Improving the throughput of smart phone audio-jack based gateway for sensor networks

Sensors and smart phones have been widely used in various applications. Smart phone peripherals like HiJack platform suggest a growing interest in using headset port to access WSN conveniently and efficiently. However, HiJack interface only offers 8,820 baud using a Manchester-encoded communication which is much lower than that of ZigBee. The imbalance of throughput may cause transmission loss and error. We present AudioHTG, turning the smart phone´s headset port into a high throughput gateway of WSN. In contrast with original HiJack work, AudioHTG changes frame format of 12 bits into an “adaptive buffer” which can highly improve valid data ratio. Besides, we adopt enhanced Huffman coding to compress transmission data. Furthermore, we design our own TelosB motes, named GF-100, which are more tiny and integrated for researchers constructing testbed. To validate AudioHTG´s feasibility, we demonstrate a “smart building monitoring” system in our campus.