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Hands-free car phone safety with Bluetooth

Fitting a traditional in-car hands-free kit often involves matching the interface to a specific handset, resulting in the need to reconfigure the entire kit, should the user change handset. Hopefully, Cambridge Silicon Radio has found a simple, usable fix ... which could appear on cars from Audi very shortly.

Faced with imminent car safety legislation, the car industry has dithered. But at last, a proper working example of how to integrate a Bluetooth-enabled phone with a car's hands-free requirements has been put together; it could lead to sensible, usable systems appearing on the market in cars soon.

An in-car Bluetooth connection eliminates the need for a phone cradle completely, and as the CSR BlueCore2-External chip set is a Class 2 device with a range of at least 10m, a user's handset could still be in use whilst in a briefcase or bag - or even in the boot.

But earlier solutions were very difficult to set up, and prevented the user from switching seamlessly from bluetooth headset to car hands-free.

The new design hasn't been tested yet by NewsWireless, but since the author of the design is Cambridge Silicon Radio, there are good grounds for optimism that it will work properly.

The example design is AutoSira, which, it hopes, car makers will be able to take on board quickly - which would be something of a change for the auto business, where designs evolve slowly.

AutoSira includes all the Bluetooth software, data and schematics required whilst leaving space for the individual designer to incorporate their own specific features and functionality. The example design is available now on CSR's website and they claim it includes details like a bill of materials and application notes - but a brief scan of the site wasn't enough to find this - you'll need to search.

The full release is at http://www.csr.com/pr/pr122.htm.

and shows how CSR's BlueCore2-External allows designs that can be tailored to suit both after-market type solutions and embedded OEM type solutions.

BlueCore2-External contains a 16-bit RISC microcontroller, on which CSR has implemented a Virtual Machine (VM). The VM makes it possible to create a bespoke application without the designer having to reconfigure the existing Bluetooth stack. As the VM is layered on pre-qualified RFCOMM firmware the time and cost of qualifying a new Bluetooth product is greatly reduced. Schematics for the AutoSira design include both PIO (Parallel Input Output) and UART control.

The company claims that its BlueCore is the only Bluetooth silicon on the market guaranteed to operate across the full temperature range for in-cabin electronics systems of -40degC to +105degC. In fact, they say, it can exceed those specs.

CSR also claims that BlueCore is the only automotive grade Bluetooth solution available which can run the complete Bluetooth protocol stack and application software on-chip, without the need for an optional external microprocessor.

Anthony Murray, Bluetooth Automotive Specialist, CSR commented, "As legislation veers towards increased restriction on the use of mobile phones in cars, Bluetooth is expected to play a pivotal role in enabling the safer use of handsets in cars."

Murray continued, "Audi has already identified the benefits of Bluetooth and has taken the step of integrating CSR's BlueCore technology into its vehicles. With this ready-engineered handsfree design example, CSR is able to lead automotive manufacturers to take a technological leap."

There are industry experts who estimate that up to 70 percent of all mobile phone calls are made from cars. Bluetooth hands-free systems provide a safe, convenient alternative and are already proving to be a successful application for automotive Bluetooth.

Future applications are likely to include vehicle diagnostics and personalisation features where the car can identify its user by the handset that they carry, so for example, the vehicle's temperature and seat position could be adjusted accordingly.