BMI055 vs BMI270: Core Differences and Selection Guide between Traditional IMU and Smart IMU

BMI270 is a highly integrated, low-power inertial measurement unit (IMU) with built-in programmable functions and motion algorithms. It combines precise acceleration and angular rate (gyroscope) measurements with intelligent on-chip motion-triggered interrupt functionality, making it more power-efficient and "intelligent" compared to traditional IMUs.

Understanding BMI270

Features

• Acceleration measurement range: ±2g / ±4g / ±8g / ±16g
• Gyroscope measurement range: ±125 / ±250 / ±500 / ±1000 / ±2000 dps
• Ultra-low power consumption: Ideal for battery-powered devices
• Built-in motion recognition algorithms
• Step counting
• Gesture recognition
• Raise-to-wake
• Activity/inactivity detection
• Interfaces: I²C / SPI
• Package: LGA, small size, easy to integrate
• Operating voltage: Low-voltage design, suitable for portable systems

Working principle

It senses three-axis acceleration and angular velocity through MEMS structures and performs some data processing and motion judgment within the chip, thereby reducing the computational load on the MCU and lowering system power consumption.

Absolute maximum ratings

What is a traditional IMU?

Compared to intelligent IMUs, traditional IMUs have simpler functions and higher controllability, but they have higher system power consumption and greater burden on the MCU. The operation of traditional IMUs generally only involves measuring raw data, does not perform complex motion algorithms within the chip, and mainly relies on the MCU or main controller to complete attitude calculation and motion recognition.

Typical examples:

1. InvenSense / TDK series:

• MPU6050 is a classic IMU entry-level model, featuring a 6-axis IMU and an I2C interface.
• MPU9250 is a 9-axis IMU with a magnetometer added, having higher accuracy and supporting SPI, often used in flight control and robotics. 

2.ST
The LSM6DS3 is a 6-axis IMU, widely used in industrial and consumer electronic products. In the early days, it was mainly used as a traditional IMU. 

3.Analog Devices
ADIS16470, a high-precision IMU, is an advanced traditional IMU with extremely strong accuracy and stability. 

4.Bosch
BMI055 is an early 6-axis IMU.

Comparison of Traditional IMU and Intelligent IMU - Using BMI055 vs BMI270 as Examples

Core Architecture Differences

1. Architecture: BMI055 is an accelerometer + gyroscope, while BMI270 is an integrated 6-axis + built-in intelligent logic
2. Data Output: BMI055 provides raw acceleration, while BMI270 provides raw data + motion events
3. Motion Algorithms: BMI055 is implemented on the MCU end, while BMI270 is executed by the sensor itself
4. MCU Load: BMI055 is high, while BMI270 is low
5. Development Cycle: BMI055 is long, while BMI270 is short

Notes: The fundamental difference between BMI055 and BMI270 is that BMI055 is a "sensor", while BMI270 is a "sensor + small motion processor".

Comparison of Working Modes 

BMI055

• Collect three-axis acceleration and three-axis angular velocity
• Send them via I²C / SPI to the MCU
• The MCU operates as follows:
• Filtering
• Attitude calculation
• Motion judgment
• The MCU determines the system behavior 

BMI270

• Collecting inertial data
• Done internally by the sensor:
• Filtering
• Activity/stationary determination
• Step/gesture recognition
• Notify MCU only when "an event" occurs

Application scenario comparison

For BMI055

1. It is commonly used in scenarios where controllability is greater than power consumption, for example: Robot
2. Industrial control
3. Posture measurement, navigation
4. A system with highly customizable algorithms

For BMI270
It is commonly used in scenarios where power consumption is more critical than performance, such as:

1. Wearables 
2. Hearables 
3. Smart clothing 
4. Augmented / virtual reality (AR/VR) 
5. Activity & Context Recognition

Advantage Comparison

• The BMI055 has completely controllable advantages and high power consumption as its disadvantages. It also has a large amount of software work.
• The BMI270 has extremely low power consumption and the MCU can enter long-term sleep mode as its advantages. However, its algorithm flexibility is not as good as that of traditional IMUs. 

Summary

The BMI055 is a typical traditional IMU, emphasizing the quality of raw data and the degree of algorithm freedom; while the BMI270, as an intelligent IMU, achieves lower system power consumption and faster product development by integrating motion processing capabilities within the chip. 

QFA

Q1: Why can BMI270 replace BMI055?
BMI055 mainly addresses the issue of "accurate measurement", while BMI270 not only provides accurate measurement but also is more power-efficient and is ready for mass production.
Q2: Is BMI055 considered obsolete by BMI270?
In the consumer and wearable technology fields, BMI270 has directly replaced BMI055 in a large number of scenarios. However, in the industrial/flight control fields, BMI055 still has irreplaceable value.