Bluetooth today is understood by many as a convenient connectivity solution. Yet there are limitations regarding its flexibility and this entry serves to discuss some misconceptions about Bluetooth Low Energy (BLE or Bluetooth Smart) and classic Bluetooth.
We often receive projects that involve Bluetooth communication, yet many of our clients specify “BLE” without understanding the technology sufficiently. Many assume that BLE is simply classic Bluetooth or Bluetooth v2.x, but with much lower energy consumption. I don’t blame them for the misconception, since our latest mobile devices, e.g. mobile phones and tablets have been touting BLE as if it is a replacement for classic Bluetooth. Furthermore, the name – Bluetooth Low Energy – isn’t much of a help in undoing the misconception. Hence, I have decided to contribute this article and, hopefully, it can be of help to some of you who are reading this.
Before I begin, I would like to say that this is not an extensive article. It will be about the top most common misconceptions that I have often encountered. For the benefit of those who aren’t familiar with BLE, do read these pages for a good introduction (here and here).
Misconceptions
1. Using BLE to perform high-rate data streaming
At this junction, if you have read enough about BLE, you should have an inkling that it was chiefly designed for low-rate of data applications, e.g. Internet of Things (IoT) sensor nodes and Human Interface Devices (HID). Unlike classic Bluetooth, BLE has very low data throughput. This is because of the optimizations made to the Bluetooth profiles and Logical Link Control and Adaptation (L2CAP) to achieve low energy consumption.
To give a sense on how low is low data throughput, I will put forth a scenario. However, before that you have to understand that data in Bluetooth is split into packets and exchanged through one of 79 designated Bluetooth channels. The scenario that I will be putting forth will be based on a Generic Attribute Profile (GATT) structure that most BLE devices utilize with the following settings:
• ARM M0+ chip (operating frequency of 48MHz)
• Connection Interval of 7.5ms, which is the lowest setting (I will explain more later but typically, shorter connection interval results in higher throughput)
Connection interval (CI) in BLE is defined as the time period before the radio jumps to another channel. A shorter CI will result in a lesser amount of packets being sent before the radio switches channel. Since swapping channels will result in downtime, you may begin to think that the CI should be as long as possible so more packets can be sent through one channel. The idea of having a longer CI to reduce downtime and hoping it will result in higher data transmission rate does sound feasible. However, life is often not that straight–forward, especially when it comes to Radio Frequencies (RF). A longer CI will also create more opportunities for RF interference to set in, and corrupt your transmission and connection event. Thus, it leads to an even lower data transmission rate.
Under the aforementioned settings, I typically get around 1 packet per connection event (7.5ms). In 1 second, I will get 133 packets transmitted and with an MTU of 23 bytes, my data throughput is 3059 bytes per second. However, take note that the L2CAP profile on BLE devices takes 3 bytes for the notification process. As a result, only the remaining 20 bytes will contain the actual data that you desire, if you spec-ed it for the notification process.
I hope that it is clear to you now that BLE is not cut out for high-rate data streaming. If you wish to perform high-rate data streaming like file transfers, please stick to classic Bluetooth.
2. BLE doesn’t auto-connect like classic Bluetooth
Very often I am asked, “Why doesn’t the BLE device auto-connect when I turn it on, even after pairing?” The answer is very simple. BLE devices don’t auto-connect like a classic Bluetooth device because it wasn’t designed to do so.
Natively, only classic Bluetooth like Bluetooth v2.x + EDR has native reconnect functions. However, all is not lost; you can simulate the reconnect feature by writing the feature into your software. The only problem is that your software must be running in the background for that to work. Therefore, if you are working on a device that requires constant connection, make sure you write a “ping-pong” feature to support “auto-connect”.
Thank you for reading this article. Hope you find it useful and do remember to share our article. Feel free to comment below.
We love taking photos. Wefies. Selfies. You name it. But if you’ve tried to use a smartphone camera in less than optimal lighting conditions, you’ll find your pictures poor and unworthy of that coveted Facebook post. A problem we often face when taking a selfie is that besides having a poor front-facing camera on a typical smartphone, there isn’t a front-facing LED flash! That means unflattering and poorly-lit selfies.
The reason is that complementary metal-oxide semiconductor (CMOS) photo-sensors used to fit in the smaller confines of a smartphone generally have poor performance in low-light conditions. The difference is noticeable if you compare the quality of photos taken with a DSLR versus a smartphone. The smaller sensors deployed in a smartphone have less area to collect light. A larger DSLR will accommodate a larger sensor, and, in turn, a larger sensor will collect more light to produce a better image. This is why the number of pixels doesn’t matter. A camera with a large or more-sensitive sensor will produce superior results over any smartphone with a small sensor, even if both tout the same number of megapixels.
With a small sensor, the pixels can’t capture as much light, so a smartphone camera will produce images that have less vibrant colours than a DSLR. A camera with a smaller sensor will also produce images with more noise, especially at high ISO. Of course, the trade-off in image quality means more convenience. We don’t always carry a bulky DSLR wherever we go, but the ubiquitous smartphone is now an extension of our modern lives. How can we get better pictures in poor lighting conditions without modifying our smartphones or lugging a DSLR everywhere?
The solution? Add more light to your scene or subject; behold, Portable light prototyping for smartphone photography.
There are many pocketable lighting options which promise smartphone-friendly illumination. They range from essential LED lights to more sophisticated gizmos which your smartphone can control.
The Pocket Spotlight is the simplest of the lot as a simple array of 32 LEDs. Gizmag gave it a positive review, and it does what it’s advertised for US$30 – plug into your smartphone for extra light.
