pyStringToSevenSegmentDisplay

A Python port of the stringToSevenSegmentDisplay Arduino library for Raspberry Pi. Drives 7-segment displays via 74HC595 shift registers using RPi.GPIO.

Requirements

• Raspberry Pi with GPIO
• RPi.GPIO

Installation

Either copy src/string_to_seven_segment_display.py into your project directory, or install via pip:

pip install git+https://github.com/neoge/pyStringToSevenSegmentDisplay.git

# upgrade (for later)
pip install --upgrade git+https://github.com/neoge/pyStringToSevenSegmentDisplay.git

On Raspberry Pi OS Bookworm and later, pip requires a virtual environment:

python3 -m venv venv  # run in your project directory
venv/bin/pip install git+https://github.com/neoge/pyStringToSevenSegmentDisplay.git
venv/bin/python your_script.py

Usage

import string_to_seven_segment_display as seg

latch_pin = 11  # Board pin numbering
clock_pin = 13
data_pin  = 12

display = seg.string_to_seven_segment_display(latch_pin, clock_pin, data_pin)
display.string_to_segments("!TEST!", auto_latch=True)

• seg.string_to_seven_segment_display(latch_pin, clock_pin, data_pin, reverse_strings=False): Creates the display driver. Set reverse_strings=True for displays that shift data from the opposite end.
• string_to_segments(input_string, auto_latch): Converts and sends the string to the display.

Supported characters: 0-9, A-Z (case-insensitive), and symbols like . , - _ = ° " ' [ ] ( ) { } / \ < > ^ : ; | ! ?.

Unknown characters default to underscore (_).

Examples

See the examples/ folder:

• seven_segment_clock.py — displays the current time, blinking the colon every second
• seven_segment_pipe.py — reads from stdin and displays each line:

  echo -n '!TEST!' | venv/bin/python seven_segment_pipe.py
  some_script.sh | venv/bin/python seven_segment_pipe.py

Autostart seven_segment_clock.py with systemd

A service template is included at examples/seven_segment_clock.service. To run the clock automatically at boot:

1. Copy the script to the target directory (e.g. /opt/segment/):

   sudo mkdir -p /opt/segment/
   sudo cp examples/seven_segment_clock.py /opt/segment/

   If the library is not installed via pip, also copy the library file:

   sudo cp src/string_to_seven_segment_display.py /opt/segment/

2. Edit the service file to match your paths and user, then install it:

   sudo cp examples/seven_segment_clock.service /etc/systemd/system/
   sudo systemctl daemon-reload
   sudo systemctl enable seven_segment_clock
   sudo systemctl start seven_segment_clock

Hardware

The matching PCB designs are available via OSHWLab or in the main repository stringToSevenSegmentDisplay (Arduino library + Gerber files).

Design	OSHWLab (open & edit live)
6x7 Segment Display (main)	Open Project
74HC595N Binary Display	Open Project
DIP Switch Serial Shift	Open Project

License

MIT License. See LICENSE file for details.