What I have read from many documents of Android Developer and lectures that I searched on the internet is: Advertising is sending signals to a broadcasting device so that the device could be found and Broadcasting is scanning the advertising devices to connect/send data.
Is what I understood correct?
Then is it true that BluetoothLeAdvertiser should be implemented first before scanning activity?
I am keep researching on the internet to find information in order to create an app that can broadcast a short word to other nearby devices through BLE.
However, when I was doing research people do not use class LeAdvertiser that was introduced as an example on Android Developer page. Why is it??
As Emil said, broadcaster/advertiser is the device that sends out BLE adverts. Broadly speaking, there are 4 main (GAP) roles in Bluetooth Low Energy:-
Broadcaster - A devices that just advertises data.
Peripheral - A device that advertises data but can be connected to by remote devices as well.
Observer - A device that just scans for data.
Central - A device that can scan for data as well as connect to them.
When BLE was first introduced, beacons/sensors (e.g. Heart Rate, Thermometer) occupied the first two categories and phones/computers occupied the other two. However, BLE has since evolved and a lot of devices now support all four roles and a device can operate in one or more roles at the same time.
And yes, if you want your device to be found by other observers/scanners, then you should first use LeAdvertiser in order to send out BLE adverts. Have a look at the links below that show how this is used:-
How to advertise Android as a BLE peripheral
Sample Bluetooth LE GATT server
BLE: send data to iOS from Android
Related
I am searching for some way that can connect to Bluetooth devices without pairing. Or at least make a connection first and then it does not need to be established all the time. Like how wearable devices work (i.e. mi band 6 or Huawei band 6). Can someone please guide me towards some helpful demo or documentation for this somewhere?
Also, I was wondering how was the security managed since my Bluetooth is always on to communicate to the wearable device. Though, turning off discoverability does not seem to create any issues in order to communicate with the device.
Most wearables nowadays use Bluetooth Low Energy (BLE), and with BLE you don't need to pair in order to exchange data - i.e. only a connection is needed. That being said, it is recommended to pair as the data exchanged between the wearable device and the phone will be encrypted, in addition to some other benefits in terms of privacy and security, Have a look at the links below that will go over connection/pairing in more detail:-
Should one create a bond with BLE device
The Ultimate Guide to Android Bluetooth Low Energy
Making Android BLE work
Currently, I am developing an app which is communicating with one BLE Hardware which is receiving commands and responding back the command response. To Simulate hardware, We have developed one iOS Simulator app, which is working in Peripheral and responding back on requested command. But Somehow, As and when I try to write to the write characteristics, I got the status = BluetoothGatt .GATT_REQUEST_NOT_SUPPORTED in the onCharacteristicWrite callback. But somehow, I came to know that we need to implement the Central and Peripheral roles into Android app.
But I am still not sure, Do we need to implement Peripheral role as well to send and receive data in multiple packets.
I am developing the app using following nice blog post:
- https://medium.com/#avigezerit/bluetooth-low-energy-on-android-22bc7310387a
- https://android.jlelse.eu/android-bluetooth-low-energy-communication-simplified-d4fc67d3d26e
- https://www.bignerdranch.com/blog/bluetooth-low-energy-on-android-part-2/
And using following repo as learning point of view:
- https://github.com/bignerdranch/android-bluetooth-testbed/tree/a/android-ble-part-3
Thanks in advance!
Typically your phone app is the central and it communicates with a peripheral device over Bluetooth. If you want to send data to the peripheral, you can write a characteristic in the phone app, given writing is enabled for that characteristic. Your central can get data from the peripheral in 2 ways: it can either read a characteristic (if it's enabled) from the peripheral or receive notifications from the peripheral (if it's enabled). So if all you have is a central (phone app) and a peripheral (some kind of Bluetooth device) and you want to send data back and forth, you don't need to have both central and peripheral roles in the phone app. If you have some special stuff going on, it might be different for you, I don't know. I'm talking about a typical setup.
If you want to send commands to the peripheral, you could write those commands to a characteristic. The peripheral could in turn respond with notifications. This is basically the way I develop a Bluetooth solution, but it can be different depending what you want to achieve.
It takes two devices to communicate with each other.
Device A:
It will be Peripheral device which will be advertising the data. i.e.: Beacons, BLE Hardware
Device B:
It will be Central device which will send request for read,write. i.e.: Mobile
Setup for Device A:
If you don't have Peripheral, there is a way to make your android mobile to act like a Peripheral if your device is supporting that advance feature.
So before beginning, you may simply check that by using following app:
https://play.google.com/store/apps/details?id=com.kyriakosalexandrou.bluetoothsupportcheck
To make your device act like Peripheral, you may install following app which simply simulates the GATT and advertising:
https://play.google.com/store/apps/details?id=com.ble.peripheral.sim
Important: Setup service and characteristics based on your requirements, make sure characteristic is write enabled if you want write data on it.
I had been wondering how wireless earbuds work and came across this image. I do not know how to replicate what is shown in the following image and would like to learn how to do it.
My end goal is to be able to have the smartphone connect to a device, while still being able to play music to a Bluetooth Headphone. I read into BLE 4.1 mesh and I am not sure if that would help either.
I have made images for the possible ways the multiple devices could communicate but I don't have enough reputation to attach the xD. I will try my best to describe them.
