I have established a connection between an nRF52 which has the advertising interval set at 20ms and iOS software, but the packages are only received every second roughly. Has anyone had this issue before/knows any tricks to speed up the frequency? Many thanks.
Its depending on nRF52 or other peripheral advertising interval in firmware. Also depends on data/packets transfer speed/distance.
If there is write characteristic available on peripheral for set time, then send/write values and speed up for this. Some device has this property for advertising interval time set but iOS/Android app.
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I want to send some sensor data over BLE to multiple nodes.
I thought of changing advertising data at 4Hz. Can it be done?
Yes! It is a common approach to use a BLE beacon packet to advertise sensor data. A few points:
Embedded BLE platforms typically allow advertising at a minimum of 10Hz, and let you change the advertisement between transmissions. I have done this on the Nordic 52x chips, but hopefully STM32 supports it as well.
BLE 4.0 advertising packets are limited to 23 usable data bytes, but you typically need to reserve a few to indicate it is "your" transmission. There are significant further restrictions if you intend to use iOS devices to scan the transmissions. If using Android, Linux, or other embedded system scanners you can use nearly the full 23 bytes.
Keep in mind that anybody in radio range can scan for these advertisements and read the data. Make sure the sensor data are not sensitive enough to warrant a security layer.
Is there any way to retrieve a battery voltage from my iBeacon?
Maybe adding a byte somewhere in the advertising packet to present the value of the battery.
There is no standard way to do this with iBeacon. Other formats like AltBeacon and Eddystone-TLM do include a data byte to transmit the battery level.
Many hardware beacons support interleaving multiple beacon transmissions from the same hardware device, so even if you need iBeacon, you could still transmit the battery level in one of these other formats.
I'm trying to use a WiPy board as a BLE scanner and we're detecting some extrange behaviours on radius Network Dot beacons.
We are trying with several beacon manufacturers, all emiting as iBeacon with an advertising interval of 100ms (10 per second). In the board we detected every second at least 4-5 advertising packets of this beacons, but most of the times 0 or 1 of the radius beacon dot.
We've tried with both altBeacon or iBeacon configuration and the results are similar.
This is a screenshot of the configuration with the RadBeacon app:
Are we configuring something wrong or are the beacons having an unexpected behaviour?
Not 100% of advertising packets send out by a Bluetooth LE device will be detected by receiving devices. The actual percentage received depends on a number of factors including:
Transmitter power level
Distance between the two devices
Radio noise in the area
Bluetooth radio congestion
Antennas on both transmitter and receiver
Orientation of antennas
Under good conditions (close range, high transmitter power), I typically see 80-90% of packets get detected by Android and iOS devices which allow you to easily count individual BLE packets.
Since your detection rate is much lower, you may want to try a number of things:
Increase your transmitter power level from -18 dBm to 3 dBm. Having the weakest power output configured is the most likely cause of your issue.
Bring your transmitter and receiver closer together.
If the above two suggestions don't help, I would use an independent tool such as an Android phone to actually count the number of BLE packets detected. I have an bare-bones app you can run on Android to do this here, but you'll need a copy of Android Studio to build and run it.
I'm trying to establish a bluetooth low energy link between a custom pcb and a mobile device. The application requires a tablet device and a BLE link that operates as fast as possible.
Since the BLE Speed is main defined by the allowed number of packages per connection interval and the minimal connection interval I'm trying to find a tablet with those capabilitys.
I have been searching a lot and just found the following information:
IOS device are stuck with a minimal connection interval of 30ms
Android devices are technically able to deliver 6 packets each 7.5ms, but usually it wont settle for anything below 20ms.
I find it very hard to get solid information on that topic. I found nothing about Windows Tablets and Tizen Tablets.
Does anyone have information about that topic?
You see, the standard Android bluetooth code is (with sometimes small adjustments by each manufacturers) the same on every device and the bluetooth controllers available on the market tend to only send 3-6 packets each connection event if the min/max connection event length is set to 0, which it is by default in Android's code.
Is it possible for you to work with AOSP, i.e. modify the Android source code? If so you could change the HCI call where a connection is created or connection parameters are updated. Change the min/max connection event length (Minimum_CE_Length and Maximum_CE_Length) to some large value and you will then be able to write many many packets in one connection event regardless of connection interval.
The relevant places in the code are https://android.googlesource.com/platform/system/bt/+/d35bb40dd563e7f37df0a2fa9c0f61d0958b9601/stack/l2cap/l2c_ble.c#945 and https://android.googlesource.com/platform/system/bt/+/488005b16bd2552ce7e5f9c1e1b3d4072397fc26/stack/btm/btm_ble_bgconn.cc#394.
My requirement is as follows:
I need to send Proximity Sensor (Reed Switches/Magnetic Sensor) reading (On/Off) from two Input Pins to a central PC.
I need to use coin cell. So basically the app should be in sleep mode and once there is any interrupt on any of these two pins it should wake up to send its state to the central PC.
I have DA18450 chip and development board (murata ZY type) with me.
Dialog Semiconductor 18450
Murata Bluetooth Smart Development Board
I am a beginner to bluetooth technology and started reading about it just a week back.
Could someone guide me about the most apt Profile/Service suitable for my application?
If you want the device to actually sleep then it'd probably be best for it to just transmit data via advertising packets when the device awakens. Otherwise you have to maintain a connection which requires staying awake at some level. However, advertising packets are broadcast and the device can't know if anything received those packets (you could have it broadcast several times for a fixed period of time or have it constantly broadcast while the proximity alert is valid). Also, on the receiving end, with no connection there's no way of knowing the transmitting device is even there when nothing is being transmitted.
The advertising packets have a section for limited information and that's where you'd transmit data if you don't want to establish a connection.