SmartSensing: Sensing Through Walls with Your Smartphone!

Seeing through walls and knowing clearly what exist inside just like a superman are not only fantastic wishes for humans, but also of much practical significance. For example, you would like to know whether there are pipes, or rebars inside a wall before drilling into it. Moreover, knowing how pipes are configured in a wall before attempting to fix defects would definitely prevent unnecessary damages. Existing methods that intend to address this issue are either costly due to the use of high-end technology, or too restrictive for reasons of some strong assumptions. However, in this paper, we present a novel system, SmartSensing, which is based on off-the-shelf sensors embedded in smartphones. SmartSensing makes full use of in-built sensors, namely, the accelerometer, the gyroscope, and the magnetometer to achieve this goal inexpensively and conveniently. Specifically, by combining these sensors, we are able to clearly distinguish certain objects inside a wall. In addition, the layout of a pipeline system can be mapped out automatically in an economical and laborsaving way. We implement this system on two different kinds of smartphone platforms, namely iPhone4 and Xiaomi Mi2S. We conduct experiments in a proof-of-concept testbed of size 1.8m×1.0m. Experimental results show that SmartSensing can achieve no less than an average accuracy of 96%, 89% and 77% in distinguishing objects under three different depths, respectively. Also, as for layout mapping, it can achieve less than 32cm and 28cm length error with 90% probability on average for whole horizontal and vertical pipeline segments, with a 6.8m and 4.0m total length, respectively.