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Bluetooth Low Energy Technology

During 2011, Bluetooth v4.0 with the hallmark feature low energy technology entered the market. Bluetooth low energy technology is especially well suited for sensors, actuators and other small devices that requires extremely low power consumption.

Bluetooth Low Energy Technology Facts

Bluetooth low energy technology offers the following features in demanding industrial and medical applications:

  • High numbers of communication nodes with limited latency requirements.
  • Very low power consumption.
  • Robustness equal to Classic Bluetooth technology.
  • Good real-time features (if a small number of nodes are connected).
  • Very short wake-up / connection time.

Go here to learn more about the differences between Bluetooth low energy technology and Classic Bluetooth technology.

iPhone and Bluetooth low energy demo with connectBlue Bluetooth low energy platform module OLP425

Demo Video: connectBlue Low Energy Platform Module OLP425

To get an idea of the possibilities with Bluetooth low energy technology in the connectBlue Bluetooth low energy platform module OLP425, view this demonstration that shows the use of a tailored app on a standard iPhone 4S (that has Bluetooth v4.0 which features Bluetooth low energy technology).

Bluetooth low energy demo with connectBlue Low Energy Serial Port Service using a computer, a robot, an iPhone and the connectBlue modules OBS421, OLS246 and OLP425.

Demo Video: connectBlue Low Energy Serial Port Service

To get an idea of the possibilities with Bluetooth low energy technology, view this demonstration of the connectBlue Low Energy Serial Port Service using a standard iPhone 4S, a computer, a robot and the connectBlue modules OBS421, OLS426 and OLP425.

What is the Difference Between Bluetooth Low Energy Technology and Classic Bluetooth Technology?

With the introduction of Bluetooth low energy technology, considerable interest has been seen on its possibilities. Bluetooth low energy technology has some important limitations as well as benefits; it is quite different from Classic Bluetooth technology:

  • Bluetooth low energy technology enables new applications and is ideal for applications requiring episodic or periodic transfer of small amounts of data.
  • In a Bluetooth application where streaming data is used, Classic Bluetooth technology is the preferred choice as it achieves substantially greater throughput than Bluetooth low energy technology.

If you want to get a quick introduction to the differences between the technologies, have a look at this introduction video.

Power consumption:
Since a Bluetooth low energy device is in sleep mode most of the time - the maximum/peak power consumption is only 15 mA and the average power consumption is of only about 1 uA.

Connection set-up times:
In Bluetooth low energy technology the actual connection times are of only a few mS and thereby the connection is quickly initiated as the device wakes up.

Robustness:
Many features of Classic Bluetooth technology are inherited in Bluetooth low energy technology including Adaptive Frequency Hopping (AFH) as well as part of the Logical Link Control and Adaptation Protocol (L2CAP) interface.

Throughput:
Data transfer rates with Classic Bluetooth technology using Enhanced Data Rate (Bluetooth v2.1 + EDR) can exceed 2 Mbps (actual payload), but practical transfer rates for Bluetooth low energy technology are below 100 kbps (actual payload of roughly 1/20).

Profile support:
Bluetooth low energy technology provides no support for the Serial Port Profile (SPP) in the standard Specification v4.0; although suppliers like connectBlue can provide a good level of support. Many other profiles are not offered for Bluetooth low energy technology because of the differences in the connection models. The Classic Bluetooth scenarios that are not part of Bluetooth low energy technology include headset (HSP), object exchange (OBEX), audio distribution (A2DP), video distribution (VDP) and file transfer (FTP).

Number of nodes:
Just as with Classic Bluetooth technology, Bluetooth low energy technology is based on a master connected to a number of slaves. However, in Bluetooth low energy technology the number of slaves can be very large; how large depends on the implementation and available memory.

Advertising:
The new "advertising" functionality of Bluetooth low energy technology makes it possible for a slave to announce that it has something to transmit to other devices that are "scanning." "Advertising" messages can also include an event or a measurement value.

