Every question the Connected Devices pages answer
The 12 connected devices pages answer 36 named questions between them. Every one is listed below, and every link lands on the paragraph that answers it rather than the top of the page.
Connect a Bluetooth Heart Rate Monitor to Your App (2026)
- Which Bluetooth UUIDs does a heart rate strap use, and do I need one integration per brand?One integration covers conforming monitors. The Bluetooth SIG's assigned-numbers registry lists the Heart Rate service as 0x180D, the Heart…
- What does the Body Sensor Location characteristic (0x2A38) actually tell my app?It reports where the monitor says it sits on the body. Treat it as provenance and as a UI label, not as anything you compute with. Read it…
- Why do a chest strap and a wrist watch report different heart rate for the same workout?Because they are different measurements, not the same measurement done well and badly. Wrist optical sensors and chest straps differ in…
Reading Cycling Power, Cadence, and Speed Sensors in an App
- What are the BLE UUIDs for cycling power, cycling speed and cadence, and running speed and cadence?Per the Bluetooth SIG's assigned-numbers registry, Cycling Power is service 0x1818 with Cycling Power Measurement 0x2A63, Cycling Speed and…
- My trainer reports power over both FTMS and the Cycling Power service — which one should I record?Pick one and record which one you picked. A smart trainer can expose the standalone Cycling Power service 0x1818 and Indoor Bike Data…
- How should a cycling app remember multiple BLE sensors between rides?Store the pairing by role rather than as a flat device list. Riders think in terms of a power source, a cadence source and a heart rate…
What Is FTMS? The Bluetooth Fitness Machine Service (2026)
- Which Bluetooth service UUID is FTMS, and which characteristic carries each machine type's data?The Bluetooth SIG's assigned-numbers registry lists the Fitness Machine Service as 0x1826. It defines a distinct data characteristic per…
- Can my app actually control speed or resistance through the FTMS Control Point (0x2AD9)?The characteristic exists in the service, and Fitness Machine Status 0x2ADA is there for the machine to report state changes back. Whether…
- How do I discover what an FTMS machine supports before rendering controls for it?Use the discovery characteristics the service provides. Fitness Machine Feature 0x2ACC declares the machine's features, and the Supported…
Treadmill App Integration: Reading FTMS Treadmill Data
- Which BLE characteristic carries treadmill speed and incline data?Treadmill Data, characteristic 0x2ACD, under the Fitness Machine Service 0x1826, per the Bluetooth SIG's assigned-numbers registry. A…
- Can a third-party app change treadmill speed or incline over Bluetooth FTMS?Sometimes, and you have to test per model. The Fitness Machine Control Point 0x2AD9 is the characteristic for writing commands, with…
- How should a treadmill app use the Supported Inclination Range characteristic (0x2AD5)?Read it once at connection time, cache it per device, and let it drive the interface. Two things follow. First, presentation: do not render…
Smart Bike Trainer Integration: FTMS and Cycling Power
- Should a smart trainer app read Indoor Bike Data (0x2AD2) or the Cycling Power service (0x1818)?Many trainers expose both, so the answer is to choose deliberately rather than subscribe to everything. Indoor Bike Data 0x2AD2 sits under…
- Does every FTMS smart trainer accept resistance or target power commands from a third-party app?No, and you should assume nothing from the characteristic list. The Fitness Machine Control Point 0x2AD9 exists in the service, with…
- Which characteristics tell me a smart trainer's resistance and power limits?Supported Resistance Level Range 0x2AD6 and Supported Power Range 0x2AD8, both under the Fitness Machine Service 0x1826, alongside Fitness…
Getting Rowing Machine Data Into an App (2026)
- Which Bluetooth characteristic carries rowing machine data under FTMS?Rower Data, characteristic 0x2AD1, under the Fitness Machine Service 0x1826, per the Bluetooth SIG's assigned-numbers registry. A…
- Why does my rowing machine expose a proprietary interface instead of FTMS Rower Data?Some manufacturers document their own interfaces alongside or instead of the standard service, and we make no claims about which ones,…
- How should a rowing app record a session when the ergometer only streams live data?Build the session record yourself, because FTMS streams live and hands you no history. That means you own the timestamping, the pause…
