Looking to go deeper into IoT? Check out my video on connecting an Arduino Uno r4 to a web server Connecting Arduino to the Internet - Fullstack Internet of Things ( IoT ) with Expo ukposts.info/have/v-deo/hHWWfpB6hollmH0.html

thanks you so much. I has found this cource for bluetooth low energy for a long time. It realy useful for me!

I watched your previous video, then I discover expo, I thought okay, maybe it's not supported, and now i find you again with a great video. Thank you very much! It helped me a lot with my final project at University

This was a life saver! Thank you.

Perfect! Thanks for this video, this is exactly the use case I'd be interested in.

Wonderful video. Ive been waiting for bluetooth with expo for some years now.

In the requestPermissions method you return true in the else clause. Will it not be impossible to tell if an ios device has BLE permissions enabled or not then? I have used the onStateChange method from ble-plx library to check this but is there any better way?

H, Dan I tired to connect and stream data from "O2Ring " which monitor heartrate,spo2,rtwave and pulse. but i am not able to get data. can you please help me out

You are insane! Thank you very much.

hi I have a question for you. When we close the app do we need to un-monitor the characteristic as well? if not, what will happen from hardware side. Will it keep sending the values on notification channel even the app is off?

Hey Dan thanks for this brotha. Just subscribed. If I am using an eeg headset how would I go about creating 5 different wave type values? I have done this in MAX and am trying to transfer it to this and make it an app. I really need some help at this point. ~ dnt

I am facing with a problem but idk how to resolve It. I have a service callback in my esp32 onConnect and onDisconnect and It works when I connect it and if I disconnect the Bluetooth from my phone but if I send the order from the library react-native-ble-plx It disconnects from the phone but onDisconnect from my esp32 does not trigger to advertice so if I Bluetooth scan again my esp32 does not show until I reboot. Great video.

i'm a beginner to react and app dev but got a project to create a simple controller app to connect to raspberry pi through ssh, do you have a video or recommendation on how i can do it?

I keep getting build errors when running command "npx expo run:android". "BUG! exception in phase 'semantic analysis' in source unit '_BuildScript_' Unsupported class file major version 64". I have double and triple checked that everything is installed and all the environment variables are set properly. Does anyone have any ideas or have seen this? Any help would be greatly appreciated.

Hi Dan, Thank you for the amazing tutorial. It is truly nice to have someone finally walk through how to make this work without ejecting from expo. I noticed there is no license specified in your Github project repository. Given that this is a tutorial, do we have permission to use your code as a foundation for our own projects?

awesome

Hey Dan great video btw but I wanted to know that in order to build do we need Android studio like for sdk stuff configured on our system or just it expo will build it online?

Hi Dan, thanks for the tutorial first of all! I found it only yesterday and it's already helped a lot, but I've been stuck just trying to build the application which seems impossible to me. Did you use an Android Studio emulator for this? I have been unable to get my emulator to work.

Hi Dan, thanks for these videos, you help a lot! I need to use this in a project but I need to communicate with the device (asking things - using write()). In your case, for example, it would ask you what battery level your Heart Rate Device has, or make it beep to find the device. I have looked at the documentation a bit but BLE is something very new for me, if you could confirm that it really is possible, you would help me a lot! Or even if you could make a quick video on how to do this. Greetings, I appreciate you man!

Hi again! I hope you're well. I've been working a few weeks with the managed BLE + Expo project and need to automatically connect to the device when I open the app again, or even keep BLE connected and paired with the device. Do you have any idea how this could be possible with this tech stack that you use in the video? I really appreciate your help, greetings!