The Nova and iblazr2, on the other hand, have more features. The Nova Bluetooth iPhone flash is a credit card-shaped Bluetooth-controlled LED flash consisting of 40 warm and cool LEDs. A notable feature is that temperature and brightness can be controlled from the free Nova Camera app, which is especially useful for shooting objects with a warmer or cooler colour tone. It’s compatible with iPhones, from the iPhone 4s onwards. Up to 10 units can be simultaneously triggered for more advanced lighting setups, given its slim, compact and pocket-friendly design with colour temperature adjustments.
The iblazr is also an LED flash and constant light for your smartphone, only this time it’s not iPhone. The small LED unit attaches to the headphone socket of your iOS (7+), Android (4.0 or higher) and Windows Phone (8. x) smartphone. Like the Nova, the iblazr connects to your phone via Bluetooth, and the accompanying app can adjust brightness and sync with the camera shutter on the device. It is already in its second iteration, with the original retailing for US$40. The new iblazr two is going for US$59.90 and boasts a variable colour temperature from 3200K (warm) to 5600K (excellent), which can be adjusted in the accompanying Spotlight app or via a touch sensor on the rear of the device. It offers a very similar performance to the Nova.
The light strip casing is a notable mention that attempts to solve the problem by integrating a ring-light-like construction into the phone’s casing. Unfortunately, it means the product obsolesces when the smartphone (iPhone5/5S) is replaced with a newer model. The maker’s Kickstarter campaign was unsuccessful, and lessons can be learned here.
All these external lights have one thing in common; they offer diffused lighting to illuminate a subject and are typically targeted at smartphone photography. Nova and iblazr offer nifty features such as Bluetooth connectivity and light temperature control, giving portrait shots warmer tones.
Colour temperature
For lighting frequently used for portrait shots on faces (for example, selfies and wefies), it is essential to have a feature for selective temperature colour for your light source. Nova and iblazr offer this feature. A helpful article on the effects of light temperatures on face shots is covered in an article here.
What’s still lacking?
With that said, USD$60 for a simple light source can prove a tad pricey for the average user or teenager, especially when he has spent his savings on the latest iPhone 6 Plus.
A flash can be surprisingly harsh (especially on the iPhone) and momentary. The Pocket Spotlight’s constant light acts as a floodlight, allowing a user to illuminate a scene where focus and exposure could be adjusted before the shot. Still, it doesn’t have dual-tone colour temperatures for warmer lighting. The Nova is an excellent bet, but it is currently compatible with iOS7 or later and has only flash functionality, while iblazr has 4 LEDs (just two more than an iPhone 6) which doesn’t add all that much light.
We decided to put together a DIY light prototype with minimal hassle and just spare parts around the lab; a quick DIY lighting source can be put together. Here’s what we did:
For power, a spare USB power bank lying around would do nicely, giving a reliable, regulated 5V power source up to 2A, which allows 10W of power to be drawn since the LEDs we’ve selected are power-hungry.
Rummaging through the storage for LEDs revealed a few versatile, low-cost chip-on-board (COB) LED modules, in which multiple LED elements are directly mounted on a substrate and encased in epoxy. COB case-less LEDs enable a much denser LED array of light compared with traditional surface-mounted device LEDs. More on COB-type LEDs here. The LED module selected is a 6-7V, 3-Watt COB LED Strip outputting 250 lumens of 3500K warm light and another strip providing 300 lumens of 6000K cool white light. Since the LEDs are rated at 6-7V, higher than the 5V of the power bank, we used an LM2577S-based DC-DC step-up voltage regulator to boost the voltage to about 6.5 volts.
I am testing the DC-DC boost converter from a 5V power source.
The metallic casing of the power bank would conveniently act as a heat sink for the LEDs.
Power is drawn directly from the USB port using a slim printed circuit board (PCB).
Soldering all the wires together with two switches, one for ON/OFF, the other a selector between the two LED colour temperatures. Everything is held down by glue.
The LEDs are mounted with some thermal paste onto the power bank and epoxied down.
And she lives! It wasn’t much work, and the whole ghetto setup works just fine.
It gets a little warm to touch after a while, so we wrapped it up in faux leather.
A couple of hours later, all ghetto, DIY and dandy!
Works great!
A couple of test shots of random stuff lying around the lab.
Let’s see how our DIY light source fares against LED flashes of smartphones. An Apple iPhone 5S outputs a mere 60 Klux, the iPhone6 Plus at 67 Klux and an HTC One about 107 Klux.
Our DIY light blows the darkness away! One single cool-white COB-LED gives us approximately 360 Klux of light, while two warm-white COB LEDs output ~240 Klux of light. That’s three to four times brighter!
Our DIY, rapidly-made, simple dual-colour temperature (3000K, warm) and (6500K, excellent) light source for off-camera photography! It doubles nicely as a portable lamp, too, to charge. Simply plug in any micro-USB cable 5V USB power source. Add light to your photos anytime, anywhere. All in all, the development cost of this project is about US$15 for a power bank, US$3 for a DC-DC regulator module, US$2/COB LED, $0.10 switches wires and miscellaneous, which works out to be about 20 dollars project.
Not as low-cost as we would have liked, but it was fun, and actual BOM could be further decreased without all that bulk from the parts we used. A $10-$15 price for such a gadget could be very feasible.
Nevertheless, we’re now the proud owners of a nifty dual-tone light source for all the selfies and wefies we will take.
Drop us a comment if you like this post, and if you’re interested in obtaining a portable light source of your own, we would be happy to run a small production run of such light gadgets with enough interest.
You’re likely to own a Bluetooth-enabled device by now – your phone is one. Bluetooth-enabled connectivity exists in a variety of consumer electronics and has become a socially understood means of convenient wireless communications.
Bluetooth capability can be found in almost every decent smartphone, tablet, wireless mp3 speaker and in-vehicle entertainment system to even household appliances like a rice cooker or refrigerator.
