GitHub Heartbeat

An artistic project that creates an ECG (electrocardiogram) heartbeat pattern on GitHub's contribution graph.

What is this?

This project manipulates GitHub's contribution graph to display a realistic ECG heartbeat pattern over the course of a year. By creating backdated commits with carefully calculated frequencies, the contribution graph shows three distinct heartbeats with proper ECG characteristics: P-waves, QRS complexes, T-waves, and recovery periods.

How it works

GitHub's contribution graph displays weekly aggregates of commits, not daily values. Understanding this was crucial to creating the pattern.

The Pattern

The script creates a repeating 18-week (126-day) cycle with the following structure:

• Baseline weeks (9 weeks): 1 commit spread across the week = ~1 commit/week on the graph
• P-wave week: 7 commits (1 per day) = ~7 commits/week (small bump before heartbeat)
• Baseline week: 1 commit
• Dip week: 2 commits = ~2 commits/week (slight dip before spike)
• Spike week: 15 commits on one day = ~15 commits/week (the QRS complex - main heartbeat!)
• Recovery week: 0 commits = flat line after heartbeat
• Return to baseline (4 weeks): 1 commit/week

This pattern repeats ~3 times across a year, creating three distinct heartbeats.

Implementation

The generate_heartbeat.py script:

1. Defines the daily commit pattern for one 126-day cycle
2. Repeats the pattern across the past year
3. Creates empty backdated commits using git commit --allow-empty --date
4. Sets both author and committer dates to ensure GitHub recognizes the backdated commits

Key Insights

• GitHub aggregates contributions by week, not by day
• Empty commits are sufficient to create the pattern
• Both --date (author date) and GIT_COMMITTER_DATE (committer date) must be set
• The pattern must account for weekly totals, not daily commit counts

Usage

python3 generate_heartbeat.py

The script will:

• Generate commits for the past 365 days
• Show you the pattern and total commit count
• Ask for confirmation before creating commits
• Create all commits with proper backdating
• Provide instructions for pushing to GitHub

Warning: This rewrites git history. Use git push --force to update the remote repository.

Technical Details

• Total commits: ~112 per year (plus 1 for project files)
• Cycle length: 126 days (18 weeks)
• Heartbeats per year: 3
• Spike intensity: 15 commits/week
• Baseline intensity: 1 commit/week

Why?

An exploration of GitHub's contribution graph mechanics and a creative exercise in data visualization through commit manipulation.

License

GNU Affero General Public License v3.0