EYE on NPI: Bosch Sensortec BMI323 Inertial Measurement Unit

This week's EYE ON NPI will get you designing IMUs #LikeABosch (https://www.bosch.com/stories/like-a-bosch/) with the Bosch Sensortec BMI323 Inertial Measurement Unit (https://www.digikey.com/en/product-highlight/b/bosch-sensortec/bmi323-inertial-measurement-unit). A low cost, but high precision 6-axis inertial measurement unit (IMU) that has 16-bit accelerometer and 16-bit gyroscope for quality output at a great price. This sensor comes with two sensors combined inside: an accelerometer (https://en.wikipedia.org/wiki/Accelerometer) and a gyroscope (https://en.wikipedia.org/wiki/Gyroscope) - both MEMS sensors (https://en.wikipedia.org/wiki/MEMS). Bosch has a ton of experience with making MEMS sensors - one of our very favorite sensors is the Bosch BNO055 (https://www.digikey.com/en/products/detail/bosch-sensortec/BNO055/6136301) which has accelerometer, gyro and also magnetometer as well as a SAMD21 chip inside that runs a sensor fusion algorithm, which makes it great for projects that want to get going with full orientation data quickly. But you'll pay for that convenience: the BNO055 costs about $7.50 a hefty BOM cost. If you've already got a microcontroller on your design, say a Cortex M series or ESP32 or other fairly powerful chip with an FPU or secondary core, you can save a bundle by DIY'ing your own sensor fusion. You can even do some very basic orientation sensing with just a 6-axis sensor like this one, or if you want to also fuse in magnetometer data, the BMM150 (https://www.digikey.com/en/products/detail/bosch-sensortec/BMM150/4196671) is a great mini I2C sensor that will work with any Bosch 6-axis IMU - combine with the BMI323 and for about $3 total you can have great 9-DoF sensor. Then you can use Bosch's Sensor Fusion Software (https://www.bosch-sensortec.com/software-tools/software/sensor-fusion-software/) BSXlite which comes as binary blobs for ARM Cortex chips that take in the raw sensor values and pop out quaternion (https://en.wikipedia.org/wiki/Quaternion) and Euler angles (https://en.wikipedia.org/wiki/Euler_angles) - you could probably request for them to compile it for another chip family like Tensilica or RISC-V if you like. The BMI323 has 16-bit data out for both sensors, and FIFO's so you will get quality data without skipping a sample. There's a full datasheet that goes through every setting and register for the BMI323 but if you'd like to skip the low-level implementation part, Bosch has been great for releasing portable C code support for their chips and the BMI3 series has its own github repo (https://github.com/BoschSensortec/BMI323-Sensor-API) with just about all functionality implemented. Note it's fairly 'generic' code, with Linux Kernel headers but otherwise without HAL implementation, so you'll need to port the common.c file to your platform (https://github.com/boschsensortec/BMI323-Sensor-API/tree/main/examples/common) to read and write I2C or SPI and add chip-specific delay. If the idea of a low cost IMU has you doing the twist or shaking your arms in excitement, the Bosch Sensortec BMI323 Inertial Measurement Unit (https://www.digikey.com/short/m33tnfdn) is in stock now at Digi-Key, with thousands of pieces ready for instant purchase. Order today and Digi-Key will package and ship your shipment instantly: you'll be motion sensing #LikeABosch (https://www.bosch.com/stories/like-a-bosch/) by tomorrow afternoon.