However, did you know that there are many versions of Bluetooth? Since its inception, Bluetooth has been a wireless technology standard for exchanging data over short distances via small Personal Area Networks (PANs) and it has evolved over the years with newer functionality and capabilities that consumers know little about.
Bluetooth has now evolved to Bluetooth 4.0 standards and beyond – also known as Bluetooth Low Energy (BLE4.0), Bluetooth® Smart or simply “BLE” or BLE4.0.
Bluetooth Smart Technology: Powering the Internet of Things
As consumers demand longer battery life from their mobile devices and the power efficiency of communication modules has come under scrutiny, a device with Bluetooth connected all day will undoubtedly lead to a decrease in battery life. Bluetooth® Smart is the intelligent, power-friendly version of Bluetooth wireless technology.
Bluetooth® Smart is a new generation of Bluetooth connectivity with enhanced power efficiencies targeted at mobile battery-powered applications, yet retaining its ability to be backwards-compatible with all other versions of legacy Bluetooth. You can pair existing Bluetooth headsets with a new smartphone or tablet you already own or new Bluetooth headsets with older mobile devices.
Now, because of BLE, consumers are seeing everyday objects featuring Bluetooth connectivity. Developers are attempting to make devices “smart” by incorporating Bluetooth, and today we start to see smart locks such as SKYLOCK and Noke lock marketed with BLE-enabled features.
New applications have also been made possible with BLE. Ever forgotten where you placed your keys at home? Tile is one such product targeted at short-distance location-tracking. Consumer reaction has been somewhat lukewarm, but that hasn’t stopped similar products from popping up, such as Lupo, Pebblebee, Hipkey and XYfindit just to name a few.
With BLE’s ability to connect to smartphone apps seamlessly; developers and sports and fitness companies are empowered to integrate this new technology. The market is now seeing a wide range of devices such as Bluetooth-connected heart-rate monitors, clothing and even running footwear.
What does this mean?
The world is exploding with an incredible array of devices connected via BLE. Everyday appliances and devices can now be seamlessly connected to a control device – the most ubiquitous is your smartphone and this development is accelerating the growth of the Internet of things (IoT).
Research companies Cisco, Texas instruments and ABI Research project that some 30 billion to 50 billion devices will enter into the IoT ecosystem by 2020. What this means is that IoT will have a tremendous impact on businesses, consumers and everyday life.
These newly connected devices will produce new types of data that will, in turn, produce new information and knowledge that enable a gain in business efficiencies and enhance customer and consumer satisfaction. IoT will also have a profound impact on people’s lives. It will improve public safety, transport, and healthcare with better information and faster access to this information.
Imagine waking up for a run listening to music with headphones that monitor your heart rate and pace. Your smart-toothbrush will have sensors and algorithms that monitor the state of your dental health. These Bluetooth-connected devices are targeted at reducing wire clutter while allowing you to benefit from the convenience, empowerment, and freedom of BLE technology.
Developing with Bluetooth Smart
As a developer, Bluetooth® Smart is a powerful technology enabler limited only by your imagination and creativity. What are the advantages of BLE over legacy Bluetooth 2.0?
Reduced power consumption – BLE4.0’s Ultra-low peak, average and idle mode power consumption consumes half as much energy when active and transmitting, and 1/100th the energy when in sleep mode. This means longer battery life for mobile devices with an ability to operate for months or years on standard coin-cell batteries. In many cases, it makes it possible to operate these devices for more than a year without recharging.
Enhanced range – The majority of Bluetooth devices on the market today include the basic – 10m range of the Classic Bluetooth radio, but there is no limit imposed with BLE. Manufacturers may choose to optimize a range of 50m and beyond, particularly for in-home sensor applications where a longer range is a necessity. Increased modulation index provides a possible range for BLE of over 100m.
Simplified pairing process – Pairing is now quicker (down to 0.1s instead of 2.0s) and can be done from within an iOS app (instead of having to go through Settings). No complicated handshaking. Just press a button within the app – you’re paired!
Background operation – Once paired, the Bluetooth device can wake up the mobile device with a pop-up notification or an interrupt, even when the app is in the background.
Convenient data retrieval – Obtaining data is no longer constrained by the Classic Bluetooth profiles or Apple’s proprietary 32-pin connector and its expensive MFi Program, which in turn results in a shorter, simpler and cheaper development cycle.
Backward compatibility – BLE allows two types of implementation, dual-mode and single-mode and the resulting architecture shares much of Classic Bluetooth technology’s existing radio and functionality resulting in a minimal cost increase compared to Classic Bluetooth technology. Manufacturers can also use current Classic Bluetooth technology (Bluetooth v2.1 + EDR or Bluetooth v3.0 + HS) chips with the new low-energy stack, enhancing the development of Classic Bluetooth-enabled devices with new capabilities.
Frequency hopping – BLE uses the adaptive frequency hopping common to all versions of Bluetooth technology to minimize interference from other technologies in the 2.4 GHz ISM Band. Efficient multi-path benefits increase the link budgets and range.
Host control – BLE also places a significant amount of intelligence in the controller, which allows the host to sleep for longer periods of time and be woken up by the controller only when the host needs to perform some action. This allows for the greatest current savings since the host is assumed to consume more power than the controller.
Low latency – BLE can support connection setup and data transfer as low as 3 milliseconds, allowing an application to form a connection and then transfer authenticated data in a few milliseconds for a short communication burst before quickly tearing down the connection.
Robustness – BLE uses a strong 24-bit CRC on all packets ensuring the maximum robustness against interference.
Strong security – Full AES-128 encryption using CCM to provide strong encryption and authentication of data packets.
