UD5 Toolkit
Speaker Polarity Test – Online Click & Listen
Generate a pop signal to determine if speakers are wired in phase. Quick stereo test.
Reaction Time Test
Online click & sound reflex measurement – accurate and instant
Click or tap to start
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Frequently Asked Questions
A reaction time test measures how quickly you respond to a stimulus. In our tool, you can test visual reaction (screen color change) or auditory reaction (sound beep). It's used in sports, gaming, and cognitive research.
Average visual reaction time is around 200–250 milliseconds. Auditory reactions are typically faster, around 150–200 ms. Factors like age, fatigue, and practice can influence your score.
Regular practice, staying hydrated, getting enough sleep, and reducing distractions can improve reaction speed. Physical exercise and cognitive training games also help.
The test uses high‑resolution timestamps and Web Audio API for precise beep timing. However, device latency (screen, Bluetooth headphones) can add a few milliseconds. For best results, use wired accessories and a fast device.
Sublimation Press Time Calculator – Online Mug/T‑Shirt
Look up recommended time and temperature for various sublimation blanks. Quick reference.
Astigmatism Self‑Check Chart – Online Dial & Lines
Display an astigmatism dial and instructions for self-assessment. Educational, not a medical diagnosis.
Spelling Test Practice - Online Audio Dictation & Typing
Hear a word spoken by browser TTS and type the spelling. Choose difficulty or paste your own list. Great for kids. Local only.
Geolocation Override Tester - Online Simulate Any Location
Override your browser's geolocation to any coordinates and test how your app responds. For development and privacy testing.
Audio/Video Sync Tester - Online Lip Sync Check
Load a video and visually check if audio aligns with lips. Use frame‑by‑frame stepping. Debug playback issues.
Screen Wake Lock Tester - Online Keep Screen On
Toggle a screen wake lock to prevent the device from dimming or sleeping. See the lock state and learn the API.
Accept‑Language Header Visualizer - Online Locale Match
Paste your Accept‑Language header and see which languages your site should serve based on quality values. Internationalization helper.
Network Throttle Simulator - Online Slow 3G & Offline Test
Test how your page loads under slow, 3G, or offline conditions by intercepting fetch and applying delays. No DevTools needed.
Geolocation API Simulator - Online Test Coordinates
Override your browser's geolocation to any coordinates and test how your app responds. For development and privacy testing.
Screen Orientation API Tester - Online Lock & Check
Check current screen orientation and test the lock API. Useful for mobile web apps. Demo with code.
Fullscreen API Tester - Online Request & Exit Demo
Test the Fullscreen API: request fullscreen on a colored div, detect changes, and copy the JavaScript boilerplate.
Web Share API Tester - Online Demo & Code
Test the Web Share API by sharing text, links, and files directly from the browser. Check compatibility and see example code.
Browser Color Gamut Test - Online P3 or sRGB?
Check if your browser and display support the wider DCI‑P3 color space. See the difference with a simple test pattern.
Palindrome Tester - Online Phrase Checker
Enter any phrase and instantly see if it's a palindrome, ignoring spaces and punctuation. Fun for word nerds.
Fake ID Number Generator - Online Test SSN/SIN Lookalike
Generate random, formatted ID numbers that match pattern rules for various countries. For testing input validation. No real data.
HTTP Request Composer - Online Build & Send Requests
Pick a method, URL, headers, and body, then send an HTTP request directly from your browser. Debug APIs easily.
Media Device Tester - Online Check Camera, Mic & Speaker
Quickly test if your webcam, microphone, and speakers work correctly. See live video and audio meter. No data sent.
Fuzzy Data Generator - Online Create Random Records
Generate random but realistic‑looking data arrays (users, products, orders) with typos and missing fields. For test robustness.
Emoji Reaction Overlay Generator - Online Video Comment Style
Add floating emoji reactions (like live streams) to any screenshot or photo. Export as still image. Fun social media tool.
Eye Dominance Test - Online Find Your Dominant Eye
Simple interactive eye dominance test: hold up a virtual dot and see which eye stays aligned. Educational.
Iframe Sandbox Configurator - Online Test Permissions
Build an iframe with different sandbox flags and see live which features are blocked. For secure embedding.
Elapsed Time Calculator - Online Duration Between Dates/Times
Enter two date‑time values and get the exact years, months, days, hours, minutes difference. Word output also.
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.
Digital Binary Clock - Online Time in Bits Fullscreen
A beautiful full‑screen binary clock showing hours, minutes, seconds in glowing bits. Dark mode perfect for desks.
Test Credit Card Validator - Online Luhn Check & Issuer
Paste a test card number to verify Luhn algorithm, identify issuer (Visa, MC), and check length. No real data.
Speaker Test Tones - Online Left/Right Channel & Sweep
Play left‑only, right‑only, and frequency sweeps to test your speakers or headphones. Quick audio check.
Microphone Sensitivity Tester - Online Input Level Meter
See a live VU meter of your microphone's input level. Test if your mic is working and adjust gain. Privacy‑friendly.
Minutes to Decimal Hours - Online Time Conversion Tool
Convert minutes to decimal hours and vice versa. Essential for billing and payroll. Instant conversion with a handy chart.
Click Counter - Online Tally & Increment Tool
A large, simple button to count anything. Plus / minus, reset, and save count to localStorage. Works offline.