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Instructions for using the BSEC Arduino Library in Arduino 1.8.13

About BSEC

Bosch Sensortec Environmental Cluster (BSEC) Software v1.4.8.0 released on July 8th, 2020

The BSEC fusion library has been conceptualized to provide a higher-level signal processing and fusion for the BME680. The library receives compensated sensor values from the sensor API. It processes the BME680 signals to provide the requested sensor outputs.

Key features

  • Precise calculation of ambient air temperature outside the device
  • Precise calculation of ambient relative humidity outside the device
  • Precise calculation of pressure outside the device
  • Precise calculation of air quality (IAQ) level outside the device

Typical applications

  • Health monitoring/ well-being (warning regarding dehydration / heat stroke)
  • Home automation control
  • Control heating, venting, air conditioning (HVAC) applications
  • Gaming applications like flying toys
  • Internet of things applications
  • Context awareness
  • Enhancement of GPS navigation (e.g., time-to-first-fix improvement, dead-reckoning, slope detection)
  • Indoor navigation (floor detection, elevator detection)
  • Outdoor navigation,
  • Leisure and sports applications
  • Weather forecast
  • Health care applications (e.g. Spirometry)
  • Vertical velocity indication (e.g. rise/sink speed)

Supported platforms

  • BSEC library is supported on 32, 16 and 8 bit MCU platforms

Available binaries for download:

Platform Compiler ROM (BSEC) ROM (BSEC lite*) RAM TYPE
Cortex-ARM ARMCC 19-20k 12-13k 1k Cortex-M0, M0+, M3, M4, M4_FPU, M7
Cortex-ARM GCC 20-22k 12-14k 1k Cortex-M0, M0+, M3, M4, M4_FPU, M7
Cortex-ARM IAR 20k 12-13k 1k Cortex-M0, M0+, M3, M4, M4_FPU, M7
Cortex-A* GCC 21k 13k 1k Cortex-A7
AVR_8bit AVR-GCC 42k 25 1k MegaAVR, XMEGA
AVR_32bit AVR-GCC 24k 13k 1k 32-bit AVR UC3
ESP8266 xtensa-lx106-elf-gcc 28k 17k 1k ESP8266
ESP32 xtensa-esp32-elf-gcc 24k 14k 1k ESP32
MSP430 msp430-elf-gcc 34k 20k 1k MSP430
Android system-x86 gcc 39-49k 22-26k 1k x86, x86_64
Android system-arm gcc 21-38k 13-19k 1k arm, arm64
Raspberry PI 0 linux arm-linux-gnueabihf-gcc 71k 56k 1k armv6-32bits
Raspberry PI3 linux arm-linux-gnueabihf-gcc 72k 57k 1k armv8-a-64bits

The library size information above doesn't include additional dependencies based on the embedded system project & platform.

*The BSEC lite version is an abbreviated version of BSEC with reduced code size & memory requirements. It does not include functions to save the state of BSEC, if the device powers down.

For other platforms, please contact your local Bosch Sensortec representative


  • Easy to integrate
  • Hardware and software co-design for optimal performance
  • Complete software fusion solution out of one hand
  • Eliminates need for own fusion software development
  • Robust virtual sensor outputs optimized for the application

Software license agreement

The BSEC software is only available for download or use after accepting the software license agreement. By using this library, you have agreed to the terms of the license agreement.

BSEC license agreement

Installation and getting started

1. Install the latest Arduino IDE

As of this publication, the latest Arduino IDE 1.8.13 can be downloaded from this link

2. Install the BSEC library

Either download this library as a zip and import it into the Arduino IDE. Refer to this guide on how to import libraries.

3. Modify the platform.txt file

If you have already used the previous example code and hack guide, remove the linker flag -libalgobsec in the platform.txt file and reference to the compiler.c.elf.extra_flags.

The standard arduino-builder now passes the linker flags under compiler.libraries.ldflags. Most platform.txt files do not already include this new optional variable. You will hence need to declare this variable's default and add it to the end of the combine recipe. It is recommended to declare it in the following section like below,

# These can be overridden in platform.local.txt

and add it in the combine recipe like the below examples

ESP8266 community forum's ESP8266 core

Original line 105,

## Combine gc-sections, archives, and objects
recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {build.exception_flags} -Wl,-Map "-Wl,{build.path}/{build.project_name}.map" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{archive_file_path}" {compiler.c.elf.libs} -Wl,--end-group  "-L{build.path}"

should become

## Combine gc-sections, archives, and objects
recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" {build.exception_flags} -Wl,-Map "-Wl,{build.path}/{build.project_name}.map" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{archive_file_path}" {compiler.c.elf.libs} {compiler.libraries.ldflags} -Wl,--end-group  "-L{build.path}"

Arduino's SAMD core

Original line 96,

## Combine gc-sections, archives, and objects
recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}"  "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} "-T{build.variant.path}/{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" --specs=nano.specs --specs=nosys.specs {compiler.ldflags} -o "{build.path}/{build.project_name}.elf" {object_files} -Wl,--start-group {compiler.arm.cmsis.ldflags} -lm "{build.path}/{archive_file}" -Wl,--end-group

Should be,

recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}"  "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} "-T{build.variant.path}/{build.ldscript}" "-Wl,-Map,{build.path}/{build.project_name}.map" --specs=nano.specs --specs=nosys.specs {compiler.ldflags} -o "{build.path}/{build.project_name}.elf" {object_files} -Wl,--start-group {compiler.arm.cmsis.ldflags} -lm "{build.path}/{archive_file}" {compiler.libraries.ldflags} -Wl,--end-group

4. Verify and upload the example code

Start or restart the Arduino IDE. Open the example code found under File>Examples>Bsec software library>Basic.

Select your board and COM port. Upload the example. Open the Serial monitor. You should see an output on the terminal.

Note that not all supported cores have been tested. In such cases, the examples can be found under File>Examples>INCOMPATIBLE>Bsec software library>Basic

5. Tested board/core list

The current list of tested boards include,

Core MCU Tested boards Arduino core version Arduino core repository
Atmega 2560 Arduino MEGA 2560 Shipped with Arduino 1.8.13 Shipped with Arduino 1.8.13
Cortex-m0+ Arduino Zero Upstream of v1.6.21 SHA-1 hash 86081cbf35fc0df0612a1b2c054877ff6788f9e7
Cortex-m3 Arduino Due SHA-1 hash 0a4c3b196a02e48e31b752a05d8c8064007874dc
Cortex-m4 with FPU Adafruit BlueFruit NRF52 Feather Upstream of v0.10.1 SHA-1 hash 11614dae701a35f905d09792c7388d648b125369
Esp32 Sparkfun ESP32 Thing v1.0.3-rc1
Esp8266 Adafruit Feather HUZZAH Upstream of v2.5.1 SHA-1 hash 625c3a62c4991347e8298fb5e4021bc6f6df7099

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