Common terms discussed amongst developers dabbling in BLE:
Universally unique identifier (UUID) – UUID is typically a 128-bit identifier standard used in software construction, however, Bluetooth Special Interest Group (SIG) has a set of defined services and descriptors in a 16-bit address specific to Bluetooth. Any value with a UUID can be listed as an attribute which refers to specific Bluetooth services and characteristics.
Generic Access Profile (GAP) – Controls connections and advertising in Bluetooth. GAP is what makes a device visible to the outside world, and determines how two devices interact with each other. GAP typically defines various roles for devices and identifies which device is ‘central’ and which is peripheral. Peripheral devices are small, low-power, resource-constrained devices that can connect to a much more powerful central device. Examples of peripheral devices are devices like a smartwatch, heart-rate monitor or smart proximity tracking tag. A central device will refer to a smartphone or tablet with more processing power and memory size. More information here.
Generic Attribute Profile (GATT) – A GATT is a collection of services of the characteristics and relationships to other services that encapsulate the behaviour of part of a device. GATT tables describe how data is exchanged once the device is connected; more information here.
Services – this refers to what kind of information is being transmitted; is its battery life or heart rate?
Characteristic/descriptors – this refers to a specific value type, a string value or an integer, or a character, and characteristically contains read/write/notify properties; more information here.
In other words, a GATT holds several services, where the services, in turn, hold several characteristics or descriptors.
What is the difference between Bluetooth, Bluetooth Smart Ready and Bluetooth Smart?
The terminology might seem confusing; let’s simplify it.
Bluetooth Smart Ready: Connects with both Bluetooth Classic & Bluetooth Smart devices and is sometimes called dual-mode. This represents devices with both BLE4.0 and legacy protocols; most new tablets and smartphones are as such. BLE smart ready has the advantage of utilizing classic Bluetooth profiles which have a higher data bandwidth when compared to BLE4.0.
Bluetooth Classic: Used for streaming audio or video to a device (For example a Bluetooth headset), this typically represents older legacy Bluetooth peripherals that are not compatible with BLE4.0-only devices.
Bluetooth Smart: Used for low-energy devices that communicate to smartphones (for Example Apple iBeacon, proximity marketing, and heart rate monitors), these are the new generation of BLE4.0 devices that do not have legacy protocol support.
BLE all around us
Because of this newfound power efficiency and lower cost, the viability of new use cases and applications for Bluetooth that were previously limited have reopened new possibilities.
The battery drain concerns are now largely gone; no longer will Bluetooth be an undermined connection on a mobile device. It will likely become one of the driving forces that will continue to push smartphone innovation along at its current, breakneck pace. Technology manufacturers have embraced the new technology eagerly with Apple first introducing the iPhone4S in 2013 to feature BLE-ready capabilities, and BLE is now standard on most new smartphone entrants to the market.
Because of the major improvements in power consumption, it’s easy to see BLE making a big impact on the Bluetooth accessory market and one very prominent wave is in the personal fitness and health market.
Tens of dozens of fitness trackers now available on the market are mostly empowered by a BLE chip. Xiaomi’s MiBand low-cost fitness tracker sold a sensational 6 million units worldwide and is powered by the Dialog Semiconductor DA14580. The DA14580 boasts ultra-low power consumption giving the Mi Band a previously unheard-of battery life of up to 30 days!
Not to be outdone, electronic giant Texas Instruments has a broad portfolio of BLE chip solutions for various applications such as the Microcontroller-BLE CC2541 found in the Misfit Shine, and a newer generation stand-alone Bluetooth controller, the CC2564 is found in Fitbit Surge fitness watch and Pebble Time smartwatches.
Add BLE to your projects today!
In the next few years, the fight for dominance within embedded BLE will continue apace and is, understandably, a concern for developers and manufacturers. As silicon vendors continue to compete for market share, this then brings into question what level of Bluetooth support customers and engineers can expect. 2015 seems to be just the beginning of a battle for market share among vendors like Silicon Laboratories, which recently purchased BLE module manufacturer, Bluegiga Technologies Inc. Not to be outdone, mobile chip-maker Qualcomm giant has acquired UK-based Bluetooth audio solutions provider Cambridge Silicon Radio (CSR), for $2.5 billion!
Today, incorporating BLE connectivity into your device or project is a painless process when using ready-made third-party modules allowing a designer to reduce development time and accelerate time-to-market cycles considerably. In selecting a chip for your project, developers are now spoilt for choice; it is comforting to know that there is an extensive portfolio of BLE solution providers on the market. The type of BLE chipset required depends on your intended application. We’ve tested several modules, and have selected a few prominent ones for your consideration.
The major time-saving feature of these BLE modules is that the BLE protocol stack has been designed by the manufacturer and the modules are mostly certified under various regulations in different countries required of Bluetooth devices. Furthermore, to aid development, manufacturers of these modules often provide a list of application program interfaces (API) to get your application up and running quickly.
Texas Instruments
The electronics giant’s pioneering efforts in the adoption of BLE paid off with their CC2540/CC2541 chipset seeing a large adoption in the wearable market, notably with their presence in devices like Fitbit Flex, and Fitbit Surge and the Misfit Shine.
TI’s CC254X series uses a legacy 8051 core if you’re into Embedded C and Embedded Systems Development. With such versatility, third-party companies like Bluegiga have adopted the CC2541 chipset into their BLE113 module, which serves a large community of DIY enthusiasts as well as professionals. Both Texas Instruments and Bluegiga offer development/evaluation kits to aid development. You can purchase Bluegiga’s BLE113 module by itself and fairly inexpensively.
The extensive library of APIs that is provided usually suffices to develop the services you require unless you intend to develop your own proprietary 2.4GHz protocol stack. Bluegiga allows you can create custom BT4.0 profiles using their simple XML language referred to as BGScript.
