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reSpeaker Flex FAQ

This page contains verified answers for the reSpeaker Flex. Each answer states the product variant and firmware mode it applies to, together with the date it was last verified against current official sources.

Before you begin​

  • Confirm the exact product variant and the firmware mode (USB or I2S) the device is running.
  • Check the current firmware version before applying version-specific steps.
  • Answers on this page were last verified on 2026-08-31; re-check the linked official sources if you are reading this later.

Documentation & Usage​

Where can I download ReSpeaker Flex 2D and 3D mechanical files?​

Applies to: Mechanical integration of a ReSpeaker Flex XVF3800 core board with a Linear-4 or Circular-4 microphone array

Last verified: 2026-09-01

Use the official Flex Resources section. It publishes DXF and STEP files for the Circular-4 array, Linear-4 array, and core board; select the geometry-specific files for the hardware being integrated.

Prerequisites:

  • The exact microphone geometry used by the design
  • DXF- and STEP-compatible CAD software
  • Physical hardware for revision and fit checks
  1. Open the Resources section of the current Flex getting-started page.
  2. Download the matching Linear-4 or Circular-4 DXF and STEP files together with the core-board files.
  3. Import the files into the CAD tool and verify mounting holes, connector positions, and array geometry against the physical units.
  4. Keep the Circular-4 and Linear-4 models separate; they are different mechanical layouts.

Success criteria:

  • The selected DXF and STEP files import successfully
  • The models match the array geometry and physical mounting and connector features used in the design

Notes:

  • The public files do not by themselves validate enclosure acoustics, manufacturing tolerances, or a custom 45-degree microphone installation.

References:

How do I verify full-duplex I2S between ReSpeaker Flex and XIAO ESP32S3?​

Applies to: ReSpeaker Flex XVF3800 Linear-4 or Circular-4 with XIAO ESP32S3 using the embedded I2S path

Last verified: 2026-09-01

Run the official Flex I2S test with the geometry-matched 16 kHz I2S firmware. The sketch opens the XIAO I2S peripheral in transmit-and-receive mode, writes a 440 Hz test signal, reads microphone samples, and prints I2S RX PASS! when the receive path passes its documented sample-count check.

Prerequisites:

  • An official 16 kHz I2S image matching the Linear-4 or Circular-4 geometry
  • Arduino IDE configured for XIAO ESP32S3
  • The dependencies required by the current official Flex I2S test
  1. Confirm that the Flex XMOS is running the official 16 kHz I2S image for the attached microphone geometry.
  2. Open the current ReSpeaker Flex with XIAO ESP32S3 I2S Test page and upload its sketch through the XIAO USB port.
  3. Open Serial Monitor at 115200 baud and let the first and optional second receive checks finish.
  4. Confirm that the test reports more than 16,000 valid samples and prints I2S RX PASS!.
  5. For an audible record-store-playback check, run the separate official 16 kHz record-and-playback example after the link test passes.

Success criteria:

  • The I2S peripheral initializes without an error
  • The official test prints I2S RX PASS!
  • The optional record-and-playback example captures and replays a short audio buffer

Notes:

  • This test validates the documented digital transmit and receive paths; it does not prove a wake-word threshold, acoustic echo-cancellation performance, or speaker-to-enclosure compatibility.
  • Do not run the 16 kHz sketch unchanged against a 48 kHz firmware profile.

References:

Connectivity & Detection​

Why does the ReSpeaker Flex control script report No device found?​

Applies to: ReSpeaker Flex XVF3800 Linear-4 and Circular-4 connected to a Windows, Linux, or macOS host for USB control

Last verified: 2026-08-31

The current official Flex Python script supports Flex USB control. No device found means its USB scan returned no device matching vendor ID 0x2886 and any optional PID filter; it does not mean that Flex is unsupported. Check the XMOS USB port, dependencies, firmware mode, and geometry-specific USB image.

Prerequisites:

  • The current python_control/xvf_host.py from the official ReSpeaker Flex repository
  • Python 3.6 or later, pyusb, and the platform's libusb support; the current script also requires libusb-package on Windows
  • A known-good USB data cable connected to the XMOS USB-C port near the RST button
  1. Connect the host to the Flex XMOS USB-C port near the RST button, not to a XIAO USB port, and confirm that the host detects a USB device.
  2. Install the dependencies documented by the Flex guide. Use python -m pip install pyusb; on Windows also install libusb-package, and on Linux or macOS ensure the system libusb library is available.
  3. Run python python_control/xvf_host.py VERSION from the current Flex repository without forcing an old PID. The current script searches VID 0x2886 across PIDs when --pid is omitted.
  4. If no device is found and the board may be running I2S or incorrect firmware, power it off, hold the Boot button, reconnect power, and confirm both DFU partitions with dfu-util -l (use sudo on Linux).
  5. Flash a current Flex USB image with dfu-util -R -e -a 1 -D /path/to/firmware.bin. Select a filename beginning respeaker_flex_usb_c for Circular-4 or respeaker_flex_usb_l for Linear-4, and select the required sample-rate/channel profile from the current official directory.
  6. After the board restarts, run the VERSION command again.

Success criteria:

  • The script prints Connected device with a ReSpeaker VID/PID
  • The VERSION command returns the Flex firmware version

Notes:

  • Do not use the obsolete conclusion that only the older XVF3800 USB product supports host control; official Flex documentation and code now provide a Flex-specific USB tool.
  • Safe Mode on Flex uses the Boot button. It supports USB DFU recovery when normal USB firmware is absent or unresponsive.
  • The current official firmware directory carries geometry-coded v1.0.3 images: c denotes Circular-4 and l denotes Linear-4. Never flash a geometry-mismatched image.

References:

Hardware Issues​

What FPC cable is documented for the ReSpeaker Flex microphone array?​

Applies to: The microphone-array connection between the ReSpeaker Flex core board and either the Linear-4 or Circular-4 array

Last verified: 2026-09-01

The official Flex guide documents a keyed 24-pin, 0.5 mm-pitch FPC interface and a 20 cm ribbon cable included with the product. Match the contact orientation and end construction as well as pin count and pitch; the public guide does not qualify a generic cable for repeated dynamic flexing.

Prerequisites:

  • The supplied cable, or a replacement whose complete mechanical contact orientation is confirmed against both connectors
  • Power removed from the Flex core board
  1. Open the locking tab on each FPC connector.
  2. Identify the exposed-contact side and the stiffener side of the cable.
  3. Insert the cable so its exposed contacts face the metal contacts inside each connector, then close both locking tabs without forcing them.
  4. Power the board and use the official capture or I2S test to verify the microphone-array connection before installing it in an enclosure.

Success criteria:

  • The cable seats fully and both locking tabs close without force
  • The connected array produces valid capture data in the selected official test

Notes:

  • The current public page does not specify contact-end thickness, same-side versus opposite-side contacts as a standalone procurement code, or a repeated-flex cycle rating.
  • Do not claim that every 24-pin, 0.5 mm-pitch cable is interchangeable or suitable for continuous movement.

References:

Tech Support & Product Discussion​

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