SparkFun
9DoF IMU Breakout - IM19
· MPN: SEN-30381
This breakout pairs the Feyman (FMI) IM19 9DoF IMU with a board layout made for high-accuracy PNT and RTK GNSS projects. It combines MEMS sensor data with ex...
This breakout pairs the Feyman (FMI) IM19 9DoF IMU with a board layout made for high-accuracy PNT and RTK GNSS projects. It combines MEMS sensor data with external GNSS RTK positioning information to provide precise attitude measurements and tilt compensation for survey-style workflows.
The IM19 is used in SparkPNT’s professional GNSS Flex and FP Surveyor products, supporting tilt-compensated surveying and continuous Dead Reckoning navigation. It is designed to work exclusively with RTK GNSS receivers and requires GNSS positioning data with an active “RTK Fix” status in its NMEA message; it will not operate with standard non-RTK GNSS receivers or positions such as “RTK float”, “DGPS”/“DGNSS” or “3D fix”.
To get started, feed the board NMEA GGA, GST and RMC messages at 5Hz, plus a standard Pulse-Per-Second timing signal. It outputs a proprietary NMEA ASCII GPFMI message containing the compensated position of the survey pole tip, plus Roll, Pitch and Yaw from the IMU.
The hardware is set up for flexible integration, with three UART interfaces, USB-UART access for UART1 and UART2, a locking JST connector for UART3, breadboard-compatible pads, multiple power options and a PCB footprint that matches SparkFun’s standard RTK GNSS boards for easy stacking.
Features:
- Survey-Grade Accuracy: Delivers roll and pitch measurements accurate to within 0.05 degrees.
- Tilt Compensation: Calculates a virtual digital level point at any tilt angle to reduce the need for perfectly vertical survey poles.
- Dependable Sensor Fusion: Provides continuous navigation (Dead Reckoning) even during brief GNSS signal loss.
- IM19 Inertial Measurement Unit: Built around the Feyman (FMI) IM19 IMU.
- UART support: Supports three UART interfaces.
- USB connectivity: USB connectivity via a dual-channel CH342 interface for UART1 and UART2.
- Locking JST Connection: UART3 is routed to a secure, 4-pin locking JST connector.
- Breadboard Prototyping: All three UARTs are broken out to standard pads.
- CH342 isolation: Pull the CH342_EN pad low to isolate the CH342 for direct access to UART1 and UART2.
- Stackable layout: PCB matches the footprint of standard RTK GNSS boards.
- Centred IMU placement: IM19 chip is placed exactly at the centre of the board to simplify LEVER_ARM calculations.
- PWR LED indicator: Onboard power LED indicator.
- ESD protection: Includes ESD protection.
Specifications:
- IMU: IM19 Inertial Measurement Unit
- UART interfaces: three
- USB-UART interface: dual-channel CH342 interface (UART1 & 2)
- JST connector: 4-pin locking JST connector (UART3)
- Power input: USB
- Power input: VIN (5V nominal)
- Power input: JST Pin 1 (default 3.3V; can be configured for 5V)
- Power input: 3.3V
- Breakout pad: UART (x3)
- Breakout pad: PPS signal input (required)
- Breakout pad: BOOT (for firmware upgrade)
- Breakout pad: RESET
- Breakout pad: GPIO (for external beeper)
- Breakout pad: CH342 EN (pull low to isolate the CH342)
- Breakout pad: MEAS jumper for current measurement
- Accelerometer operating range: ±8g
- Gyroscope operating range: ±1000°/s
- Accelerometer Bias: ±5mg
- Gyroscope Bias Accuracy: ±0.2°/s
- Roll/Pitch: ±0.025° (1σ)
- Heading: ±0.25° (1σ)
- RTK: + 0.3mm/tilt°, with 200cm straight pole (1σ)
- Auto Steering Yaw: 0.25° (1σ)
- Initialization: ~1s
- Required NMEA messages: GGA, GST, and RMC messages at 5Hz
- Required timing signal: Pulse-Per-Second (PPS)
- Output message: proprietary NMEA ASCII GPFMI
- PCB dimensions: 1.7-inch x 1.7-inch
- IM19 Z-origin: 1.6mm above the top surface (inside the package)
- IM19 Z-origin: 3.2mm above the bottom surface
Best suited to advanced RTK GNSS integrations, field surveying equipment and navigation projects that need tilt compensation and attitude data from a compact UART-enabled breakout.
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- ESD protection
- ESD protection helps protect electronics from damage caused by static electricity discharges. It is useful on development boards because cables, sensors and modules are often plugged and unplugged during prototyping.
- GNSS
- GNSS stands for Global Navigation Satellite System, covering positioning systems such as GPS and similar satellite networks. It matters here because high-precision GNSS modules can output lots of serial position data that this product can send wirelessly to a computer or phone.
- GPIO
- General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.
- Gyroscope
- A gyroscope measures rotation, such as how fast a board is turning around its X, Y, and Z axes. This matters for projects like gesture controls, balancing robots, and motion tracking where tilt or rotation changes need to be detected.
- IMU
- An Inertial Measurement Unit combines motion sensors to measure movement and orientation. It matters for asset tracking because it can detect movement, tilt, vibration, or changes in direction.
- LED
- A light-emitting diode is a small electronic component that lights up when current flows through it in the correct direction. In this kit, LEDs create the flashing effect, so polarity and correct soldering matter for the project to work.
- PCB
- A printed circuit board is a rigid board with copper tracks that connect electronic parts without loose wires. For this kit, the PCBs also form the airplane shape, so they are both the circuit base and part of the finished model.
- RTK
- Real-Time Kinematic positioning is a GNSS technique that uses correction data from a base station to greatly improve location accuracy. It matters if you need centimetre-level positioning for robotics, mapping, surveying, or tracking rather than ordinary metre-level GPS accuracy.
- UART
- UART is a simple serial connection that sends data over separate transmit and receive wires, often labelled TX and RX. It matters because this module is designed to replace a wired UART cable with a wireless link while keeping the same serial data format.
IM19 IMU Breakout Schematic
Schematic · 365.8 KB · Click any page to view full size
IM19 IMU Tilt Sensor Integration Guide
User Guide · 387.2 KB · Click any page to view full size
Supplier page — sparkfun.com
Supplier Description · 1.2 MB · Click any page to view full size