Live Heart Rate From Apple Watch in Your App (2026)
- Does an HKWorkoutSession give higher-frequency heart rate than reading HealthKit samples on Apple Watch?Yes, and Apple states it directly: all workout sessions generate high-frequency heart rate samples. Apple also documents that the session…
- What happens to my watchOS workout session if the user starts a workout in Apple's Workout app?Yours ends. Apple documents that Apple Watch runs one workout session at a time, and that if a second workout starts while your workout is…
- Can an Apple Watch workout session keep running while the watch is locked and show data on iPhone?Both are documented capabilities of workout sessions. Apple lists background execution while the watch is locked, mirroring the workout to…
Wear OS Health Services for Live Workout Data (2026)
- Should a Wear OS app use ExerciseClient or PassiveMonitoringClient for heart rate?It depends on whether a workout is in progress. Google describes ExerciseClient as the API for managing workouts, setting exercise goals,…
- What does Health Services on Wear OS do about battery and cross-app consistency?Google makes two specific claims. On power, Health Services conserves battery by using sensor configurations that are optimized for power…
- Does Wear OS Health Services replace pairing a Bluetooth sensor to the watch?For anything the watch itself senses, it generally should be your default. It does not help for signals that come from hardware the watch…
ANT+ vs Bluetooth for Fitness Sensors (2026)
- Is the ANT+ certification program really discontinued, and do existing ANT+ sensors stop working?Reported, not verified by us. Multiple consistent notices published in January 2025, including DC Rainmaker and the5krunner and community…
- Can an iPhone or Android phone receive ANT+ sensor data without extra hardware?Historically this has needed more than the phone itself: additional hardware, platform-specific plugin software, or a handset whose…
- Should a new fitness app in 2026 implement ANT+ support alongside Bluetooth Low Energy?Our judgement is no, not as a second radio integration. Build on Bluetooth Low Energy and the SIG-standard profiles, which are documented,…
Web Bluetooth for Fitness Apps in the Browser (2026)
- Can a web page use Web Bluetooth to connect a heart rate strap in Safari on iPhone?No. Per the caniuse dataset, Safari does not support Web Bluetooth on desktop or on iOS. A third-party iOS app exists that polyfills the…
- Which browsers support Web Bluetooth for talking to fitness sensors and machines?Per the caniuse dataset, the supporting browsers are Chrome from version 56, Edge from 79, Opera from 43, and Samsung Internet from 6.2.…
- Does a Web Bluetooth fitness page read the same GATT services as a native app?Yes, and that is the main reason to consider it. A browser page connects to the same SIG-standard services a native application would:…
Core Bluetooth for Fitness Devices on iOS (2026)
- Which Info.plist key does Core Bluetooth require on iOS 13 and later?NSBluetoothAlwaysUsageDescription. It is required to access Core Bluetooth APIs from iOS 13 onward; iOS 12 and earlier used…
- Should an iOS fitness app use CBCentralManager or CBPeripheralManager for a heart rate strap?CBCentralManager. Apple describes the central role as scanning for, connecting to, and managing peripherals, which is exactly what an app…
- Can I subclass CBCentralManager or CBPeripheral to make my BLE fitness layer testable?No, and Apple says so directly: don't subclass any of the classes of the Core Bluetooth framework, because overriding these classes isn't…
Testing Bluetooth Fitness Device Integrations (2026)
- Can I test a Bluetooth heart rate strap integration without physical hardware?Not the live radio behavior. A physical device is the only reliable test target for live BLE behavior, so the productive move is designing…
- What should I record from a BLE fitness sensor or machine to replay as a test fixture?Two things are enough for deterministic replay: the device's advertised services and characteristics at connect time, and the stream of…
- Which Bluetooth fitness device failures only show up with real hardware in the room?In our judgement, four categories. First-time pairing, where permission prompts, bonding and manufacturer quirks all arrive at once for a…
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