TU Darmstadt — Measurement and Sensor Technology (MUST)

Made by MUST Python License: MIT Platforms

Cross-platform Python library to read a Resense HEX32 6-axis Force/Torque sensor via USB.

The Resense evaluation box enumerates as a USB CDC-ACM serial device, so the library opens it with pyserial (raw, 8-N-1, 2 Mbaud) and reads the same 28-byte binary frames as our C++ and Arduino libraries. The API mirrors those libraries.

Please note that this is an unofficial library and that we are not affiliated with the Resense company. It is provided as-is under the MIT license and follows the public serial protocol used by our (likewise unofficial) Arduino library. "Resense" and "HEX" are trademarks of their respective owner.

pip install . # from a clone of this repo
# or, for development:
pip install -e .

This pulls in pyserial and installs a hex32-read command-line tool.

from resensehex import ResenseHEX
with ResenseHEX("/dev/ttyACM0") as hex: # or "COM7" on Windows
 hex.align() # find the frame boundary (continuous mode)
 for _ in range(5):
 f = hex.read_frame_and_timestamp()
 print(f"Fz={f.fz:.3f} N T={f.temperature:.2f} C")

Command-line tool:

hex32-read --quiet # prints achieved rate once per second (~1 kHz)
hex32-read --quiet --csv run.csv # log the stream to CSV
hex32-read COM7 --quiet # Windows: pass the COM port
hex32-read --tare # zero the sensor over USB (or use the hardware button)

In continuous mode the sensor streams frames with no header byte, so the reader aligns to a frame boundary once (align()). In trigger mode each SAMPLE is answered by exactly one frame, so it self-aligns.

The output rate of continuous mode is set on the sensor (config buttons on the electronics, e.g. 1 kHz); it is not changed over USB.

On Linux, the user must be in the dialout group:

sudo usermod -aG dialout $USER # then re-login

The HEX32 evaluation electronics is configured with the on-board buttons/switch — not over USB. For this library you want interface = USB (3) and a continuous sampling rate (5); zeroing is the Tara button (1).

Resense HEX32 evaluation box controls

For continuous reading with this library, set (3) → USB and (5) → 1 kHz (or 500/100 Hz). Trigger mode on (5) pairs with trigger_and_read(). The internal RP2040 is why the box enumerates as a generic USB-serial device (VID 2E8A) on Windows.

Image and settings table from our Arduino library (MIT).

ResenseHEX(device, baud=2_000_000, *, read_timeout=0.3, tare_timeout=20.0) — also a context manager.

HexFrame is a dataclass with fx fy fz mx my mz temperature timestamp (forces N, torques mNm, temp °C, timestamp = host time.monotonic() seconds).

• Frames are little-endian float32; decoding is a single struct.unpack("<7f", ...).
• The sensor enumerates as a full-speed USB device. If it drops off the bus (Linux dmesg shows error -110 / -62, the device node disappears), that's a power/cable issue — use a powered USB hub and a good cable.
• Taring over USB works, but on a cold / just-reconnected sensor the first TARA may have no effect; let it warm up and retry, or use the hardware button.

• C++ / USB: TUDA-MUST/ResenseHEX-cpp (Linux/macOS/Windows, same API)
• Arduino / UART: TUDA-MUST/ResenseHEX

Independent Python/USB port of the protocol from TUDA-MUST/ResenseHEX (Arduino, MIT). MIT licensed — see LICENSE.

This is an unofficial project and is not affiliated with, authorized, or endorsed by Resense. All trademarks belong to their respective owners.