Hello, thanks for this video ! I have a question, when i run the command npx expo run:android, i get this error: Task :react-native-ble-plx:compileDebugJavaWithJavac FAILED What went wrong: Execution failed for task ':react-native-ble-plx:compileDebugJavaWithJavac'. > Could not resolve all files for configuration ':react-native-ble-plx:androidJdkImage'. > Failed to transform core-for-system-modules.jar to match attributes {artifactType=_internal_android_jdk_image, org.gradle.libraryelements=jar, org.gradle.usage=java-runtime}. > Execution failed for JdkImageTransform: C:\Users\K\AppData\Local\Android\Sdk\platforms\android-34\core-for-system-modules.jar. > Error while executing process C:\Program Files\Java\jdk-21\bin\jlink.exe with arguments {--module-path C:\Users\K\.gradle\caches\transforms-3\6683fa48bcb440c054791c94c0688110\transformed\output\temp\jmod --add-modules java.base --output C:\Users\K\.gradle\caches\transforms-3\6683fa48bcb440c054791c94c0688110\transformed\output\jdkImage --disable-plugin system-modules} Can you help me

Hi Dan, I have a question. Why you pass allDevices and connectToPeripheral function from useBLE() custom hook throught function components parameters (DeviceConnectionModal) instead of calling useBLE() in this function component? Can I call this custom hook anywhere? I have this dubt because I have this use case and I want to use useBLE() in another function component and I'm getting null or undefined in everything data and functions. Thanks in advance!

Hey, Thanks for sharing. I have a question. Once a device is subscribed with a service characteristics then after some time it is getting auto disconnect. Any clue why this is happening? The error object is { "errorCode": 201, "attErrorCode": null, "iosErrorCode": 6, "androidErrorCode": null, "reason": "The connection has timed out unexpectedly.", "deviceID": "6C2E6353-13CC-BD15-A46C-471BAA05F2DA", "serviceUUID": null, "characteristicUUID": null, "descriptorUUID": null, "internalMessage": null }

Hi Dan, thank you for the video. I have some issues when I follow your old video. I use getServicesAndCharacteristics and monitorCharacteristicForService function and I use isDeviceConnected Function to make sure the Indicator device is connected. I want to get the weight value from the indicator device but the value return null. How can I do in this case? Thanks !!

Hello Dan, I propose that you make an update by adding a local push notification when the hert rate rise above a certain value, for example 120bpm. The cool thing is that it could be done while the app is in the background, you could teach a lot about this topic that there is much more ignorance on the part of the community, at least I speak for myself. I wait your answer!

Hi Dan. I love your videos! Please keep'em rolling. Everyone asked you for a demonstration in Expo, and so you did. You previously used react-native vanilla in some of your videos. Which would you recommend using? Are there exceptions like for freelance one is better than the other, but then if used professionally the other is recommended, and for hobbyists, etc...?

Hey Dan, Great Job!!! I've extended my app to use your custom useBle hook across multiple components on multiple screens, and I have maybe a tricky question for you (or maybe it's more fundamental React): I was building my first app with ble pxe library when I saw your useMemo approach (I was stuck on maintaining one instance of bleManager - THANK YOU), and it worked... until I added multiple components (particularly on different screens) calling APIs from the custom useBle hook... what seems to be happening is that each component (on its initial render) calls one of the APIs from the useBle custom hook, which seems to refresh/rerun/reinitialize the useBle custom hook (at least the initial time for each screen), which seems to (a) clear or (b) create an additional instance of bleManager (I"m not sure which one, but I'm thinking it reruns your useMemo, hence dropping the initial bleManager and replacing it with a new bleManger, possibly without properly closing the initial one, and losing the connection). As a specific example: I scan and auto-connect fine on the first screen (just like you did; everything including measurements work)... but I have a second screen (with a different component) that let's the user disconnect from that initially connected device, rescan and connect to another device manually... when I move to that second screen (note I'm already connected to a device), the app seems to recreate bleManager (or possibly create a second one; again, I'm not positive here), which causes the app to lose the connection to the device I was connected to (I have confirmed it loses connection as any action before I open the second screen works fine, and any action after I open the second screen gives me the error that the device is not connected). I wrote a workaround (basically uses isDeviceConnected to see if the device that my RTK state says is connected is in fact connected, and if not, it reconnects with connectToDevice), but that seems clunky and I'm guessing you might have a better way? Note that I tried putting bleManager in my RTK state, which actually seems to work, but that too doesn't feel right (and I get nonSerializable errors from RTK, which I can suppress, but that doesn't seem right... I also tried serializing bleManager before putting it into my state to avoid the nonSerializable errors with JSON.stringify, then using JSON.parse to pull it back out, but I confirmed the result is not the same - maybe that's obvious, but it wasn't to me so I gave it a shot and wanted to let you know). So, all that to ask as I'm sure others will run into this as well: any advice for creating a single, persistent bleManager that survives react native re-renders, multiple components calling useBle on multiple screens?

