First of all, I spent more than 10 hours of searching for a solution on Google...
I'm working on an app for athletes, doing sports like running or cycling. It should be based on Bluetooth LowEnergy. I have a real heartbeat sensor device to work with and there is the problem.
The Problem is that the sensor doesn't always work if I want to test the scan or something. My phone isn't able to find the sensor all the time, it works just one out of 30 attempts. So what I want to ask is, is there a way to simulate a BLE sensor device like a heartbeat-sensor (over the PC for example)?
I have devices running 4.3 and higher (Samsung, LG and a Sony smartphone), so that shouldn't be the problem. Furthermore I already had a success in connecting to a BLE-Heartbeat sensor, but for testing it's really hard to work with a real sensor device (because of the problem that I can't find it all the time).
Hope my problem is understandable and somebody can help me!
As #bobh says, an old iOS device running a custom app would work as a test BLE peripheral. And I bought an iPod Touch for just that purpose.
Unfortunately Android has only introduced native BLE support as of 4.3 and won't yet work in "peripheral" mode.
There are cheaper alternatives too. There are many BLE dev kits out there:
https://developer.bluetooth.org/DevelopmentResources/DevelopmentPlatforms/Pages/Development-Platforms.aspx
If you don't want to mess around with wires and breadboards then you could try BlueGiga's programmable BLE USB dongle. It's about 26 bucks and they have example code for the Heart Rate Profile so your life would be very easy:
http://www.bluegiga.com/en-US/products/bluetooth-4.0-modules/bled112-bluetooth-smart-dongle/
If you have an old iPhone 4S or iPad 3 and are an iPhone dev (or jailbroken device), you can prog it to be a test device https://github.com/AttackPattern/BlueSim
And tweek the sensor characteristics.
Works on a Mac with old Xcode 5 and BLE dongle but requires some work.
github
Related
we are developing an Android app which can connect to multiple heart rate sensors simultaneoulsy via Bluetooth Low Energy.
We have an implementation which is working quite well, so the code is not the problem.
What drives us crazy is the limitation of parallel BLE-connections which seems to be different from device to device.
We have a few test devices here: Motorola MotoE and MotoG, a Samsung Galaxy Tab A and an HTC Nexus 9. All of them are running Android 5 or 6, original vendor versions. None of them is able to connect to more than 7 BLE HR sensors simultaneously.
Then I have tested with my private Samsung Galaxy S4, which is rooted and has Cyanogen CM12 installed. With this device I can easily connect to 12 HR sensors simultaneously which is the number we want to achieve with our app.
I have tested this both with our own app implementation and with the Nordic Semiconductor nRF Master Control Panel which I think is a pretty good generic BLE app: https://play.google.com/store/apps/details?id=no.nordicsemi.android.mcp&hl=de
When I try to connect the app to a 7th BLE sensor on any of our devices, the ADB output prints the following error message:
E/BluetoothLeBasicConn: Connection state changing error: 133
I did some pretty intensive googling about that whole problem, but most of the results I've found were quite old. Some people said, that the limitation came from the Bluetooth Chipset itself, others said it was a software limitation through Android.
Could you help me to find out, where the limitation is coming from?
If it is the chipset, then I would like to know, which devices we should use for supporting as many parallel connections as possible. Sadly it is very hard to find out which Bluetooth chipset is built in the different devices. Hardly any of the hardware specs I found tell anything about this.
If the limitation comes from software side, can we change it somehow without rooting phones or install modded OS?
Thank you very much!
In case that you are still interested in it. The limit comes from
BTA_GATTC_CONN_MAX (hardcoded in android)
Which is set to:
4 on Android 4.3 and
7 on Android 4.4
There is by the way also a limit on the amount of characteristics for which you can activate notifications. (BTA_GATTC_NOTIF_REG_MAX)
which is:
4 on Android 4.3,
7 on Android 4.4 and
15 on Android 5.0
How many devices can be connected to at one time via Bluetooth using the BLE firmware on Android?
A search of the Android Bluetooth Firmware source shows the following:
Max concurrent active synchronous connections (BTA_GATTC_CONN_MAX):
4 on Android 4.3
7 on Android 4.4+
Max concurrent active notifications (BTA_GATTC_NOTIF_REG_MAX):
4 on Android 4.3
7 on Android 4.4
15 on Android 5.0+
As a comparison my experience with iOS is that 8 devices can be connected at at time.
