UD5 Toolkit
Bear Bag Hanging Simulator – Online PCT Method Practice
Step‑by‑step interactive animation for the PCT bear bag hanging method. Practice the throw and tie before you go.
Tag: Simulator - Virtual Testing
42+ toolsSunrise Alarm Simulator – Online Gradual Light Wake‑Up
Set a wake-up time and the screen gradually brightens from dark to warm yellow. Use as a gentle alarm.
Paper Snowflake Simulator - Online Fold & Cut Preview
Virtually fold a digital paper and cut out shapes to see a snowflake unfold. Experiment with designs before real scissors. Pure creative fun.
Two‑Pass Assembler Simulator - Online Simple SIC/XE
Write a simple assembly program and see the pass‑1 and pass‑2 symbol tables and object code. Systems programming helper.
Viewport Meta Tag Simulator - Online Test Mobile Rendering
Change the viewport meta tag and see how a page would render at different device widths. Understand responsive basics.
Print Contrast Simulator - Online See How It Looks on Paper
Upload an image and see a rough simulation of how it might look when printed. Highlights areas that may lose detail.
Browser Console Simulator - Online Practice JavaScript Logging
Type JavaScript expressions and see output like a real browser console. Supports console.log, error, warn. Use for quick testing without DevTools.
Gradient Color Blindness Simulator - Online Test Palettes
Upload a gradient or enter a palette and simulate how it appears with different types of color vision deficiency. Ensure inclusive data visualization.
Banker's Algorithm Simulator - Online Deadlock Avoidance
Set up resources and processes and run the Banker's algorithm to check for safe states. Classic OS deadlock avoidance demo.
CPU Scheduler Simulator - Online FCFS, SJF, Round‑Robin
Enter processes and see how different scheduling algorithms handle them. Gantt chart generation. OS course helper.
Screen Reader Text Simulator - Online See What It Says
Enter an HTML snippet and see a rough transcription of what a screen reader might announce. Check alt texts.
Adaptive Bitrate Streaming Simulator - Online HLS/DASH Demo
Simulate adaptive bitrate logic by switching between different quality video segments. See how ABR algorithms work.
Simple Circuit Simulator – Online Visual Resistor LED
Drag a battery, resistor, LED onto a grid and simulate current flow. Show Ohm's law in action.
Exposure Triangle Simulator – Online ISO, Aperture, Shutter
Adjust ISO, f‑stop, shutter speed and see a simulated image brightness and depth of field effect. Learn manual mode.
Core Web Vitals Simulator - Online Learn How to Improve LCP/INP/CLS
Adjust page characteristics (image size, server delay, layout shift) and see the simulated Core Web Vitals scores. Understand what impacts performance.
Enhanced Color Blindness Simulator - Image & UI Combined
Upload an image and also see a UI mockup under different deficiencies side‑by‑side. Powerful for inclusive design.
SQL Injection Simulator - Online Educational Sandbox
Test SQL injection inputs on a mock database and see the resulting query. Learn how to prevent SQLi. No real data.
Projectile Motion Simulator - Online Angle & Speed
Set launch angle, initial speed, and height. See the trajectory, max height, and range plotted on a canvas. Learn kinematics.
Telescope Field of View Simulator – Online Eyepiece & Object
Input telescope and eyepiece parameters to see a simulated view of the Moon or Andromeda. Plan observations.
Magic 8-Ball Simulator - Online Ask and Shake
Ask a yes/no question and click to reveal a classic Magic 8-Ball response. Animated shake effect. Nostalgic fun, pure local randomness.
Brute Force Time Estimator - Online Password Cracking Simulation
Enter a password and see the estimated time it would take to crack using brute force at different speeds. Educational.
Tennis Scoring Simulator - Online Point Tracker
Keep track of a tennis match: points, games, sets, and deuce. Supports tiebreak. Great for friendly matches. Local.
Barcode Scanner Simulator – Online Enter Number & Visualize
Type a UPC or EAN number and see how a laser scanner would identify it, plus check digit validation.
Steroids IR Spectrum Simulator - Online Simple Chemistry Tool
Select functional groups to see an approximate IR absorption spectrum. Learn spectroscopy visually. All local.
Depth of Field Simulator - Online Blur Preview
Visualize how aperture, focal length, and subject distance affect background blur. Interactive DOF calculator.
Cron Job Simulator - Online Visual Schedule Tester
Set a cron expression and see a calendar of the next 1,000 execution times. Never miss a schedule again.
WebSocket Load Tester - Online Simulate Many Clients
Open many parallel WebSocket connections and send messages. Test your server's concurrency. All from your browser.
Dice Roll Simulator & Stats - Online Massive Roll Trials
Roll any number of dice thousands of times and see a live bar chart of the sum distribution. Great for game designers.
Hover State Simulator - Online Test :hover :active :focus
Type any CSS selector with :hover/:active/:focus and see the styles applied live. Perfect for debugging interaction states.
Random User Activity Simulator - Online Test Idle Logic
Simulate random mouse moves, clicks, or keystrokes to test idle‑timeout logic. Stops when you move the mouse. Dev test.
Page Replacement Simulator - Online FIFO, LRU, Optimal
Simulate memory page reference strings with FIFO, LRU, and Optimal algorithms. See page fault count. OS concept demo.
Solar System Simulator 2D - Online Top‑Down Orrery
Watch the planets orbit the Sun in a top‑down 2D view. Adjust speed and zoom. Distances not realistic; beautiful model.
Camera Exposure Simulator - Online Learn ISO, Aperture, Shutter
Adjust ISO, aperture, and shutter speed sliders and see how it affects the exposure of a sample scene. Learn photography basics.
Paper Fold Simulator - Online Virtual Origami Practice
Fold a virtual square paper step by step with crease lines and visual previews. Practice origami basics without wasting real paper. All canvas‑based.
Color Blindness Simulator - Online Vision Deficiency Preview
Simulate how images and UI elements appear to users with various types of color blindness. Upload or paste image URL. Promote inclusive design.
Solar Eclipse Simulator - Online Visualize Totality
Drag to see how a solar eclipse occurs. Visualize the moon's shadow. Educational and interactive.
Lunar Lander Simulator - Online Retro Thrust Game
Control a lunar module and try to land softly on the moon. Manage fuel and thrust. Classic arcade physics. Canvas.
Page Speed Simulator - Online Estimate Load Metrics
Enter a URL and get a rough client-side performance simulation: request count, DOM size, and potential speed tips. No real Lighthouse.
Image Color Blindness Simulator - Upload & See
Upload any image and view it as a person with deuteranopia, protanopia, or tritanopia would. Promote inclusive design.
Coin Flipper - Online Heads or Tails Simulator
Flip a virtual coin to make a decision or settle a dispute. Realistic animation and fair random outcome. Simple, fast, and always available.
Online Dice Roller - Virtual Dice Simulator
Simulate rolling dice for board games, RPGs, and decision making. Choose number of dice and faces. Fun, lightweight, and no download required.
Telescope FOV Simulator - Online Eyepiece & View Preview
Select telescope and eyepiece parameters to see the field of view circle on a simulated night sky image.