BHI385 Smart IMU - Hardware details

Pinout

Pin details

Pin Marking	Pin Name	Description
INT	Interrupt	Active interrupt output from the BHI385 HIRQ pin (3.3V logic)
GND	Ground	Common ground for power and signals
3V3	Power	3.3V supply input
SCL	Clock	I2C clock line (3.3V level, level-shifted to 1.8V on board)
SDA	Data	I2C data line (3.3V level, level-shifted to 1.8V on board)

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This board operates from a 3.3V supply. An onboard regulator generates the 1.8V rail required by the BHI385, and a dual NMOS level-shifter translates I2C signals between the 1.8V sensor domain and the 3.3V host interface. The board is not directly 5V-tolerant on the I2C lines without an external level-shifter.

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Qwiic (formerly easyC)

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This board is fully Qwiic-compatible! Just plug it into your board using a Qwiic/easyC/STEMMA QT cable and start coding!

Qwiic (formerly easyC) details and specifications

Learn about hardware specifications, compatibility, and usage of the Qwiic connector.

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Dimensions

• Board Dimensions: 22 × 22 mm (0.87 × 0.87 in)
• Header Pin Holes: 1.5 mm
• Screw Holes: Designed for M3 screws (3.2 mm diameter)
• Soldered boards are LEGO compatible! 🧱

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Jumper Details

This board contains hardware jumpers; see below for their locations and functions:

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Jumper	Default State	Function
JP1	NC (Normally closed)	Connects the 3.3V-side pull-up resistors (both SDA and SCL) on the I2C level-shifter to the 3V3 rail.
JP2	NC (Normally closed)	Connects the 1.8V-side pull-up resistors (both SDA and SCL) on the I2C level-shifter to the 1.8V rail.
JP3	NO (Normally open)	Connects the 3.3V rail to the input of the onboard LDO regulator. Bridge to power the LDO from 3V3; leave open to isolate the regulator input.
JP4	NC (Normally closed)	Connects the EN pin of the onboard regulator to the 3.3V rail, enabling the regulator.
JP5	0x29	Selects the I2C address: bridge towards 0x29 (HSDO = VDDIO, default) or 0x28 (HSDO = GND).

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Hardware repository

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The hardware repository for this board is not available yet! We're working on it. In the meantime, please contact us to receive the hardware files.

The hardware repository contains everything you need to understand, modify, or manufacture the board. The different output folders are versioned. You can check which board version you have specifically by finding the version mark on the PCB.

Below is an overview of the available files.

CAD files

We use KiCad, an open-source PCB design tool. You can open and edit the .kicad_pro project file, which includes both the schematic and PCB layout.

The PANEL files are used internally for production.

Schematic

The OUTPUTS folder contains the schematic in .pdf format, exported from KiCad.

BOM (Bill of Materials)

The bill of materials (BOM) is provided in two formats:

• A standard .csv table, listing all components, part numbers, and values.
• An interactive BOM (.html) that visually highlights each component on the PCB, making it easy to locate and reference parts.

3D files

A 3D model of the PCB is available in .step format, allowing you to inspect the board design in CAD software.

Gerber files

Gerber files are essential for PCB manufacturing. The repository includes copper layers, solder mask, silkscreen, paste layers, drill files, board outline, and the Gerber job file.

Compliance

The Compliance section includes CE, UKCA, Safety Instructions, and an Info.txt file.