1) All devices manage to simultaneously communication with the smartphone.
2) All devices connect to a hub which relays data to the smartphone.
3) One device is the hub itself and relays data for all other devices while sending its own data.
4) The devices relay information for each other till the smartphone receives the data it called for.
5) Another possibility is to have a mesh structure where the devices relay all messages broadcast-ed over the network until the device for which the message is meant for, receives it.
I hope to make a project where a Bluetooth device I make does not hinder the user from connecting and using other Bluetooth devices simultaneously.
Thanks for reading and I look forward to any and all responses.
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You need to consider few things first.
Since version 4.0 Bluetooth specification contains "Classic
Bluetooth, Bluetooth high speed and Bluetooth low energy (BLE)
protocols."
Bluetooth Classic provides profiles like A2DP, AVRCP that
are usually implemented by Bluetooth earbuds or speakers.
BLE on the other hand communicates using GATT (a general specification for
sending and receiving short pieces of data known as attributes over a
low energy link).
BLE is not designed to handle high bandwidth scenarios like Audio.
Now getting to a point
You can have a smartphone connected to your earbuds with A2DP profile
and simultaneously connected to several BLE devices.
One or more of these BLE devices can realize mesh connectivity
I'm developing an app to communicate with a BLE device (Sensor puck from Silicon labs) and get whatever it is broadcasting.
I have NO experience in developing any sort of Bluetooth application using Android.
Do I need to manually pair it to the BLE device? I downloaded Sensor puck app from Play store, it automatically started to read from the device. I don't understand how since I didn't pair it.
Do I need specific API to communicate with the device? Is it like, I connect to the device and unpack the data which the device is broadcasting?
Any other information related to BLE application development would help.
Thank you.
PS: I can't use the app from the play store as I need the data from the device for some other processing.
I have a little experience with developing BLE apps.
Do I need to manually pair it to the BLE device?
I haven't encountered use case where I needed to pair mobile device with BLE device. Basically, you can communicate with BLE devices without pairing with them. BLE devices constantly emit signals and you can read these signals. Usually, from the emitted signals, you can read name of the device (or producer name), MAC address, RSSI signal from which you can compute distance from your mobile device to BLE device. Some BLE devices emit other information like temperature read from their sensors, etc. You can read information from more than one BLE device during the single scan.
Do I need specific API to communicate with the device?
Google provides API, which you can use to communicate with BLE devices. You can read more about it at: http://developer.android.com/guide/topics/connectivity/bluetooth-le.html. You can also use some third-party libraries allowing to communicate with BLE devices. Most of them are dedicated to so called Beacons, which are simple, tiny BLE devices.
Exemplary APIs for BLE Beacons:
Estimote
Kontakt.io
AltBeacon
ReactiveBeacons - this is open-source project, which I'm currently developing, so if you have any questions regarding it, you can ask me directly
Other projects:
Android Bluetooth Demo - this is very good and simple project, which can help you to understand how to use BLE API provided in Android SDK
Other information:
To communicate with BLE devices, of course, you need to have Bluetooth enabled on your device, but regardless of this permission, you also need to have Location enabled on your device and added location permission to your app. I guess it's done due to the fact, that you can use BLE devices for creating micro-location services.
I gathered some references concerning BLE for myself. You can check them here: https://github.com/pwittchen/ReactiveBeacons#references and maybe they will be useful for you as well.
Regards,
Piotr
it might be too late, but it also might be helpful for other users. So Sensor Puck works like a simple beacon and it doesn't require any pairing. You just have to scan all bluetooth devices nerby and verify received ScanRecord object. You don't have to use any specific libs or API, Anroid sdk contain all necessary api for such case (please see BluetoothAdapter startScan, startLeScan, etc). Also you can find an example how to parse raw data in my demo project https://github.com/alexeyosminin/sensor_puck_demo
I'm not a developer but I'm curious about the connectivity options between smartphones.
Looks like BLE is the only technology that is available on both Android and ios that could make an connection possible in the foreground, but is able to scan in the background?
If I walked around with my phone in the pocket, could it scan in intervalls for other devices`UUIDs/mac addresses and save the data realibly without the process being shut down after a while?
the app would have to work between Android phones, ios Devices,
and Android phones-ios Devices.
I dont want a stable connection. I'm only speaking about gathering UUIDs and mac adresses in the background. whichever is more suitable to uniquely identify a device.
Thanks in advance.
iOS devices with BLE support can act as the peripheral and/or the central role. The peripheral advertises its services, and the central discovers them (via scanning). You need Android 5.0+ to support peripheral mode.
Once a central discovers a peripheral, the central can obtain advertisement details from it, including a unique peripheral ID. This is similar to a MAC address, though some peripherals randomly generate these IDs.
In general, an iOS or Android device acts in the central role and it doesn't advertise anything. There is nothing to discover. However, you could write an app that acts as both a peripheral and a central.
On iOS, your app can perform both BLE roles in the background (your app doesn't need to be in the foreground).
You would want to do background tasks responsibly as both advertising and scanning require the radio, which uses a significant amount of power (drains the battery).
There are many issues with the current BLE stack on Android (e.g. using WIFI and BLE at the same time because they share the radio). The BLE API first became available for Android with 4.2.
The iPhone 4s and later has BLE with the API first available in iOS 6.