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Bluetooth madness

Posted on 16 Jan 2008 at 16:19

Paul Ockenden looks at the options available for making and taking calls when driving, and also examines a wireless security solution.

"Third, power consumption. Complex audio codecs are notorious for gobbling up MIPS and battery power. For example, HEAACv2 (a current favourite MP4 audio codec) requires processor power of typically around 160MIPS to decode, and lots of battery drain - this is simply untenable in a wireless headset.

"Improving the audio quality in Bluetooth applications is becoming a real issue. I previously mentioned the apt-X codec, which has an excellent reputation for audio transparency and is used extensively in radio and by recording studios - if you've listened to the BBC Proms or Classic FM, or have ever experienced surround sound in George Lucas' home audition theatre at The Ranch recording studios in CA, you'll have experienced apt-X. Moreover, the apt-X coding process has a very small latency of around 2ms (during which sound waves travel just 2ft), and it handles marginal RF conditions very cleanly with fast or almost undetectable resyncing for audio recovery. APT has created a wireless version of apt-X, and working with a company called CSR has now ported it to a single-chip Bluetooth component.

"Sorry if this sounds like a commercial plug - it isn't meant to be - but an article on Bluetooth wouldn't be complete if it didn't address audio quality."

I can forgive Quentin the slightly commercial plug because it's a fascinating insight into the problems of using Bluetooth for high-quality audio, which goes some way to explain why the cheaper devices I've been testing over the past few months sound so rubbish.

Wirelessly watching

A few months ago, I mentioned the 3rdi mobile security camera, and how I'd be doing some real-world evaluation to discover whether it's a suitable replacement for the now defunct and sorely missed Nokia PT-6. For those new to the subject, both are smallish devices that you can install in some remote location (holiday cottage, server room, yacht or whatever) to alert you and provide photographic evidence whenever they detect movement. The important difference between these devices and most other security cameras is that they contain SIM cards and communicate directly over the mobile phone networks - there's no need to hook them up via an IP connection or telephone line.

I first wrote about the Nokia device about a year ago in issue 149, which you'll find at www.pcpro.co.uk/links/161mob if you need the full lowdown: a quick summary is that it's essentially a modified camera phone containing special firmware that turns it into a security camera. As soon as it sees something move, it sends you a notification via email, MMS or SMS, and you can even dial the camera's number and listen into what's happening. It's a great piece of kit, but just after I wrote about it Nokia decided to discontinue it. I'm not 100% certain why, but a little Googling uncovered a battle going on between Nokia and someone who claims the PT-6 infringes his patents.

So how does the new 3rdi camera compare to the PT-6, especially when used in the real world? Let's start with the similarities: they're both of similar size and even the same colour (white); they both contain a battery, which means they continue working even if an intruder cuts the mains power; the battery is replaceable in both devices, the Nokia's a standard BL-5C as found in lots of the company's phones, whereas the 3rdi has a custom unit; both use the mobile phone network for communication, having a SIM installed.

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