CircuitSim — A Minecraft Circuit Simulation Mod

This mod was built entirely with AI assistance.

CircuitSim is a Minecraft Forge mod for version 1.20.1 that lets you build and simulate real electronic circuits inside the game. Place component blocks in the world, connect them with wires, and right-click the Simulate Block to run a full SPICE simulation powered by ngspice.

Features

Passive & basic components

• Resistor, Capacitor, Inductor
• Voltage sources: DC, sinusoidal (SIN), pulse (PULSE)
• Current source
• Diode
• Wire and Ground

Controlled (dependent) sources

• VCVS — voltage-controlled voltage source (E)
• VCCS — voltage-controlled current source (G)
• CCVS — current-controlled voltage source (H)
• CCCS — current-controlled current source (F)

IC / PDK components

• IC Resistor, IC Capacitor
• IC NMOS4, IC PMOS4 (4-terminal MOSFETs)
• SKY130A PDK support with .lib path configuration, plus a generic placeholder PDK and a free-form .include mode for custom libraries

Multi-cell blocks

• Amplifier — 5×5 op-amp subcircuit with selectable 5-pin or 7-pin (offset-null) variants and a vertical-mirror toggle for swapping inverting/non-inverting inputs and supply rails

Measurement

• Voltage Probe — labelled, measures node voltage
• Current Probe — placed in series to measure branch current

Simulation control

• Simulate Block — runs the analysis. Supported types:
  • .OP — DC operating point
  • .AC — frequency sweep (start/stop/points-per-decade, log-frequency axis)
  • .TRAN — transient analysis (time step, stop time)
  • Temperature — single value (e.g. 27) or sweep spec (e.g. 20:40:5 or 20,30,40) for one run per temperature
  • ngspice compat modes: hsa, psa, lt, ki, va
  • Parametric Block — sweeps a target component's parameter (value, W, L, mult, nf) across runs
  • Commands Block — multi-line block of raw ngspice commands injected verbatim into the netlist .control section
  • Sim Link Block — bridges two physically-disconnected sub-circuits into the same netlist without unioning their nodes (useful for routing a CCVS/CCCS controlling source from a remote region)

Output

• Graph screen — plot up to two probes simultaneously (stacked), with hover tooltips showing exact values; log10 X axis for AC sweeps
• SPICE simulation via ngspice as a subprocess — real node voltages and branch currents
• .OP results printed to the in-game chat
• In-game GUI for every component to configure values with SI-suffix parsing (p, n, u, m, k, M, …)

Requirements

• Minecraft 1.20.1
• Minecraft Forge 47.3.0
• Java 17
• ngspice installed and available on your system PATH

Installation

Method 1: Just take it

1. Install Java 17 and Minecraft Forge 47.3.0 for Minecraft 1.20.1.
2. Install ngspice and make sure ngspice_con (Windows) or ngspice (Linux/Mac) is accessible from your terminal.
3. Grab the Latest Release
4. Put the mod into your Minecraft mods/ folder

Method 2: Build it yourself

1. Install Java 17 and Minecraft Forge 47.3.0 for Minecraft 1.20.1.
2. Install ngspice and make sure ngspice_con (Windows) or ngspice (Linux/Mac) is accessible from your terminal.
3. Clone this repository:

   git clone https://github.com/Dank0v/circuitsim.git
   cd circuitsim
   

4. Build the mod using the Gradle wrapper:

   # Windows
   gradlew.bat build
   
   # Linux / Mac
   ./gradlew build
   

5. Find the compiled .jar in build/libs/ — it will be named something like circuitsim-x.x.x.jar.
6. Drop that .jar into your Minecraft mods/ folder.
7. Launch the game.

How to Use

1. Open the Circuit Simulator creative tab to find all blocks.
2. Place component blocks and connect them with Wire blocks. Every circuit needs at least one Ground block.
3. Right-click any component to open its configuration GUI and set its value.
4. Place a Simulate Block anywhere connected to the circuit.
5. Right-click the Simulate Block to run the simulation. Results appear in chat.

Probes

• Voltage Probe — place adjacent to a wire node. Right-click to give it a label. The simulation will report the voltage at that node.
• Current Probe — place in series (between two wires) to measure current through that branch.

Known Issues / TODO

License

GPL-3.0 — see LICENSE.