Month: October 2020

The Web Bluetooth API lets websites discover and communicate with devices over the Bluetooth 4 wireless standard using the Generic Attribute Profile (GATT). It is currently partially implemented in Android M, Chrome OS, Mac, and Windows 10. This sample illustrates the use of the Web Bluetooth API to start and stop characteristic notifications from a nearby Bluetooth Low Energy Device. You may want to try this demo with the BLE Peripheral Simulator App from the Google Play Store and check out the Notifications (Async Await) sample. var myCharacteristic; function onStartButtonClick() { let serviceUuid = document.querySelector(‘#service’).value; if (serviceUuid.startsWith(‘0x’)) { serviceUuid = parseInt(serviceUuid); } let characteristicUuid = document.querySelector(‘#characteristic’).value; if (characteristicUuid.startsWith(‘0x’)) { characteristicUuid = parseInt(characteristicUuid); } log(‘Requesting Bluetooth Device…’); navigator.bluetooth.requestDevice({filters: [{services: [serviceUuid]}]}) .then(device => { log(‘Connecting to GATT Server…’); return device.gatt.connect(); }) .then(server => { log(‘Getting Service…’); return server.getPrimaryService(serviceUuid); }) .then(service => { log(‘Getting Characteristic…’); return service.getCharacteristic(characteristicUuid); }) .then(characteristic => { myCharacteristic = characteristic; return myCharacteristic.startNotifications().then(_ => { log(‘> Notifications started’); myCharacteristic.addEventListener(‘characteristicvaluechanged’, handleNotifications); }); }) .catch(error => { log(‘Argh! ‘ + error); }); } function onStopButtonClick() { if (myCharacteristic) { myCharacteristic.stopNotifications() .then(_ => { log(‘> Notifications stopped’); myCharacteristic.removeEventListener(‘characteristicvaluechanged’, handleNotifications); }) .catch(error => { log(‘Argh! ‘ + error); }); } } function handleNotifications(event) { let value = event.target.value; let a = []; // Convert raw data bytes to hex values just for the sake of showing something. // In the “real” world, you’d use data.getUint8, data.getUint16 or even // TextDecoder to process raw data bytes. for (let i = 0; i < value.byteLength; i++)… Read more

Bluetooth Smart is an emerging short range wireless technology aimed for low power devices. Bluetooth 4.2 core specification provides various methods to secure the communication between devices and establish trusted connections. This paper describes the design considerations to secure the Bluetooth smart devices. 1. Introduction Bluetooth smart (also known as Bluetooth low energy or BLE) is introduced in the legacy Bluetooth 4.0 specification by Bluetooth special interest group. Bluetooth smart is primarily designed for low power embedded devices with limited computation capabilities. With expeditious growth in the IoT technology, Bluetooth Low Energy Module has become substantiate criterion for the smart devices. Bluetooth specification supports the asymmetrical architecture of the LE devices. Memory and processing power requirements of peripheral devices are much lower than the central. This will be a great advantage in case of single mode – peripheral only devices. Device that acts always as peripheral can be designed with low memory, longer battery life and low power consumption. Low power smart wearable devices available in market such as Bluetooth heart rate monitors, blood pressure monitors, fitness kit, smart watches etc. run on a small coin cell battery for years. 2. Low energy, Low security Like any other wireless technology, BLE is no exception from security threats. While Bluetooth LE beacons bring lots of potential in the IOT design, security threats such as device tracking, eaves dropping, and man in the middle attack are increasing significantly. BLE devices are designed to broadcast MAC, UUID and service information’s at a predefined… Read more