Development Of Drivers For A Portable Water Analyzer

With the gradually severe problems about water-contamination, the group of the project determines to develop a mobile and on-line water-environment monitoring platform, which consists of an embedded on-line data collection sub-system and a centralized data analyzing and exhibiting sub-system. As the data entrance of the whole platform, the portable on-line water quality monitoring device should have some functions including the measurement of several chemical components in water sample, a friendly user-machine interface, access of 3G Internet and voice-call, service of GPS precise location, etc. The main content of this article is just the development of drivers of this portable on-line measurement device.To develop the appropriate drivers, the first step is to build a development environment, including installation and setting of the server, setting and compilation of source code in each part, fabrication of Image file, etc. Then the second step is design of hardware scheme, i.e., the design of model circuit based on the interface in the core board, including high-efficiency DC buck circuit, signal level conversion circuit, peripheral circuit of module and chip, etc.The kernel part of this work is the driven development of the four function modules for Android platform, and each module is divided into two parts: the driven development in Linux system; the interface implementation in Android system.In the device, the rapid measurement module of multi-parameters for water communicate with main controller using serial port. The author first brings about serial port driver in Linux, and encapsulate self-defined communications protocol as common class for use of application. In Linux, the touch screen driver mainly involves LCD driver, I2 C driver framework, external input interrupt and input sub-system, etc. Then the author packages bottom operation details of the screen by migrating Gralloc dynamic library according to the interface ascertained by Android. Driver of 3G mainly includes the USB driver framework in Linux and the migration of the Radio Interface Layer(RIL) libraries in Android. The driver of the service of GPS precise location, which also uses serial port, is the UART driver in Linux and the implementation of the Hardware Abstraction Layer(HAL) layer in Android.The last of this work is the testing of driver about the four modules, and each driver runs successfully and achieves the purpose. These drivers will lay a good fundamental for the development of APP and design of whole platform in later stage.