Bluetooth Low Energy is a wireless protocol introduced in 2010 to enable quick and easy connection between devices and smartphones. It also allows creating device to device connections without smartphones, but has been used to connect appcessories to iPhones, for example. BLE can connect:
Although Bluetooth Classic and BLE share some common components, they are not compatible. Rather, they work side by side. A BLE radio can't connect to a Bluetooth radio unless that Bluetooth radio supports BLE (called Dual Mode).
Beacons are BLE devices that transmit standard packets. Devices that are nearby like smartphones can receive these packets and trigger events. For example, Beacons are used in retail stores to help the user interact and provide custom offers.
BLE has several advantages compared to Bluetooth Classic. It is much lower power, up to 100x lower consumption, can connect quickly, has wide support, and can communicate data to iPhones without the need to create an MFI compatible device.
BLE can be used from a few feet of range to over a 1km, depending on design and features used, antenna, RF design and environmental conditions.
BLE uses a Master (Central) and Slave(Peripheral) topology where a Central can connect to multiple peripherals. Centrals can connect to multiple devices and it's possible to connect 20 peripherals to one Central. There are limitations depending on memory, timing and other aspects which are application specific, but the limit is typically practical in nature. A device can be a Central and Peripheral device simultaneously as well.
Because BLE is a protocol designed for low power, BLE based products can use anything from Coin Cells, Alkaline, Lithium Ion or practically any power source. The current draw in the microamps make it also possible to use energy harvesting.
BLE can achieve a data rate slightly over 1.2Mb/s in practice, but the actual data rate depends on factors like the signal level, interference, radio PHY, and implementation.
BLE radios are RF transceivers, so you will need to get FCC (US) IC (Canada), CE (Europe) or applicable certification for the countries where the device will be used or sold. You will also need to get an End Listing with the Bluetooth Special Interest Group.
Before the adoption Bluetooth 5.2 specification, BLE was limited in its ability to stream audio. This was usually done using custom implementations The audio would be compressed to reduce the data rate and usually didn't need real time low latency. For example, TV Voice Remotes commonly use BLE to transmit the request when you press the button. However, streaming quality audio was not possible. With the introduction of Bluetooth 5.2, Audio streaming over BLE is possible, although the specifications are still in progress at the time of this writing.
Bluetooth 5.0 is a Bluetooth Specification adopted which introduced several new features and capabilities to increase the speed and throughput of BLE.
Bluetooth 5.0 is a Bluetooth Specification adopted which introduced primarily the Location capability, allowing devices to use Angle of Arrival (AoA) or Angle of Departure (AoD) to locate devices physically and enable Real Time Location Services (RTLS).
Bluetooth 5.0 is a Bluetooth Specification adopted which introduced LE Audio, the ability to stream audio over Bluetooth LE (previously supported only by Bluetooth Classic), as well as GATT enhancements and several other improvements.
If your main application is audio or voice, Bluetooth Classic is still the best option because it's widely supported. For example, a Car Hands Free system doesn't support BLE and you need Bluetooth Classic. BLE can augment products by letting you configure them using an app, for example.
In most cases yes. Talking to a BLE device is usually done via an app that's programmed to do so. The exception is if you're not communicating with Smartphones or tablets and are using embedded systems.
Bluetooth Classic is used to connect headsets, speakers and other audio devices to smartphones and tablets. BLE is used mainly to exchanged data. Bluetooth Classic can also exchange data, but BLE is quickly replacing it because it's lower power, lower cost and faster to connect. Bluetooth Classic can be used to connect many devices, even if it's not as good as BLE
The Bluetooth specification provides for security using authentication and encryption which protects data. This security features need to be enabled. Devices before Bluetooth 4.2 are generally insecure because of the algorithms used.