Great video! 2 Questions 1. Was prebuild necessary since I assume npx expo run:android would run prebuild regardless 2. You can still build iOS Locally right? Thre should be no reason to use EAS Build if you have xcode setup

Hi so I have a random question that kinda pertains to the video, So im looking to connect a bluetooth clicker to an app like you hit a button ( only one button) and it does something in the app. Is it the same process as the other videos you've done? Im new to react native and trying to figure this all out.

Hi Dan, I know I've asked you a lot of questions, but I have one last question left. I want to get the application I made as apk, but the apk I got from the "eas" page comes with an expo interface and works by communicating with a local server, that is, our terminal, but I want a pure apk directly.

Great video! grats! i am having some issues when i am trying to deploy it, can u please tell me wich version of SDK and java are u using? It is necessary install gradle? thanks!

Hey Dan! Thanks for the tutorial! How exactly did you get your project running on your real Android device? I am trying to do this so I can test the Bluetooth functionality. It seems that Android Studio does not support Bluetooth.

nice

Hi Dan, thank you and congratulations on your videos, I found them a few weeks ago. I started a personal project and bought some Beacon Proximity devices (Estimote). I'm stuck at the beginning because they don't provide a React Native library, so I'm trying to create a bridge between the native SDKs (Android and iOS) and Expo or React Native. It's proving to be very difficult because I can't find a clear guide that explains how to do it, and my knowledge of Java/Kotlin and Swift is almost non-existent. I have a question for you, does the library you mention in the project work for proximity devices with BLE technology? I found this more up-to-date library, react-native-ble-manager, do you think it's better? Thanks!!!

nice video....do i have to do the eas-build setup if clone and run the project?

Hey Dan, thank you so much for this video! I found it extremely useful and easy to follow. I have been looking for this sort of breakdown of implementing BLE in react native for a while. While following the tutorial I did come across an error I wanted to ask you about. I am receiving a render error with the message " Cannot read property 'createClient' of null". Is this something you have come across before or do you have any tips on where I may look to fix this error? Thanks again for you help and for the great tutorial!

Hi, i'm use "eas build --profile development --platform android" to prove it on my smartphone instead expo prebuild, that i understand serves the same purpose, but i have the exception of "Cannot read property 'createClient' of null" when BleManager() constructor is called, this could be due to use another method to build the app?

Hello Dan, thank you for the great video. I have a question for you. How can we run this project on our own physical device? Normally, I can run my expo projects on my own phone, but it didn't work for this project. However, it works on a virtual device.

do we need to pay apple developer program ( 99$ ) to use ble on iphone? thanks you for answers all.

Hello, Dan! This video was AMAZING!! Love it very much:) But can you make an app that connects to bluetooth headphones and disconects when you click?

Hi dan can you mention the java sdk version, Gradle version, that ble supports that would be a grate help.

I'm having difficulty running unit tests with React Native BLE Manager. Every time I try to execute the command 'yarn test,' it fails, and I can't find any relevant content on it either. Do you know how to do it?

Hello, i have a problem after "npx expo prebuild" i dont see any phone on my screen and after "npx expo run:android" i get error "CommandError: No Android connected device found, and no emulators could be started automatically." Did i misss something or it was explained in your other video?

Hi Dan and thanks for the helpful videos! Could you show how to scan for BLEs when the app is off and the screen is off. As I undestood after android 11 this task is quite challanging and there is almost no info that I can find on that topic.... thanks in advance

Hi Dan, first of all, excellent video, it is very helpful, the second thing is that I'm trying to create something similar to what you show here, but the BPM data read them with the app so this is closed and then send this data to a backend and then treat them for features such as sms or emergency calls according to the data, do you see it viable? do you know how I could guide me? I would appreciate any help. its for my thesis:D

Hi Dan, thank you for this great tutorial. i get error cannot read property 'useMemo' of null, any idea to fix it?

Hello, How can i do if i want to build and app that read a serial data from a sensor, it is a microcontroller build it by me, thanks for the info.

