Logisim is a circuit simulator, originally available here.

Carl Burch, the original author of Logisim, abandoned development in 2011 and moved on to a similar successor project, Toves in 2013, because Logisim's code base is in need of a major overhaul. Rather than start from scratch (something you should never do), this fork of Logisim picks up where Dr. Burch left off to incrementally improve Logisim.

Logisim's code itself has numerous smells. Here's an incomplete list of these:

• No test suite!
• Undocumented packages, classes, methods
• Duplicated and dead code
• No coherent organization (it should be MVC)
• High coupling, low cohesion (it would benefit from IoC)
• Unnecessarily reimplements functionality found in standard or third party libraries (e.g., it has it's own Toolbar classes)
• Code to draw components is too low-level

Logisim's user interface has numerous gotchas that need to be addressed. Here's some of the more important issues:

• The file format is not merge-friendly, making it impossible for students to collaborate on circuits
• Unreasonable defaults
• Limited interaction styles
• Single (graphical) view of circuit

It is arguably the best free/libre and gratis tool for teaching circuit design. That is why its development must continue.

If you just want to test the newest developer version to report issues or for new features, download it here. Download

The build script recognizes the following commands:

./gradlew build     # Build application jar
./gradlew eclipse   # Build Eclipse configuration
./gradlew createExe # Build logisim executable
./gradlew run       # Run logisim from gradle
./gradlew sonar     # Examine problems using Sonar

To build the executable for Windows, you must install launch4j and ensure it is in the system path or you could install launch4j just into the root of the project (build process will find it and it will be ignore by git).

To examine problems with Sonar, you need to download SonarQube (the server) first into a folder without spaces in it. Then, run SonarQube for your platform and run gradlew sonar and go to Sonar's page. See the status of what everybody's working on using the Logisim Trello Board.