DigiSim: Ultra-Modern Digital Logic & Schematic Circuit Simulator

DigiSim is an interactive, browser-based digital logic circuit simulator that combines manual drag-and-drop circuit creation with automated ML-based image-to-circuit detection.

Build and simulate logic circuits manually on a dark glassmorphic canvas, or upload a picture/schematic of a circuit to let DigiSim automatically detect the gates, trace the wires, and construct the interactive circuit for you.

🔬 Transistor-first workflow (Cadence-style)

DigiSim no longer ships ready-made NOT/AND/OR/NAND/NOR/XOR primitives in the palette. The base building blocks are NMOS/PMOS transistors, supplies (VDD/GND), digital inputs/outputs, and wires:

1. Place NMOS/PMOS from Transistors, add a Voltage Source (VDD), Ground, two Inputs and one Output.
2. Wire a CMOS gate (e.g. NAND: 2× PMOS in parallel to VDD, 2× NMOS in series to GND, gates to A/B, drains to Y). The switch-level solver shows the correct truth table live in the terminal panel.
3. Drag-select the gate, click Package in the selection toolbar, name it (e.g. NAND), and save it to My Library → Standard Cells.
4. Reuse the cell anywhere — including inside another cell (e.g. an AND built from a NAND cell + a NOT cell). Double-click a cell to drill down to its transistors. Cells persist in localStorage across reloads.
5. My Library is pre-seeded with transistor-built NOT, NAND, NOR plus hierarchical AND (NAND+NOT), OR (NOR+NOT), XOR (4× NAND) — open any of them to inspect down to transistors.

Legacy note: canvases saved with the old andGate/nandGate/… primitives still load, render, and simulate (hidden compatibility path), but new designs should use the seeded cells or package their own.

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⚡ Key Features

• ⚡ Glassmorphic Dark UI (v2.0 Pro): Ultra-modern, responsive dark layout (#0B0F19) with glowing status indicators, translucent navbars, and custom ReactFlow node styling.
• 🎨 Consolidated Component Library: Categorized drag-and-drop sidebar featuring transistors (NMOS/PMOS), IO controls (Toggle Switches, LED Probes, Clock Signals), Analog components, and a personal My Library of transistor-built standard cells.
• 🔍 ⌘K Component Search: Instant search and filtering across the entire component palette.
• ⚙️ Real-time Simulation Engine: Relaxation-based digital gate evaluation, a switch-level CMOS solver (NMOS/PMOS + supplies resolve to correct truth tables), and Modified Nodal Analysis (MNA) solver for analog nodes with live signal propagation (HIGH/LOW/Z/X).
• 📸 ML Image-to-Circuit Detection:
  • YOLOv8 Schematic Detection: Detects drawn logic gates and uses OpenCV line transforms (Hough) to extract wire paths into a NetworkX graph.
  • DINOv2 Physical Board Analysis: Physical board photo component recognition using DINOv2 embeddings and OCR.
• 📄 Human & LLM-Parsable Netlist JSON Schema: Export and import circuits using an intuitive, semantic JSON format (input_A.out -> and_1.a) with 100% loss-free round-trip reconstruction.

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🛠️ Tech Stack

Frontend

• Framework: React 19, TypeScript
• Canvas & Nodes: ReactFlow v11
• Styling: Tailwind CSS v4, Glassmorphism, DaisyUI v5

Backend (Image Recognition & Pipeline)

• Engine: Python 3.14, Flask, uv
• Machine Learning: Ultralytics YOLOv8, PyTorch, DINOv2, OpenCV, NetworkX

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🚀 Quick Start

1. Clone the Repository

git clone https://github.com/Mani212005/DigiSim.git
cd DigiSim

2. Run the Frontend (Port 3000)

cd frontend
npm install --legacy-peer-deps
npm start

Open http://localhost:3000 in your browser.

3. Run the Backend (Port 5001)

cd backend
uv sync
uv run python app.py

4. Model Context Protocol (MCP) Server Setup

See DigiSim Model Context Protocol (MCP) Server below for setup instructions and tool capabilities.

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🔌 DigiSim Model Context Protocol (MCP) Server

DigiSim includes a stdio Model Context Protocol (MCP) server allowing AI agents (like Claude Desktop, Antigravity, and Cursor) to generate circuits, run MNA simulations, detect breadboard/schematic photos, and export SPICE netlists.

Available MCP Tools

• digisim_create_circuit: JSON netlist to schematic generator.
• digisim_simulate_mna: Execute MNA / SPICE simulation and return node voltages & waveforms.
• digisim_detect_circuit_photo: Run YOLO detection on base64 image input.
• digisim_export_spice: Generate SPICE netlist text from canvas JSON.

Registration Instructions

To register DigiSim's MCP server with Claude Desktop or Antigravity, add the following to your claude_desktop_config.json or MCP settings:

{
  "mcpServers": {
    "digisim": {
      "command": "uv",
      "args": [
        "run",
        "--directory",
        "/absolute/path/to/DigiSim/backend",
        "python",
        "mcp_server.py"
      ]
    }
  }
}

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🌐 Hosting

Live topology: static frontend on Vercel, Flask backend as a Docker container on Render (API calls proxy through vercel.json rewrites). Click-through deploy steps and required secrets: docs/deploy-vercel-render.md.

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📄 License

Distributed under the MIT License. See LICENSE for details.