Use the left half as the main half for USB connection and Bluetooth output.
• Keep the right half powered on. It sends its input through the split connection.
• Open Keyboard & Mouse Test when you want to confirm what the browser receives.

USB First Check

USB is the most reliable first test.

1. Turn on both halves.
2. Connect the left half to your computer with a USB-C cable.
3. Open Keyboard & Mouse Test.
4. Press keys on both halves.
5. If your keyboard has a mouse layer or trackpad, test mouse buttons, wheel events, and pointer movement too.

If key events appear in the tester, the keyboard is sending input correctly.

Bluetooth Pairing

Use Bluetooth after the USB check works.

1. Turn on both halves.
2. Select the Bluetooth slot you want to use, if your keymap exposes BT_SEL 0 through BT_SEL 4.
3. If that slot was paired before, clear it with BT_CLR.
4. Open Bluetooth settings on your computer, phone, or tablet.
5. Find the keyboard name and pair with it.
6. Disconnect USB, or switch output away from USB if your keymap has an output toggle key.
7. Test typing again in Keyboard & Mouse Test.

The exact Bluetooth control keys depend on the keymap. Check your model’s keymap page if you are not sure where BT_SEL, BT_CLR, or output toggle keys are:

• Ferris Sweep Pro Keymap
• Ferris Sweep Keymap

Reconnect or Switch Devices

ZMK keyboards can store multiple Bluetooth profiles. To switch devices:

1. Select the target Bluetooth slot with BT_SEL.
2. Wait a few seconds for the keyboard to reconnect.
3. If it does not reconnect, remove the keyboard from the target device’s Bluetooth list, clear the slot on the keyboard, and pair again.

USB usually takes priority while plugged in. If you want to use Bluetooth, disconnect USB or use your keymap’s output toggle key.

Troubleshooting

Problem	What to try
Nothing types over USB	Confirm both halves are powered on. Try another USB-C cable and connect the left half directly to the computer.
Left half works but right half does not	Turn on the right half, then power-cycle both halves.
Bluetooth pairing fails	Verify USB input first, clear the selected Bluetooth slot with BT_CLR, remove old pairings from the host device, and pair again.
Keyboard appears paired but does not type	Check whether USB is still selected or plugged in. Select the Bluetooth slot again and wait for reconnection.
Mouse or trackpad events are unclear	Use Keyboard & Mouse Test to inspect mouse buttons, wheel events, and pointer movement.

If USB input works but Bluetooth repeatedly fails, flash settings_reset once to clear stored ZMK settings, then flash the normal firmware again. See How to Flash a Firmware.