USB Sensor Hubs

Last updated March 27, 2026

Overview

USB sensor hubs are multi-sensor devices that connect to your Raspberry Pi via USB. Each hub contains multiple independent sensor ports, allowing you to connect several sensors through a single USB cable. The hub uses a manifest protocol to identify itself and report which sensors are connected to each port.

This is useful when you need many sensors in a compact form factor, or when you've run out of I2C addresses on the Pi's built-in bus (since each hub port is an independent I2C bus via a TCA9548A multiplexer).

How It Works

  1. Plug in the hub — Connect the USB sensor hub to any available USB port on your Pi.
  2. Peripheral scan detects it — The Pi's peripheral scan automatically detects the hub on its serial port (typically /dev/ttyACM0).
  3. Manifest protocol — The hub sends a JSON manifest describing its firmware version and each port's connected sensor (matched to parts library IDs).
  4. Sensors appear in the Configurator — Detected sensors show up in the Discovered Devices panel, ready to add to your configuration.

Sensor Port Independence

Each port on the hub operates as an independent I2C bus through a TCA9548A I2C multiplexer chip. This eliminates I2C address conflicts — you can connect multiple sensors that share the same I2C address (for example, three BME280 sensors at 0x76) by placing each on a different hub port.

Adding Hub Sensors to Your Configuration

After the peripheral scan detects a USB hub:

  1. Open the Configurator and start or edit a draft.
  2. In the parts picker, hub-detected sensors appear with a USB icon and their port number.
  3. Add them like any other sensor — they appear in your parts list with their hub port noted.
  4. Configure and wire them normally. The flow generator handles the hub's port routing automatically.

Troubleshooting

Hub not detected after plugging in:

  • Run a new peripheral scan from the dashboard (Settings > Device > Scan Peripherals).
  • Check that the hub's USB cable is firmly seated. Try a different USB port.
  • Verify the hub firmware is compatible by checking the manifest version in the scan results.

Port shows no sensor but a sensor is connected:

  • Ensure the sensor is fully seated in the hub port's connector.
  • Some sensors require a brief warm-up period after connection. Wait 10 seconds and re-scan.

I2C address still conflicts:

  • This should not happen with hub ports (each is an independent bus). If it does, check that the hub firmware is up to date.
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