Sound ID Reduces Size of Headset with xIDE Bluetooth Development Kit

A powerful Bluetooth development tool has helped Sound ID to commercialise an innovative headset for the hard of hearing, which employs wireless communications to link an in-ear module with a remote microphone.

The xIDE software development kit from Cambridge Consultants allowed Sound ID to eliminate the need for a separate microprocessor in its in-ear headset, by fully exploiting the ‘free’ processor that comes as part of the Bluetooth chip, to control the overall hearing system. This resulted in considerable savings, in terms of both real estate and the bill-of-materials. The approach also substantially reduced power consumption – another critical area of performance for this type of product.

Sound ID’s Personal Sound System looks like a small Bluetooth mobile phone headset. However, inside the device is a DSP that can be configured by an audiologist, or the user, to amplify sound based on individual preferences. The Bluetooth capability allows the ear module to link with a remote microphone that can be positioned to improve signal-to-noise ratio. It also acts just like a standard Bluetooth headset for a mobile phone, automatically switching from continuous amplification mode, to hands-free mode when a call is in progress.

The Bluetooth chip used is CSR’s BlueCore device with embedded Flash memory, which includes an onchip XAP RISC processor. This processor’s main task is to manage the Bluetooth protocol communications. But it has enough spare computing power to allow it to function as the application processor in a small ‘hostless’ Bluetooth systems such as a conventional headset, running software such as a hands free ‘profile’ and controlling a simple man-machine interface.

However, Sound ID’s new sound system is much more sophisticated. The versatility of the ear module means that the processor has to run four types of Bluetooth application software: hands free and headset profiles for open connectivity with mobile phones, a custom profile that passes audio between the companion microphone and ear module, and a serial port profile for connecting to a PC for initial configuration. In addition, the processor controls the overall system, including the DSP, and user interface buttons and beeper. This includes managing configuration software that allows the DSP’s amplification and spectral shaping characteristics to be personalized, and different sound settings to be selected during use.

The ability to perform all these functions was made possible by Cambridge Consultants’ xIDE software development kit (SDK). This gives unrestricted access to the full native power of the XAP processor inside BlueCore, allowing users to bypass a software ‘safety’ layer that serves (for less experienced programmers) to protect the Bluetooth compliance of the chip. To help speed the project, Cambridge Consultants also contracted to write the application software for Sound ID, providing a complete system running on XAP that manages both the Bluetooth protocol communications and the sound system requirements, without compromising Bluetooth compliance. Cambridge Consultants also incorporated power conservation techniques to minimize the consumption of the system.

“The xIDE tool allowed us to implement the embedded system in a very economic way,” says Michael Jones of Sound ID. “Without it, we would have needed additional microprocessors in both the ear module and Bluetooth microphone, which would have significantly increased the cost, size and power consumption of the product.”

“The xIDE toolsuite provides Bluetooth developers with the development support they need to squeeze maximum performance out of the BlueCore device,” says Cambridge Consultants’ Tim Whittaker. “Engineers can exploit its facilities to rapidly create advanced single-chip embedded Bluetooth products such as Sound ID’s complex multi-point system.”

Sound ID’s Personal Sound System (PSS) is an innovative wireless personal communications system that can be tailored to a user’s specific hearing requirements and listening preferences. It works in four modes:

  • Amplification mode allows individuals to hear sound based on their hearing preferences. Three user-selectable different SoundFlavors can be programmed.
  • Phone Mode works as a traditional Bluetooth headset for wireless connectivity to a mobile phone for hands free operation. Features include answering and disconnecting from the Ear Module, along with call waiting and call mute.
  • A CompanionLink Microphone can be added to improve communication in noisy environments, such as riding in a car or watching television.
  • One2One Mode supports bi-directional communication between two Ear Modules. This mode is ideal for two individuals who seek improved listening ability in less than optimal situations, such as noisy backgrounds, highly-reverberant environments, and communication from distance.

xIDE for Interface Express provides a complete software development kit (SDK) for developing standalone applications on CSR’s BlueCore(tm) device (with BlueCore running both a full Bluetooth protocol stack and application software – rather than being controlled by a host processor). It offers a powerful integrated development environment that allows editing, compilation, build and debug from within a single tool, making development more productive. Source code and build files are managed using a project filing system that will be familiar to users of similar integrated development environments, helping developers to get up to speed quickly. Developed software runs natively on the XAP microprocessor (which was developed by Cambridge Consultants) integrated within BlueCore, making more computational power available. xIDE for Interface Express includes a large library of qualified Bluetooth Profiles – the software that defines how Bluetooth works in specific applications. More info: datasheet (pdf)

Cambridge Consultants
For over 40 years Cambridge Consultants has enabled its clients to turn business opportunities into commercial successes, whether launching first-to-market products, entering new markets or expanding existing markets through the introduction of new technologies. It develops breakthrough products, creates and licenses intellectual property, and provides business consultancy in technology critical issues for clients worldwide. With a team of over 200 engineers, scientists and consultants, in offices in Cambridge (UK) and Boston (USA), it is able to offer solutions across a diverse range of industries including healthcare, industrial and consumer products, automotive, transport, energy and wireless communications.

Cambridge Consultants Ltd, Science Park, Milton Road, Cambridge, CB4 0DW, UK. Tel: +44 (0)1223 420024; Fax: +44 (0)1223 423373

Cambridge Consultants Inc., 451 D Street, Boston MA 02210, USA. Tel: +1 617 532 4700; Fax: +1 617 737 9889

Sound ID, 3430 West Bayshore Road, Palo Alto, California 94303, USA. t: +1 650 384 3000