MicroPython libraries


Important summary of this section

  • MicroPython provides built-in modules that mirror the functionality of the Python standard library (e.g. os, time), as well as MicroPython-specific modules (e.g. bluetooth, machine).

  • Most standard library modules implement a subset of the functionality of the equivalent Python module, and in a few cases provide some MicroPython-specific extensions (e.g. array, os)

  • Due to resource constraints or other limitations, some ports or firmware versions may not include all the functionality documented here.

  • To allow for extensibility, the built-in modules can be extended from Python code loaded onto the device.

This chapter describes modules (function and class libraries) which are built into MicroPython. This documentation in general aspires to describe all modules and functions/classes which are implemented in the MicroPython project. However, MicroPython is highly configurable, and each port to a particular board/embedded system may include only a subset of the available MicroPython libraries.

With that in mind, please be warned that some functions/classes in a module (or even the entire module) described in this documentation may be unavailable in a particular build of MicroPython on a particular system. The best place to find general information of the availability/non-availability of a particular feature is the “General Information” section which contains information pertaining to a specific MicroPython port.

On some ports you are able to discover the available, built-in libraries that can be imported by entering the following at the REPL:


Beyond the built-in libraries described in this documentation, many more modules from the Python standard library, as well as further MicroPython extensions to it, can be found in micropython-lib.

Python standard libraries and micro-libraries

The following standard Python libraries have been “micro-ified” to fit in with the philosophy of MicroPython. They provide the core functionality of that module and are intended to be a drop-in replacement for the standard Python library.

MicroPython-specific libraries

Functionality specific to the MicroPython implementation is available in the following libraries.

Libraries specific to the OpenMV Cam

The following libraries are specific to the OpenMV Cam.

Third-party libraries on the OpenMV Cam

The following third-party libraries are built-in to your OpenMV Cam’s firmware:

ulabnumpy-like array manipulation library

pidProportional/Integral/Derivative Control

bno055IMU Driver

Examples scripts are located in OpenMV IDE under the IMU Shield examples folder.

ssd1306OLED Driver

tb6612Stepper Motor Driver

Examples scripts are located in OpenMV IDE under the Motor Shield examples folder.

lsm6dsoxlsm6dsox Driver

modbusmodbus protocol library

Examples scripts are located in OpenMV IDE under the Modbus examples folder.

mqttmqtt protocol library

Examples scripts are located in OpenMV IDE under the WiFi Shield examples folder.

vl53l1xToF Distance Sensor Driver

Examples scripts are located in OpenMV IDE under the Distance Shield examples folder.

Extending built-in libraries from Python

In most cases, the above modules are actually named umodule rather than module, but MicroPython will alias any module prefixed with a u to the non-u version. However a file (or frozen module) named module.py will take precedence over this alias.

This allows the user to provide an extended implementation of a built-in library (perhaps to provide additional CPython compatibility). The user-provided module (in module.py) can still use the built-in functionality by importing umodule directly. This is used extensively in micropython-lib. See Package management for more information.

This applies to both the Python standard libraries (e.g. os, time, etc), but also the MicroPython libraries too (e.g. machine, bluetooth, etc). The main exception is the port-specific libraries (pyb, esp, etc).

Other than when you specifically want to force the use of the built-in module, we recommend always using import module rather than import umodule.