As previously mentioned, TI now offers a newer CC2564 chipset that is now featured on the Pebble Time watch. The CC2564 is a Bluetooth and Dual-Mode Controller that supports legacy A2DP for audio transmissions (this is what enables your wireless Bluetooth speaker to receive music from your smartphone), as well as Serial Port Profile (SPP) for high throughput serial data communication (notably for the voice recording feature on the Pebble Time sports).
Texas Instruments SensorTag is a reference design kit that quickly enables beginners to overcome their BLE learning curve with a host of development resources available. The SensorTag boasts a plethora of sensors (temperature, humidity, pressure sensors, an accelerometer, gyroscope and a magnetometer), and the data is easily retrievable with its accompanying app.
It also passes federal certification FCC (US) / ETSI (Europe) / IC (Canada) for Radio Frequencies (RF). There is a section detailing the certifications the SensorTag has received and the steps that you can take to certify your own product.
Nordic Semiconductor
Nordic specializes in ultra-low-power performance wireless Systems on Chip (SoC) and connectivity devices for the 2.4GHz ISM band, with power consumption and cost being the main focus areas. With these core focus areas, it’s no wonder Nordic’s BLE solutions have one of the best value-for-money and power efficiencies in their class.
Nordic’s nRF8001 solution is present in Fitbit Flex activity trackers, and key features of the µBlue nRF8001 include:
· Highly integrated single-mode slave solution; · 32-pin 5x5mm QFN package; · Fully embedded radio, link controller, and host subsystem; · Profiles and application examples included within the µBlue SDK™; · Sub 15mA peak current consumption; · Microampere range average current consumption; years of battery operating life for coin cell battery-powered applications (depending on duty cycle).
Fitbit chose to adopt an SoC design. This approach effectively reduces the physical footprint required to allow a smaller device size, which is justified by a sufficient sales volume of more than 900,000 units in just the latter half of 2013.
However, this approach will be more expensive for small-volume developers and Nordic has licensed its technology to dozens of third-party vendors with a large selection of BLE modules utilizing Nordic chipsets that you can consider for your product. The external links provide valuable information on specific features, Minimum Order Quantity (MoQ), sales channels and pricing of respective third-party vendors.
Nordic has also unveiled party Japanese ODM vendors producing BLE modules based on its newer more power-efficient nRF51822 chipset. One module that we’ve used is Fujitsu’s latest MBH7BLZ07 module which is a drop-in solution with an embedded antenna and a footprint size of only 11.5×7.9×1.7mm.
Cambridge Silicon Radio (CSR)
CSR has been a world leader in Classic Bluetooth for audio transmission. Your Bluetooth headset is likely powered by a low-cost CSR bluecore chipset.
CSR developed its proprietary aptX advanced audio codec BLE profile that is superior and yet compatible with legacy A2DP for profiles for audio transmission. CSR’s AptX compression algorithm boasts low latency transfer rates suitable for audio applications with the added advantages of superior battery life. However, you will need to license these technologies and they often come with a hefty initial investment if developers choose to adopt the SoC approach.
For other BLE data transfer applications, CSR now offers a broad range of BLE kits, notably the CSR8510 which is a dual-mode BLE that supports both the Classic Bluetooth and new BLE profiles. Some designers prefer to have a Bluetooth® Smart Ready dual mode built into their product for backward compatibility.
With its acquisition by Qualcomm, stand-alone product offerings by CSR might become more B2B focused; however, third-party manufacturers such as Bluegiga’s BT111 module still feature the CSR8510 chipset and in another development in the intense battle for market share dominance, Bluegiga has now been acquired by Silicon Laboratories.
Dialog Semiconductor
Dialog Semiconductor is a UK-based company with customers that include Bosch, Sharp, and Samsung, is a smaller less-known underdog in the market of BLE solution providers.
The company recently gained prominence with the successful adoption by Chinese consumer manufacturing giant Xiaomi. Dialog’s DA14580 powers Xiaomi’s Mi Band activity tracker and by far leads the industry in terms of the lowest current consumption and also sports a very decent Flash and RAM capacity size.
If you’re looking for a certified module option, Murata’s LBCA2HNZYZ module is based on the DA14580 – a tiny 7.4×7.0x1.0mm (requires external crystal though) in size and a great selection for any low-power applications.
Murata’s LBCA2HNZYZ is a Bluetooth® Smart module that supports Bluetooth v4.1 BLE standards. All protocol stacks required for Bluetooth low-energy communication are built in, including various healthcare profiles.
Cypress is an American semiconductor design company and it has been making waves in the area of semiconductor innovation with several big-name company acquisitions and versatile product offerings. They offer memory chips, peripheral controllers, touch sensors and proprietary microcontroller architectures.
Their PSoC 4 BLE and PRoC BLE product portfolio has a very short learning curve for any designers new to BLE and offers a plethora of built-in analogue and digital functionality and features capitalizing on their PSoC’s built-in components (Capacitive sensing, ADC, DAC, Op-amps, RTC, I2C, SPI, UART, USB, etc).
Cypress’s PRoC BLE Module is a tiny 10x10x1.8mm module that has already been certified in the US, Canada, Europe, Japan and South Korea, which is great news for developers and expediting a faster time to market.
These truly “plug-and-play” systems come with high reliability and customizability, and you can easily expand beyond these countries to the other markets which recognize some of these certifications.
Certifications
Consumer safety is of paramount importance and should always be an active consideration for any developer. Devices with communications capabilities could pose potential RF interferences or electromagnetic incompatibilities. Certifications ensure that the product is safe and that the RF energy emitted is harmless to the human body. As such, communications devices are regulated by the Federal Communications Commission (FCC) for consumer consumption within the United States and by European Commission (CE) for usage within the European region.
