Thursday, April 29, 2010

The HTG G Sensor

Here is a very simple application that illustrates how to use the HTC G Sensor. This is included in a number of devices (including my own HTC Touch Pro) and it provides a way to determine the spatial position of the phone by providing "tilt" values for the X, Y and Z coordinate axis.

Although HTC did not provide a public API for the G Sensor (shame on them for this), Scott Seligman reverse engineered it which eventually led to a Codeplex project on this subject. The code you see here was ported from the C# version of the Codeplex project back to C++.

The application is quite simple: it merely connects to the G Sensor data source, samples it every 200 ms and displays the tilt values on the screen. As usual, I used WTL to write this simple app and its main features are:
  • The HTCGSensor class that implements an interface to the HTC G Sensor API;
  • The view window (CHtcSensorView) that samples the G Sensor data every 200 milliseconds and displays the tilt values;
  • The frame window (CHtcSensorFrame) where the sampling timer is started (see the OnCreate handler)
The HTCGSensor class has a few points worth noticing: the sensor DLL is dynamically linked through the LoadLibrary API and the data reading function pointer is cached for better performance. Note that access to the sensor data requires acquiring a handle so, proper finalization is required.

Sample code:

The sample application requires an HTC device with a G Sensor like the Diamond. You can use this information in a number of different ways on the device. On a forthcoming post, I will show how you can consume this information on a desktop .NET 3.5 application.

Tuesday, April 27, 2010

Smiling Smith?

Why a new blog? Why this name?

First of all, I want to write about all of my development experiences under one single roof. Until recently I was able to frequently write about native code development on Windows Mobile devices, but due to the recent developments (no native code on WP7), this has become a much harder task. Also, I have recently been working on different technologies (like ASP .NET and XNA) and want to write about them, and the older blogs were too narrow in scope for this.

The blog name is taken from a very old nickname that I never forgot. A few hundred years ago there was a very interesting BBC TV series about an IT consultant named Smith that did a lot of cool stuff. The series was particularly successful on the public television, the only one we had back then. At this time I was working on a very informal team of young developers (remember CP/M?) and there was this older guy who named us all "Smith". Due to my high spirits, I was the smiling one. The Smiling Smith.