python-tm1637 0.1.2

Library for TM1637-based LED display modules

TM1637

A modern Python library for interfacing with TM1637-based 4-digit 7-segment LED display modules, using the Linux GPIO character device interface (gpiod).

Overview

The TM1637 is a driver IC commonly used in 4-digit 7-segment LED display modules. This library offers a clean, Pythonic interface for controlling these displays from any Linux-based platform with GPIO support, including Raspberry Pi, BeagleBone, and other single-board computers.

Features

• Hardware-agnostic implementation using the modern Linux GPIO character device interface
• Automatic detection of the available GPIO chip device for the given clock and data I/O lines
• Uses the official libgpiod Python bindings: gpiod v2
• Text display
• Scrolling text
• Hexadecimal display (0x0000 to 0xffff)
• Number display (-999 to 9999 or two -9 to 99)
• Temperature display (-9 to 99 with degree Celsius or -9.9 to 99.9 with degree)
• Support for decimal point displays through TM1637Decimal class

Installation

pip install python-tm1637

Requirements

• Python 3.9 or later
• gpiod 2.3.0 or later
• Linux-based system with GPIO pins

Hardware Connections

TM1637	Pin
CLK	GPIO X
DIO	GPIO Y
VCC	3.3V or 5V
GND	Ground

where TM1637(clk=X, dio=Y)

Quick Start

import time

import tm1637


# Initialize display connected to GPIO 23 & 24 at /dev/gpiochip4
display = tm1637.TM1637(clk=23, dio=24, chip_path="/dev/gpiochip4")

# Write segments directly
display.write([127, 127, 127, 127]) # 8888
time.sleep(1)

# Turn off all LEDs
display.write([0, 0, 0, 0])
time.sleep(1)

# Display text
display.show("HIYA")
time.sleep(1)

# Display a number
display.number(8888)
time.sleep(1)

API Reference

TM1637 Class

Constructor

TM1637(clk, dio, *, chip_path="/dev/gpiochip*", brightness=7)

• clk: GPIO pin number for the clock line
• dio: GPIO pin number for the data I/O line
• brightness: Initial brightness level (0-7, default: 7)
• chip_path: Path to the GPIO chip device (defaults to auto-detection)

Properties

• brightness: Get or set the display brightness
• chip_path: Get the path to GPIO chip device in use
• clk: Get the GPIO pin number of the clock line passed to constructor
• dio: Get the GPIO pin number of the data I/O line passed to constructor

Methods

• write(segments, pos=0): Write raw segments
• show(string, sep=False): Display a string
• scroll(string, delay=0.25): Scroll a string across the display
• hex(val): Display a hexadecimal value (0x0000 to 0xffff)
• number(num): Display an integer value (-999 to 9999)
• numbers(num1, num2, sep=True): Display two integers values (-9 to 99)
• temperature(num): Display a temperature integer value
• temperature_decimal(num): Display a temperature decimal value

Static Methods

• encode_char(char): Convert a character to its segment representation
• encode_digit(digit): Convert a digit to its segment representation
• encode_string(string): Convert a string to an array of segments

TM1637Decimal Class

Extends TM1637 to enable support for display modules having a decimal point after each digit.

Static Methods

• encode_string(string): Convert a string [with periods in-between] to an array of segments

Permissions

To access the GPIO chip device without root permissions, the user must be in the gpio group. To add the current user to the gpio group:

sudo usermod -aG gpio $USER
sudo reboot

Examples

Clock Display

import time

import tm1637


display = tm1637.TM1637(clk=23, dio=24)

colon = True
while True:
    time.sleep(1 - time.time()%1)
    lt = time.localtime()
    display.numbers(lt.tm_hour, lt.tm_min, sep=colon)
    colon = not colon

Temperature Display

import tm1637


display = tm1637.TM1637(clk=23, dio=24)

display.temperature(23) # 23*C
display.temperature_decimal(23.5) # 23:5*

Scrolling Text

import tm1637


display = tm1637.TM1637(clk=23, dio=24)

display.scroll("HELLO WORLD", delay=0.1)

License

MIT License - check the LICENSE file for details.

Sources

• Original MicroPython implementation by Mike Causer
• Python port for Raspberry Pi by Patrick Palma