Hey dan, amazing video first of all! Second, i have a question in regards to this…will this still work if i change from a managed workflow to a bare using npx expo pre build? Im also using Expo Go at the moment

Hey , Dan i am using and esp32 module to connect it with mmy react native app to deliver heart rate with a heartrate sensor will this code work for it??

hey, thanks for the video, will help me a lot. I am stuck with this error: TypeError: null is not an object (evaluating '_BleModule'), double checked permissions, followed exactly what you did, no success...

Can we publish or run a production version of such an app, since it cannot be ran on Expo Go?

Hello Dan, I was able to establish a connection with my device using your video and successfully send and receive data in the "connectToDevice" section. However, it doesn't make sense to work in that section, so after making the necessary changes in the "startStreamingData" section, I made a few modifications to the "onHeartRateUpdate" section according to my needs, but I'm not receiving any data at all, and the program doesn't even pass through the "onHeartRateUpdate" section. Can you please help me? I'm very desperate. :(

Hey Dan, thanks for the video! Trying to set up the application for ios. Logged in to my Apple account, however I get such error: "Authentication with Apple Developer Portal failed! You have no team associated with your Apple account, cannot proceed. (Do you have a paid Apple Developer account?)" Do I need paid membership in order to run for ios?

can i use this method for bluetooth printing with expo?

That is does not working at all Ill use expo and even if I download your code that is not working

more expo, please 🙏

Hi Dan im confused when i start to run in video part 10:27 im getting this error This error is located at: in App (created by withDevTools(App)) in withDevTools(App) in RCTView (created by View) in View (created by AppContainer) in RCTView (created by View) in View (created by AppContainer) in AppContainer in main(RootComponent), js engine: hermes ERROR TypeError: Cannot read property 'createClient' of null

Hi, i followed the video step by step but when i launch my application i get the following error. 'Cannot read property 'createClient' of null, js engine:Hermes, what Can i do ?

Hi Dan. Thank you for your list tutorial videos I have a question My Device have password for Unlock. Now, I unlock it to click on button and it unlock immediately but if I do not have password so can I looping from 000 - 999 to find out correct password of devices is it possible ?

What can I do about event emitter warning?

I did step by step, but on Android it gives me the message: "Render Error null is not an object (evaluating '_BleModule.BleModule.createClient')" Maybe someone has any suggestions?

hey dan, can this work for android platform?

Hello, I have a Xoss heart belt, it has the same uuid, I cloned your git and it still doesn't appear on Bluetooth, could you give me any tips on how it can appear?

Can react-native-ble-plx send modbus data ???

why does not `npx expo run:ios` work for you ?

So you have to prebuild? It sucks because on windows you can only prebuild for android and not ios ...

how I can get UUID and characteristic UUID

What is this VS Code theme?

is there no way to test this in the IOS simulator?

Hey Dan quick question, since @config-plugins/react-native-ble-plx itself sets up the plugin for us, do we still need to copy your plugin setup? Also @config-plugins/react-native-ble-plx itself is depreciated and it sets up everything itself. How does that change things?

When I type this command: npx expo install react-native-ble-plx @config-plugins/react-native-ble-plx I get this error: --- › Installing 2 other packages using npm npm install --save react-native-ble-plx @config-plugins/react-native-ble-plx npm ERR! code ERESOLVE npm ERR! ERESOLVE unable to resolve dependency tree npm ERR! npm ERR! While resolving: expo-ble-app@1.0.0 npm ERR! Found: expo@50.0.14 npm ERR! node_modules/expo npm ERR! expo@"~50.0.14" from the root project npm ERR! npm ERR! Could not resolve dependency: npm ERR! peer expo@"^49" from @config-plugins/react-native-ble-plx@7.0.0 npm ERR! node_modules/@config-plugins/react-native-ble-plx npm ERR! @config-plugins/react-native-ble-plx@"*" from the root project npm ERR! npm ERR! Fix the upstream dependency conflict, or retry npm ERR! this command with --force or --legacy-peer-deps npm ERR! to accept an incorrect (and potentially broken) dependency resolution. --- Do I need to downgrade the Expo version or should it work for the newest version?