I tried connecting more than 7 devices the other day on Android 7.1 and Bluetooth stopped responding. Starting and stopping didn't help; the only thing that fixed it was restarting the device.
After working with several apps that connect to 4+ devices I can say from experience that these numbers are theoretical. Depending on each individual device and its hardware you'll have an easier or harder time connecting to and maintaining a connection to the maximum number of BLE devices.
Follow Bluetooth at Wikipedia,
A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum.
You need know Master/Slave in Bluetooth first.
I think the good answer depend on your aim.
You're right when you know "can communicate with how many devices" depend on Hardware (Bluetooth Chip).
Bluetooth chip on Apple iPhone 4, 5 or Samsung Galaxy S3, S4 ... totally different with Basic Bluetooth Chip.
In my case :
I'm working with Firmware side related to BLE.
His peripheral device has used Basic Bluetooth Chip since it did not has enough memory to store many capacities as many features, likes Bluetooth chip on Apple iPhone 4, 5 or Samsung Galaxy S3, S4 ....
Therefore, his peripheral device only paired with one device in one time.
Thanks,
Both of the answers here are wanting so I thought I should add one:
There are connection limitations built in to the different BLE hardware. I think the lowest I've encountered is 3 connections at once and the highest was about 12-13 connections. These were limitations due to the design of the hardware and had nothing to do with the OS being used, though. Usually the limitation is due to the fact that the hardware has to keep track of certain data and there's a limited amount of memory in the hardware.
So, I don't know specifically for Android, but it doesn't make much sense for a limitation to be imposed at the OS level. Likely when you try to make a connection, and you've reached the limit due to the hardware, you should receive some sort of error/exception preventing the new connection. I think there's actually a "connection limit" error in Bluetooth, but some hardware gives other exceptions like "out of resources". Again, I'm not sure how that gets reflected on the Android level.
I come into BLE development without any knowledge in Classic Bluetooth development and I really don't know what "pair" means in BLE. Isn't that something only exists in Classic Bluetooth?
If you are talking about connection, when Android 4.3 first came out I made a few test on the SDK on Nexus 7 2013. The maximum number of devices it can connect is 4. I didn't test if this number changes in 4.4, but I can confirm it will not be anything less than 4.
For every system, be it any firmware or OS like Android or iOS, there is a configured maximum concurrent connection limit. But in reality the connection parameters of each connection play a very important role in determining weather or not the system will be able to achieve that many concurrent connections.
For example, if the configure connection limit is 4 then the system can not have more than 4 concurrent connections. But if all of the connected devices are demanding a higher connection interval(say a 50mS connection interval) then the system may not be able to support all of them. This results in either some of the connections dropping out or not being able to connect entirely. But if the connection parameters are a bit relaxed(say a 1sec connection interval) then all the connections can be serviced properly.
I am currently working on an Android project that requires Bluetooth Low Energy Peripheral mode. As of now, just targeting the Galaxy S4 with 4.2.2 on it Samsung BLE SDK at http://developer.samsung.com/ble
I followed their API docs and programming guide very closely, however broadcasting characteristics or services over Bluetooth Low Energy just doesn't seem to work. Has anyone else had any luck with getting this to work yet? If so, any help would be greatly appreciated!
Thanks a lot.
Because Samsung BLE SDK only supports the central role, “advertising” a service as a central server means sitting their quietly, only revealing (or “advertising”) its service characteristics to another device in peripheral mode after a connection is already established. This connection establishment requires another device to do the actual radio advertising first. Samsung’s SDK isn’t going to do it.
What we need is an Android BLE API that allows creation of a peripheral server. Lots of folks were hoping that peripheral role support would be added in 4.4, but it wasn’t. Maybe we can hope for its addition in Android 4.5 or 5.0. There is a feature request asking for this. Add your name to the list!
Source
I am having the exact same issue. I can discover BLE devices and get their rssi values, but when I try to discover services or connect, I never receive a callback. I am using a Verizon Galaxy S4 running 4.2.2. I am using the Samsung BLE SDK 2.0. Apparently some heart rate monitors are working, but I get nothing using my ez430-rf256x TI development kit. I've tried the Keyfob demo and Heart Rate Profile demo in the Bluetopia v1.3 sdk.
Phones/tablets/pc's support(usually) Bluetooth dual mode chip. According to Bluetooth specification dual mode devices can't be a peripheral, but single mode devices do.