To get a Bluetooth or other wireless product on the market, there is a range of qualifications and approvals you will need to meet to prove that the products meet wireless standards. This qualification involves both testing and paperwork, which can be a relatively complex and costly process for those unfamiliar with the process. Approvals under wireless and teleregulatory standards cannot be obtained on chips alone; they can only be acquired for complete products or sub-systems/modules.
Today, many of the world’s best-known module manufacturers offer modules. These modules are available with the necessary external circuitry and are either partially or fully qualified (with/without integrated antenna) towards relevant wireless standards.
If it is expected that your product will gain significant market share, it is worthwhile for the company to focus on increasing profit margins and move away from procuring BLE modules to adopt an SoC solution instead and acquire its own certifications.
However, the process of doing so requires dedicated R&D effort, Bluetooth SIG membership registration, a declaration to list its products, and certification of the product with regulatory bodies like FCC and/or CE clearance. Let’s explore the options:
CE marking is mandatory for certain product groups within the European Economic Area (EEA), Switzerland and Turkey. The manufacturer of products made within the EEA and the importer of goods made in other countries must ensure that CE-marked goods conform to standards. CE in that sense is similar to the FCC’s Declaration of Conformity which is used on certain electronic devices sold in the United States. Most countries recognize these qualifications and thus permit sales of the product in their respective domestic markets (such as Singapore).
Manufacturers and companies typically strive to achieve such FCC or CE (and a less common UL or CSA) certifications on their products prior to global distribution to expedite entry into the target market by conformance to the country’s economic regulations.
More information on certification processes can be found from certifying agencies such as TÜV Rheinland, and from certifying agencies in Singapore including TÜV SÜD PSB, BSI, and SGS.
Summary
As a developer, there’s no shortage of resources and tools to aid you with your BLE development for your next project. Depending on your level of expertise, there are many development kits and modules from various manufacturers to choose from, and should you choose to use a module, beyond the skills already mentioned, you’ll likely need surface mount soldering tools and abilities to build a prototype board. Not sure how to go about it? Give us a buzz and let our experienced team assist you!
When you intend to incorporate BLE into your existing or future designs, decide whether to use an SoC approach or purchase an existing module after weighing the pros and cons ( mode of application, projected volume, target markets, required certifications, etc). Most designers find it easy to define the “what” about their project, but it is always the “how” which is more difficult.
At the highest level, you can go straight to the chips themselves and design your own custom board. As pointed out above, OEM manufacturers offer a variety of cores and features to fit your full custom product design. With the onset of BLE v4.2, faster and higher transfer throughput with security upgrades and lower current consumption are available for future designs.
Here at Thesis, we’re all fans of the latest and coolest gizmos and [smart]watches. The announcement of the new LG Urbane, the successor to the LG watch R was a surprise owing to the fact that the watch R was relatively new on the market. I got the opportunity to test this smartwatch myself and In my opinion, the watch has been a conversation starter but beyond that, its utility is debatable. Third-party apps can cause the watch to crash, forcing one to restart the device. While it may not be due to the hardware itself, this can really be irritating and there have been instances when I ended up pulling out my phone to check the time. There were also times when I couldn’t trust the time on the watch because it crashed and reset itself. “It’s 10.30am. Wait. 10.35am? No, it’s not… it’s… dang, my watch restarted itself.” Once, the running app crashed and I lost track of my run mid-exercise.
Ever since the explosion of smartwatch entrants in the market in recent years, the technological progress that has gone into wearables has taught us all many lessons, with battery life and health monitoring among the new possibilities this new frontier of technology brings us. Smartwatch reviews online are aplenty, and the LG watch R has gotten coverage on TheVerge and Wired as well as received a good review on Engadget.
Other than the initial kinks, this little buddy has turned out fine so far. Battery life isn’t too bad; the watch can last for just about two days with moderate usage before charging is required. Till the next smartwatch wins its place on my wrist, I must say the LG watch R is a well-made and engineered gizmo with a clear and responsive high-resolution screen. To give it credit, we should find out what makes it tick. A quick search showed that a teardown was done on the LG watch R’s predecessor by iFixit, but not on the R itself.
Today we will see what makes this little guy tick…
The four Torx T5 screws were easily removed, revealing a very simple plastic back plate and a single-PCB.
The first thing I noticed was how neatly organized the board is and how much empty space there is on the PCB. At first glance, you can see the various flex-PCB connectors neatly placed at the corners and edges of the main PCB. That is a good practice; one reduces cost on unnecessarily long flex-PCBs that would cover up precious real-estate on the PCB.
Let’s take a closer look at the populated components.
The most prominent component in the center of the PCB is an optical photoplethysmograph (PPG) heart-rate sensor, which is fast gaining popularity in smartwatches for bio-measurements. For the LG watch R, the heart rate sensor is a TaiwanesePixArt PAH8001 featuring an integrated pixel Array plus green LED sensor in a 3 x 5mm SMD package with a low power consumption of 1.5mA.
If you are looking to build your own smartwatch with photoplethysmograph (PPG) heart rate sensors, there are a variety of alternatives to choose from. Maxim’s MAX30100, JRC’sNJL5501R or NJL5310R COBP photo-sensor and OSRAM’s SFH 7050.
On the bottom right of the main picture, we can see Alps electric Digital Pressure Sensor HSPPAD Series, model D38 JCH8. The low current consumption (9.5μA) makes it suitable for a wearable application like this. Plus, the measurement range is rather wide, at 300 to 1100hPa or 4.35 to 15.95 psi.
These units are quickly calculable – on earth; standard atmospheric pressure is 101.325kPa = 1ATM (1 atmospheres), so 300hPa = 30000Pa = 30kPa = 0.296 ATM, and 1100hPa = 110kPa = 1.086 ATM. This sensor has a range of 0.3 to 1.086 atmospheres.
