Learn about the built-in Modules

By Kevin McAleer,    3 Minutes

Picture of a honeycomb close up


MicroPython has many modules that are built into the firmware. We still need to import these if we want to use them in our code.

This is because when we import a module MicroPython has to read all the lines of code in that module and store the functions in RAM (Random Access Memory). MicroPython devices have limited RAM so we need to ensure we only import the modules we need for each specific program.

Lets have alook at all the modules on our MicroPython device.

  1. Type the following directly into the REPL:

Screenshot of all the installed Modules

A screenshot of all the installed Modules

You’ll notice that most of the modules have u as the first letter, this is because they are the simplified MicroPython version of standard Python libraries (in some cases). The u is an ascii version of the Mu or μ symbol which is the Greek letter for Micro.

A module is just another MicroPython program, one that just contains other functions. Modules tend to by collections of related functions.

Table of Built-in Modules

Below is a table of the most commonly used modules:

Module Alias Description
math cmath contains functions such as radians, sin, cos, sqrt, tan
dht - a class for use with the dht range of temperature sensors
framebuf - the Frame Buffer class - useful for creating graphics and working with displays
gc - the Garbage Collector - helps keep memory unfragmented
neopixel - a class for use with Adafruit Neopixels, or any APA102 and WS1218 RGB LED Strips
network - you’ll use this a lot if you’re working with Wi-Fi, webservers and APIs
umachine machine contains lots of board specific functions and constants
utime time you’ll use this to access the sleep function which is used in nearly all physcial computing projects, such as robotics

This isn’t an extensive list, and each variety of board may have a slightly differnt list of modules.


To investigate each module you can use the dir() function:


From the REPL type:


In the example above you’ll discover a list of all the functions, classes and Constants in the module named machine.

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