I am developing a very simple App for a final year Degree project, It's a simple Proximity Application where once a Bluetooth device moves beyond the range, it creates a supervisor timeout which triggers an alarm.
My main problem is actually trying to make a connection with a TI CC2540 (KeyFob). I have loaded the demo software as provided by TI, all works well with Btool etc. and I am using a HTC Desire C (ICS, BT4.0), which does pair with the CC2540. I have put together an APP, but have recently downloaded the BTChat Example from the Android SDK. The Example App recognises the Keyfob, and even gets the correct Mac Address but as soon as I try to connect with it, it doesn't connect (Establish a Link). I have carried out a lot of research and thought my problem may lie in the area of the UUID (128) but I am unable to find the correct UUID for the device. Incidentally I have used the common one from the Android Dev Website, plus derivatives but with no success.
I eventually found an existing App for an Iphone (Bluetooth Smart Scanner) which did recognise my device but gave a 'null' response for the UUID.
I am at a loss about where to go, could anybody point me in the right direction?
best regards Wayne
According to specification at gsmarena, the HTC Desire C may actually only have Bluetooth 3.0, so not 4.0 "low energy" (HTC's own website does not even mention bluetooth -- see HTC website specs ?). Android SDK does not support bluetooth low energy either... so you may be out of luck. There is somewhat supported Broadcom stack, and Motorola has their own stack... Samsung Galaxy S3 may be hacked to work by reverse engineering existing apps...
If you need a phone which does support Bluetooth LE, Motorola XT885 will do if you download the Motorola ICS_R2 Android SDK add-on. See this post: Motorola BLE API
In my App I need to connect a smartphone with an 4.0 low power Bluetooth-module. Then the module sends frequenly data to the phone.
Do you know some good tutorials for programming Bluetooth connection
with Android?
Can you give me some links where the basics of Bluetooth are
explained? (german if possible)
How can I test it? (I have to programm the Bluetooth device too
and it's not finished jet)
Google havn't understood that sometimes they have to actually create and DRIVE something themselves, not just piggybacking on open source stuff and marketing it as their own.
Unfortunately there are no standardised BT 4.0. Low Energy API's for Android yet. Maybe Google just decided to only go for NFC for Google Wallet or something and then let BLE die. (We really need BOTH!)
Broadcom tried to make an open source API but somehow (maybe Broadcom wanted money from them?) no phones included the ".so" file in their Android build so this API is useless.
TI and Motorola made another API for the RAZR series running on old Android 2.3.3 or something. This actually works but Motorola removed the documentation and source-code from their site.
HTC ONE X+ and newer HTC phones will support a new API "soon" with special HTC libraries according to HTC. (At least it seems they are doing something)
Samsung Galaxy S3 have some "secret" API's that some people can use for discovering devices, scanning services and characteristics (there is an app in google play "semilink Bluetooth Smart Scanner" which on the Galaxy S3 can do those things).
Google asked Broadcom to make a replacement for Bluez in Android 4.2. Unfortunately this release broke a lot of functionality and peripheral compatibility. Maybe because one or more of Wifi/GPS/Bluetooth Classic/Bluetooth Low Energy shares the same HW resources but the drivers doesn't handle that very well. Lot's of people got problems with the newest Android Bluetooth functionality.
So I would expect Broadcom to focus on fixing the mess and THEN with Google move on to add Bluetooth 4.0. Low Energy. Google have said "Low Energy is the next BIG thing we will integrate". At least 1 year too late.
Personally I had to buy an iPhone4S and iPad retina to get platforms which supports low energy. With those we could finish the BLE peripheral sw and get the protocols working. Now we are waiting for Google and Broadcom to clean up the mess. Hopefully with some backwards compatibility so all the old phones with BT4.0. capable chipsets will also open up to the wonderful world of coincell battery driven peripherals ;-) (got to dream).
In reality we must wait for HTC to release their APIs and for Google to choose/drive the standard API.
Windows Phone 8 was supposed to get BLE but it has been postponed for an update. (Lumia 920 is certified but without API's (AGAIN!!) we developers are helpless)
There are nice GATT API's for Windows 8 as well as for MAC "OS"x.
You really should invest in the TI BLE development kit which costs like $50-$100 for a dongle which can be used for BLE sniffing. It comes SOOO handy when you develop your BLE Peripheral SW.