Software structure:
In Bluetooth low energy technology all parameters have a state that is accessed using the Attribute Protocol. Attributes are represented as characteristics that describe signal value, presentation format, client configuration, etc.

Apple connectivity:
Bluetooth low energy technology – which is implemented in iPhone 4S – supports Apple connectivity without the use of an Apple Co-processor.

 

Classic
Bluetooth technology

Bluetooth
low energy technology

Data payload throughput (net)

2 Mbps

~100 kbps

Robustness

Strong

Strong

Range

300m

250m

Local system density

Strong

Strong

Large scale network

Weak

Good

Low latency

Strong

Strong

Connection set-up speed

Weak

Strong

Power consumption

Good

Very strong

Cost

Good

Strong

 

“Single-mode” and “Dual-mode” – What Does That Mean?

Classic Bluetooth implementations are single-mode implementations. But with the addition of Bluetooth low energy there are also single-mode Bluetooth low energy devices. Because the two technologies are fundamentally different, there are the two following options for low energy implementations:

  • Single-mode Devices:
    These devices are stand-alone Bluetooth low energy devices (also known as "Bluetooth Smart” devices) optimized for small battery-operated devices with low cost and low power consumption in focus. A typical single-mode device is for example a heart rate sensor.
  • Dual-mode Devices:
    These devices (also known as “Bluetooth Smart Ready” devices) include both Bluetooth low energy technology and Classic Bluetooth technology. Dual-mode devices will rarely gain in power saving since they need to support both technology implementations; the power savings will only be achieved with the single-mode option. A typical dual-mode device is a mobile phone or PC.

In a dual-mode implementation, you can for instance, in parallel, connect a number of Classic Bluetooth single-mode modules (OBS410/411/etc.) as well a number of Bluetooth low energy single-mode modules (OLS426) to a Bluetooth dual-mode module (OBS421). You can also connect Bluetooth dual-mode modules to one another. Go here, to learn about the connectBlue Bluetooth low energy products.

What is the Difference Between Bluetooth Specification Versions?

Classic Bluetooth v2.1+EDR was adopted by the Bluetooth SIG in 2007 and is fully backward compatible with v1.2. EDR stands for “Enhanced Data Rate” which allows for the maximum application throughput of connectBlue modules of 1.4 Mbps.

Products that comply with Bluetooth v3.0 are built on the v4.0 specification (see below) but do not include Bluetooth low energy. Bluetooth v3.0 is Classic Bluetooth and since it consists of legacy Bluetooth protocols, it offers backwards compatibility. Bluetooth v3.0+EDR offers Enhanced Data Rate.

Bluetooth v4.0 was adopted by the SIG in 2010 where Bluetooth low energy offers an entirely new protocol stack for rapid build-up of simple links. Bluetooth low energy has inherited features such as Adaptive Frequency Hopping (AFP) from Classic Bluetooth, but from an application perspective it is different. All devices that comply with v4.0 includes Bluetooth low energy which offers a throughput of a few kbps.

What is the Difference Between Bluetooth Smart and Bluetooth Smart Ready?

To simplify the understanding of Bluetooth capabilities, the Bluetooth SIG introduced the Bluetooth Smart marks in 2011. Simply put, a Classic Bluetooth device would use the original Bluetooth mark while a single-mode device would bear a Bluetooth Smart mark and a dual-mode device would bear the Bluetooth Smart Ready mark. While the use of these marks and terminologies are recommended by the Bluetooth SIG, they are not mandatory.

Wireless Selection Guide

Wireless Selection Guide

If you want to learn more on various wireless use cases, wireless technology comparison, what makes connectBlue unique and the technical differences between the connectBlue wireless products and modules, have a look in our Wireless Selection Guide.

The connectBlue Wireless Product Range

The connectBlue wireless product range cover Classic Bluetooth products, Bluetooth low energy products, Wireless LAN /WLAN (IEEE 802.11a, b, g, n) products and IEEE 802.15.4 / ZigBee products. If you want to compare products regardless of wireless technology, select from the following options:

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Wireless Modules

       

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