Right beside the Alps altimeter is the InvenSense MPU-6515 6-axis accelerometer + gyroscope. It features MotionTracking™ SoC Optimized for Google’s Android KitKat 4.4 and has an onboard Digital Motion Processor™ (DMP) which offloads motion algorithms without requiring computation from the main MCU. It features a small footprint of 3x3x0.9mm. Designed for low-power operation, Vcc is at 1.8 volts and consumes only 6.1mW of power in full operating mode, or about 3.4mA.
At the bottom edge, we have the AKM semiconductor AKM8963 H417D compass, a 3-axis electronic compass with a high sensitive Hall sensor with a measurement range of ± 4900 μT. the 16-bit resolution gives it a sensitivity of 0.15 μT/LSB and average current at 8Hz repetition rate: 280μA typical. The MPU-6515 and the AKM8963 combination give it a very nice 9-DOF (Degree of Freedom) with only 3.68mA of power consumption.
Beside the InvenSense gyroscope and above the compass, we have a Synaptics Synaptics ClearPad™ Touch controller, model S3526B 43310013. No datasheet seems to be available but it’s possibly ClearPad Series 3 from the “S3526” markings. The Series 3 allows up to 10 touch points on a screen not exceeding 6” in size. Product brief here, alternative series 3 controllers you could use are S3402B, S3204 or S3250. If you are looking to utilize small touch-screen controllers, other manufacturers include Melfas 8FM006A, Cypress TrueTouch®,Atmel, STMicroelectronics, Microchip mTouch, Silicon labs C8051F76x and Elotouch.
What’s interesting is that while international chip manufacturers such as Atmel, Cypress and Synaptics are now dominating the global touchscreen controller IC market. Melfas, Zinitix and Imagis Technology are emerging as the leading vendors in South Korea. More options are now available to developers!
There’s a missing component here, with the typical array of surrounding Bill-of-Materials (BOM), decoupling capacitors, maybe a few protection diodes. Could be an alternative accelerometer/gyroscope sensor if the latter was not available at the time of manufacture.
It is a good practice for a designer to include sufficient real-estate space for potential logistics issues, one wants to be able to use an alternative component and not let that single component create manufacturing delays for components that have drop-in replacements, and then a simple firmware update and one doesn’t have to go through another round of PCB revisions.
As we move clockwise-left, here we have ON Semiconductor’s USB2.0 DPDT switch. This component is a differential DPDT (Double Pole Double Throw) high-speed USB2.0 480Mbps switch in a tiny UQFN10 casing.
The (AT-K) markings tell us it’s the NLAS7222C 2-to-1 port analog switch. We can see it’s a type “C” because pin 3 on the right is routed to the ground, with pins 4 and 5 going to a tented via (vias covered by solder mask), which on the datasheet is HSD2+ and HSD2-.
Signal data routing inputs from USB go through an EMI/RF filter array at the bottom. Below, on the bottom right could be an EMI filter array to suppress conducted interference that is present on a signal or power line which makes sense coming from the D+/D- of a USB port. Most EMI filters consist of components that suppress differential and common mode interference.
The great thing about such components for designers is that one can now look at price to reduce overall cost, or if manufacturers have drop-in alternative preferences, no downtime is lost on design revisions.
Next, we see an Imagis technology ISOA1423 single supply Haptic driver. Its Imagis ISA1000-series group of haptic drivers work with most ERM (Eccentric Rotating Mass) and LRA (Linear Resonant Actuator) type actuators.
Pins 8 and 5 (top left and right) connect to the E0830 ERM vibrator on the top PCB layer. It’s nice to see such a versatile haptic driver in one IC package.
As for the vibrator… Lots of these are from Chinaland.
Common in today’s multi-stacked modular PCB designs are such board-to-board connectors. The Hirose DF-series is a selection of board-to-FPC connectors, with 0.4mm pitch and a really low profile of 0.98mm mated height. Alternatives include Molex’s SlimStack™ Fine-Pitch SMT Board-to-Board Connectors.
What was especially interesting was the Hirose BM22-4S-V(53) Mezzane connectors, this has a really high power rating, 30V, 4A! It’s designed especially for slim-stacking battery units with a secure fit. Very nice indeed.
We now come to LG’s custom screen, and our unit has the LH130Q01-ED01-QG1 Ver 2.4. The specs tell-all, a 1.3” Full Circle P-OLED with 320 x 320pixels at 246 PPI. No datasheet is available since it’s not for OEM sale, and scrutiny under the microscope shows very intricate construction layers, with the capacitive touch screen layered directly onto the P-OLED screen itself.
Also of note is that LG has chosen to go with the same surface areas for each colour sub-pixel instead of a reduced surface area for green. The top pictures show the powered and unpowered state of the pixel arrangement. A very impressive piece of engineering, vibrant colours on a semi-transparent substrate in a thin package with excellent contrast ratio. Manufacturers of AMOLEDs are now led by LG Display, Samsung, AMOLED corp and Ignis Innovation.
Charging cradle Contacts are your stamped/formed gold-plated metal contacts, no surprises here. A flexible PCB consists of the charging contacts and a membrane tactile vertical push-button with metal shielding.
With that, we can more or less conclude the fairly simple construction approach for the battery cradle and internal support structures.
Part of the PCB that contacts with the metal prong to the casing that acts as the overall antenna.
Now this is interesting, the antenna network goes to a gold pad, which then goes to the gold metal contacts of the plastic assembly, and that contacts the external casing of the watch itself by an un-anodized exposed pad, which means the entire bezel/casing of the watch is the antenna contact to the Broadcom chip.
Now, we take a look at the other side of the populated PCB. The EMI shield came off fairly easily.
