I am programming Nordic devices as BLE peripherals. My smartphone acts as BLE central. I would like to transmit data from my smartphone to all the devices one after the other.
Is it possible to compute the time that the smartphone requires to jump from one connection to the other?
Knowing the BLE throughput and the time needed to jump from one connection to the next one, I could compute the time that the whole process would take. Nothe that I do not want to connect all the devices at the same time but one after the other.
Best regards
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i want to know the fundamental difference between BLE and Classic Bluetooth and why exactly is BLE low power?
There are quite a few differences between Bluetooth Classic and Bluetooth Low Energy including:
Classic Bluetooth operates on 79 frequency channels, whereas BLE uses only 40.
Classic Bluetooth has a higher throughput than BLE, although the gap is becoming narrower with newer versions of BLE.
A classic Bluetooth device can only be connected to 7 other devices, there is no theoretical maximum to BLE.
The two use different mechanisms for broadcasting/connection. Classic only devices cannot find or connect to BLE only devices and vice versa.
The list goes on beyond the above to the point that it is more common to assume that they are two protocols only sharing a few technical similarities and the same standardisation body (The Bluetooth SIG).
As to what makes BLE low power, this lies in the duty cycle of the protocol. BLE devices sleep for most of the time they are not in operation, and only wake up to send bursts of data and then go back to sleep. Of course this depends on the use case; if an application continuously sends BLE data then there will be fewer sleep intervals and therefore the power consumption will match that of classic Bluetooth.
For more references regarding this question, please see the list below:
4 Key Differences between Classic Bluetooth and BLE
The difference between Classic Bluetooth and BLE
Bluetooth vs Bluetooth Low Energy (BLE)
Bluetooth vs BLE
Can a Bluetooth LE powered device discover a classic Bluetooth device and vice-versa?
I hope this helps.
I am pretty new to IoT and BLE. What I want to achieve is to write on GATT characteristic of at least 100 peripheral devices simultaneously or in a very short period of time(i.e. less than 100ms). Currently my peripherals are Ble nano (nRF51822) with custom GATT service running on them. I am using my Mac as central BLE. I am using Node.js and noble to implement the central. I want to know if such thing is possible at all and if possible, please link me to an example code. :)
You should note that Bluetooth chips for computers are usually (quite arbitrarily) limited to only a few simultaneous connections. Common values are between 3 and 14. Even if you connect a few at a time, send the characteristic value, disconnect and then connect next devices it would be impossible to do this within 100 ms. If you want to send the same data to everyone you should instead let your computer advertise and the nrf devices scan. That way you broadcast the data instead.
I'm writing a Bluetooth Low Energy library. For now, it will only run on Linux (and with Bluez 5.41+).
I'd like to have tests that can be run on any computer with BLE support and test the entire stack (application, host and controller), without requiring extra hardware (another BLE-capable device). Requiring extra hardware is a great way of making sure the tests won't be run more than once in a blue moon.
For that end, I'd like to use my computer to connect to itself (as both a peripheral and central) during the tests. It seems like this should be possible, since I can be connected at the same time as peripheral and central to other devices. But advertisements from my own computer never show up on (my own computer's) BLE scans.
Is it all possible to have the computer connect to itself in this way?
No, not if you only have one Bluetooth controller.
The reason is that radio peripherals can only transmit OR receive in a given time moment.
I couldn't find a clear explanation what is Bluetooth le multi advertising.
For example, in Specification of the Bluetooth System, I see only
description of BLE advertising but not multi advertising.
What the difference between BLE advertising and multi advertising?
Thanks
LE Multi advertising refers to a specific offload (non bluetooth specification) feature that has been implemented in the Android releases by Google, starting from the L release.
What multi advertising means is, that your Android phone or a device with Android stack, can enable multiple advertisement trains at the same time. For instance, one specific app can set certain advertisement data (example supported services etc.), advertisement parameters and enable advertisement, and so can N number of other apps, on the same device.
At the hardware level (or physical layer), these advertisement trains are interleaved between the three advertisement channels (37, 38, 39) and thus your phone behaves as multiple peripheral devices at the same time. All these advertisement trains also have a separate Random private address, so they are seen distinctly by the remote scanner.
Bluetooth Smart has two ways of communicating. The first one is using advertisements, where a BLE peripheral device broadcasts packets to every device around it. The receiving device can then act on this information or connect to receive more information. The second way to communicate is to receive packets using a connection, where both the peripheral and central send packets. We will focus on advertisement for several reasons:
You can’t create a connection between two devices without using advertisements. Defining the data and format of advertisement packets is usually the first thing you work on when developing a BLE device.
A large number of BLE products sleep most of the time, waking up only to advertise and connect when needed. This means advertisements have a big impact on power consumption.
Users want responsive products, and the advertising interval is critical in quick connections.
Advertising is by design unidirectional. A Central device can’t send any data to the Peripheral device without a connection. But a single peripheral can advertise to multiple masters in the area.
ref:http://www.argenox.com/bluetooth-low-energy-ble-v4-0-development/library/a-ble-advertising-primer/
I have an android phone and I want it to communicate with 10 bluetooth modules, not simultaneously. I know that a master device can have 7 slaves for bluetooth connection. does it mean "pairing"?
The question is can I have my phone paired with 10 bluetooth devices? Then send them data seperately?
There is no set limit on the number of pairings possible for a device, except for any limitations made by the platform or bluetooth software stack (eg. limited storage).
does it mean "pairing"?
Bluetooth pairing and connecting are two separate operations.
When two Bluetooth devices pair, they will exchange Bluetooth addresses and encryption keys. If pairing is successful, it allows the devices to connect to each other at a later time.
When two bluetooth devices connect, the profiles are established (a2dp if a speaker, hfp if headset, etc), and they can communicate.
Sometimes there is confusion between pairing and connecting since most smartphones automatically connect after detecting a successful pairing.
Pairing is just done once, typically when you buy a Bluetooth product. Connection is done whenever you use the product.
The question is can I have my phone paired with 10 bluetooth devices?
Then send them data seperately?
As mentioned in the other answer, the maximum number of paired devices is platform dependent, it varies from product to product, but there is no set limit. The maximum number of connected devices (that you could send/receive data concurrently to) is 7 according to the Bluetooth specification.