UD5 Toolkit
Battery Life Calculator - Online Device Runtime Estimator
Estimate how long a battery will last given capacity (mAh/Wh) and load current. Also computes backup time for power banks. Quick and local.
Bluetooth Battery Monitor - Online Read Device Levels
Bluetooth Battery Monitor
Check battery levels of your Bluetooth devices instantly – no app, no setup. Works directly in your browser using Web Bluetooth.
No devices connected
Click "Scan for Devices" to find nearby Bluetooth accessories with battery service.
Scanning...
Looking for Bluetooth devices...
Frequently Asked Questions
This tool uses the Web Bluetooth API to detect nearby Bluetooth Low Energy devices that advertise the standard Battery Service (UUID 0x180F). Once connected, it reads the Battery Level characteristic (0x2A19) and displays the percentage. It can also listen for battery changes in real time. Everything runs locally in your browser – no server, no tracking.
Any Bluetooth device that follows the standard Battery Service specification. This includes many wireless headphones (Sony, Bose, JBL), fitness bands, smartwatches, mice, keyboards, game controllers, and even some smart home sensors. Note: the device must be BLE‑enabled and currently advertising the service.
Make sure Bluetooth is turned on (computer and device), put the device in pairing/discoverable mode, then click "Scan for Devices". A browser pop‑up will list available devices. Choose your device and accept the connection request. The battery level appears instantly.
Yes, on Android devices using Chrome or other Chromium‑based browsers. Web Bluetooth is not yet supported in Safari on iOS, but you can use the Bluefy or WebBLE apps to enable it. Desktop Chrome, Edge, Opera, and Samsung Internet all work.
Absolutely. The connection is established entirely inside your browser. No battery data or device identifiers are ever sent to our servers. The tool does not use cookies, analytics, or any form of tracking. You stay in full control.
First, ensure Bluetooth is enabled and the device is awake and in range. Some devices need to be unpaired from the system before they appear in the browser chooser. If the device does not implement Battery Service (0x180F), it won't be listed. Try refreshing the page and scanning again.
Yes! After connecting one device, click "Scan for Devices" again to add another. Each device has its own card with a live battery gauge and a disconnect button. Practical limits depend on your Bluetooth adapter and browser.
Defined by the Bluetooth SIG, the Battery Service (0x180F) exposes the Battery Level characteristic (0x2A19) that reports charge as a percentage (0–100). Some manufacturers also include a Battery Power State, but this tool focuses on the simple level readout that almost all BLE devices support.
Launch Handler API Demo - Online Control App Launch Behavior
Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.
Compression Streams API Demo - Online Gzip/Deflate Raw
Compress and decompress text using the browser's native Compression Streams API. See the binary output size.
Permissions Query API Demo - Online Check All APIs
Query the permission state of camera, microphone, geolocation, and more. See the response and learn the API.
Gamepad Tester - Online Button & Axis Visualizer
Connect a game controller and see every button press, axis movement, and vibration test. Uses the Gamepad API.
Pointer Events Playground - Online Mouse, Touch & Pen
Unified input demo: see pressure, tilt, and type from any pointer. Compare pointerType values. Essential for drawing apps.
Web Animations API Sandbox - Online JS Animation Editor
Write JavaScript using element.animate() and see the result in a live preview. Compare with CSS keyframes. Debugger included.
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.
Built-in Translation API Demo - Online On‑Device Translate
Test the experimental Translation API to translate text between languages directly in the browser, without cloud calls. Check support and copy the JavaScript starter.
ImageDecoder API Demo - Online Progressive Decode
Decode an image progressively using the ImageDecoder API. See partial results and metadata. Modern alternative to <img>.
WebCodecs Video Frame Reader - Online Decode & Display
Decode individual video frames from a local file using the VideoDecoder API. Step through frames. Cutting‑edge browser feature.
FedCM Demo - Online Federated Credential Management
Experiment with the Federated Credential Management API. Simulate a sign‑in flow without third‑party cookies. Privacy‑first.
Web HID Explorer - Online List & Read HID Devices
Request HID devices and list them. Read input reports and send output. For custom hardware and controllers.
Idle Detection API Demo - Online User Activity Monitor
Request permission and detect when the user is idle (away from keyboard). See screen lock state. For native‑like apps.
Web OTP API Demo - Online Auto‑Read SMS Codes
Demonstrate how the Web OTP API automatically reads one‑time codes from SMS (mobile). Simulation with a fake SMS input.
Web Locks API Demo - Online Resource Coordination
Acquire and release locks across tabs. Prevent race conditions in IndexedDB or localStorage. Visual queue and lock state.
Gamepad API Tester - Online Visual Controller Check
Connect a gamepad and see all button presses and axis movements visually. Check that every input is detected correctly.
Vibration API Demo - Online Test Haptic Feedback
Trigger different vibration patterns on mobile devices. Test if your phone supports haptic feedback. Simple demo.
Network Information API Checker - Online Downlink Speed
Display your effective connection type (4g, 3g, etc.) and downlink speed using the Navigator API. Adapt your app accordingly.
Battery Status API Viewer - Online Check Level
See your device's battery level, charging status, and discharge time using the Battery Status API. Fun utility.
Screen Orientation API Tester - Online Lock & Check
Check current screen orientation and test the lock API. Useful for mobile web apps. Demo with code.
Popover API Demo - Online No‑JS Tooltips & Menus
Test the new HTML popover attribute for creating accessible tooltips, menus, and dialogs without JavaScript. Copy code snippets.
View Transitions API Demo - Online Smooth Page Switch
See the View Transitions API in action. Cross‑fade and morph between two states. Copy the JavaScript starter code.
Clipboard API Tester - Online Read & Write Sandbox
Experiment with the Async Clipboard API: read/write text and images from the clipboard. Verify permissions and see demo code.
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.
API Status Checker - Online Test Endpoint & Response
Enter an API URL and quickly check its HTTP status code and response time. See response headers and body. Browser fetch.
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.
Battery Saver Dark Screen - Online Minimal Power Page
A completely black page to save battery on OLED devices. Click to go fullscreen. Simple utility.
Battery Series/Parallel Calculator - Online Voltage & Capacity
Combine multiple identical batteries in series and parallel and see the resulting voltage and total capacity. Electronics helper.
Random JSON Generator - Online Create Sample API Responses
Generate random JSON data with customizable fields (users, products, orders). Useful for frontend mocking. All local.