Here is the Broadcom BCM4343 WKUBG. Removal of the EM shielding cover from the surrounding mounting clips was a breeze, it wasn’t soldered down and the ground traces were very clear. The three main visible chips under the shield are Qualcomm’s PM8226 Power Management IC, Broadcom BCM4343W communications chip and Hynix-Qualcomm Multi-layered APQ8026 SoC NAND memory (exposed by the shield).
The BCM4343 is an integrated combination chip (Wi-Fi 2.4Ghz 802.11bgn, 4.1/Bluetooth Smart, wireless charging and FM radio and even A4WP wireless charging and FM radio. According to reports, the BCM4343 family has three packages comprising of the BCM4343S, BCM43438 and BCM4343W, each for different applications.
The BCM4343W is designed for wearables with a GCI/UART interface connected to the sensor hub allowing the sensor hub to work directly with the 4343W and bypassing the main MCU – leading to lower power consumption. The Wi-Fi is controlled by an ARM CR4 core, and the Bluetooth by an ARM CM3 core.
A cross-angled perspective of the really low-profile WLCSP; look at the surrounding 0402 passive components. We can appreciate that this is one tiny chip requiring precise reflow soldering. It is an impressive communications chip; unfortunately, LG still denies that the R is capable of utilizing Wi-Fi, likely a firmware or middleware issue they will be able to resolve soon.
The brains of this watch lie in the Hynix H9TU32A4GDMC-LRKGM. It is a multi-chip package, 4GB eMMC NAND (user available memory up to 3 GB), 512MB RAM mobile DDR2.
Taking up the most die real-estate, the Qualcomm® Snapdragon™ 400, 1.2GHz SoC is hidden beneath this DRAM chip. It integrates four Cortex-A7 MPcore Harvard Superscalar cores at up to 1.2 GHz (Quad-Core) and an Adreno 305 graphics card at 450 MHz. Development kits are reported to be available soon.
There are two chips visible here, the “UCAE EFP” is a Fairchild Semiconductor FTL11639UCX. Its a configurable Load Switch and Reset Timer. The FTL11639 is both a timer for resetting a mobile device and an advanced load management device to add a fixed delay of 11.5s prior to disconnecting the PMIC from the battery.
Useful for conditions where one does not want to shut off power to the MCU immediately after the power button is pressed, instead to initiate a shut-down sequence, or vice-versa.
Above the fairchild chip is Texas Instruments BQ27421-G1. It is a Battery Fuel Gauge with integrated sense resistor which provides information such as remaining battery capacity (mAh), state-of-charge (%), and battery voltage (mV).
A must-have for battery-powered devices these days, alternatives include Maxim’s MAX17050, Maxim MAX17043, ONSemi’s LC709203F, Linear’s multi-cell LTC2943 which are available from all major chip manufacturers.
Around it, we have Rohm diodes RB521CS-30 Schottky barrier diode (SOD-882), and NXP PMEG6002EB 0.2 A very low VF 0.2 A very low VF MEGA Schottky barrier rectifiers.
Texas Instruments TPS61282. A decent Power Management Unit (PMU), the Texas Instruments TSP61282 is a battery front-end DC/DC converter, Synchronous Boost-bypass power supply for single-cell portable applications such as this wearable. Its efficiency is up to 95% at 2.3MHz and accepts a wide VIN range from 2.3V to 4.8V and adjustable current limit dynamic voltage scaling.
Qualcomm’s WCD9302 audio codec DAC No detailed datasheet was available for this particular component, but we noted that the Samsung Galaxy S3, Sony Xperia S, HTC One-S and Pantech IM-A850L use the Qualcomm WCD9310 DAC.
An alternative is Cirrus Logic’s WM1811 (formerly Wolfson Microelectronics), a nice 24-bit dual-channel DAC one could use to develop projects with.
Knowles acoustics S1301 2137 microphone
We now come to this component, which is undeniably a microphone, but no datasheet is available based on the the markings. Given the markings and the component design footprint, we think it’s a Knowles acoustics MEMs microphone. The brand has a whole range here. Alternatives include SPM0406HE3H, Cirrus-logic, STMicroelectronics and InvenSense.
Lithium-polymer battery, LG BL-S3 410mAh
This is one well-made battery, and some research revealed that it’s manufactured by Technohill (Yantai)-Ltd, which could be the Chinese contract manufacturer for LG’s battery division. The company specializing in SMT for battery manufacturing and camera modules used in mobile phones is LG Electronics. Headquartered in Bucheon, South Korea, China has established subsidiaries in Yantai.
Its measured volume is 4.16 x 29.3 x 27.7 = 3376.30mm3, the energy density is thus calculated to be 121µAh /mm3.
That is surprising since it’s comparable to the low-cost lipo batteries that we have in the lab. 4.5 x 18.2 x 24.2 = 1981.98mm3 or 121µAh /mm3.
The energy density is the same! Looks like the same typical prismatic packaging and lithium polymer chemistries, nothing new here.
The BL-S3 in the LG watch R compared to a low-cost lithium polymer battery that we use in our lab. No difference in energy densities.
An overview of the component layout on the PCBs.
We’ve come to the end of this tear-down. Although adoption by the masses seems limited, lessons can be learnt from the relatively impressive Bill-of-Materials (BOM) from the tear-down. As the technology improves, it’s likely we will see wireless charging, more WCSP and multi-die chips in the next generation of wearables.
As is the case with the LG Watch Urbane, wearables are gradually improving in both form and function. This watch looks the part, has all the specs you’d hope for in a device of this nature, and wouldn’t look out of place on the wrist of a businessman. But that doesn’t mean it will sell – Android Wear is still too nascent a platform, with too many limitations, to be considered as a viable choice right now.
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