MSDN Magazine - October 2007 - (Page 91)

Chris Mitchell Mobile Adjust Your Ring Volume for Ambient Noise ou’re sitting in the local coffee shop on a sunny afternoon, peacefully enjoying a quiet moment, when your phone starts to ring. It’s set, of course, to full volume and the ring is so loud you nearly spill your coffee. So you turn it down. Later that day, you’re waiting at a bar for a friend, but he’s nowhere to be seen. He’d forgotten which bar you were meeting at and called to see where you were. Unfortunately, you missed the call because you didn’t hear your phone ring. The problem: the ring volume was still turned down and wasn’t loud enough to hear in the noisy bar. This is fairly ridiculous when you consider that current mobile phones have as much processing power as the first PC I used for multi-channel audio recording. It would seem that with today’s intelligent mobile devices, which are capable of doing so many things and accessing so much information, this problem should not exist. However, everyone who has a mobile phone has experienced this problem in one form or another. The obvious way to solve the problem is to remember to change your volume settings. The option to change the ring volume is presumably to deal with the acoustic differences in various environments, but the functionality does not really do that. Devices should be able to act with a little more common sense. It’s simple: I just want my mobile phone not to ring too loudly in a quiet environment and to ring audibly in a loud place. This article addresses the possibilities and practicality of a Windows Mobile® application that automatically adjusts the Pocket PC’s ring level based on the ambient noise in its current environment. The functionality of this app prevents the phone from ringing too loudly or softly, saving me from embarrassment and missed calls. In this article, I’ll use this problem as an introduction to Windows Mobile development using Visual Studio® 2005 and C#. Apps This article uses the following technologies: .NET Compact Framework This article discusses: Pocket PC development Measuring loudness ✥ Custom installers ✥ Using P/Invoke ✥ ✥ Code download available at: msdn.microsoft.com/msdnmag/code07.aspx Chris Mitchell finished his PhD in machine learning and music/sound signal processing, and is currently a Kauffman/NCGE fellow. He was a part-time lecturer at Anglia Ruskin University, Cambridge, UK, which, along with some network consulting, helped finance his studies. You can contact Chris at c.mitchell at anglia.ac.uk. A passion for music technology led him to explore some of the fundamentals of audio programming, and he is always happy to hear about anything in this area. october2007 91 http://msdn.microsoft.com/msdnmag/code07.aspx http://anglia.ac.uk

Table of Contents Feed for the Digital Edition of MSDN Magazine - October 2007

Cover Contents Toolbox CLR Inside Out Basic Instincts Data Points Cutting Edge Pooled Threads WPF Threads Parallel Linq Parallel Performance Mobile Apps Test Run Foundations Windows with C++ Netting C++ .NET Matters { End Bracket } Net Nuptials

MSDN Magazine - October 2007

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