Proximity detection is commonly required in mobile computing environments and sensor networks, and is a key technology to enable certain location-based services and to actuate or trigger reactions in certain automated systems or appliances. Typically, special proximity sensors are used. However, they usually provide only rough proximity information. To obtain higher precision, specially designed hardware or infrastructure support are required.
 
In this project, we design key algorithms that use only very cheap and widely available sensors, namely microphone and speaker that are standard configuration of any mobile phone, to perform high precision proximity detection, without infrastructure support and device synchronization. The key idea is to use the pair-wise differential time of arrival (DTOA) of sound signal between the two devices to infer the distance. This technology is applied to the MobiUS project to ensure the video is dynamically expanded to two screens or shrunk into one screen when the two mobile devices are close or faraway, and the relative position of the two devices is also automatically determined. We also build an ad hoc microphone array system using multiple mobile devices where the proximity detection technology plays a key role.

• Chunyi Peng
• Guobin (Jacky) Shen
• Yongguang Zhang
• Visiting students that worked on this project
• Yanlin Li (Tianjin Univ. China)
• Zheng Han (Beihang Univ (BUAA) . China)

1. Chunyi Peng, Guobin Shen, Yongguang Zhang, Yanlin Li and Kun Tan, "BeepBeep: A High Accuracy Acoustic Ranging System using COTS Mobile Devices", ACM SenSys, 2007. [pdf]

Currently,BeepBeep supports Pocket PC phone edition running Windows Mobile 5.0 or higher.

Device	OS	Package	Release Date
Pocket PC	WM 5.0 or higher	BeepBeep-Setup-V1.0.3	Nov 8, 2007

Pleases run the installation package (.msi) directly at your host PC and also find a .CAB file in the installation package. You can install this BeepBeep package by ActiveSync from your host PC or directly execute this .CAB file in your mobile phone. Finally, the BeepBeep should be installed at \Program Files\BeepBeep\, and you can find the below files in it:

• BeepBeep.exe
• Config.txt
• Config-advance.txt
• BeepBeep-Readme.txt (the help file)
• ReleaseNote.txt
• ProxmityDetection.dll (algorithm implementation)
• Wavfile (folder of wave files)

All defaul setting of BeepBeep system can be found in config.txt. By default, BeepBeep runs on WiFi ad hoc mode under temperature of 25 Celsius. Certainly, you can configure your BeepBeep system if needed. BeepBeep-Readme.txt or this manual has provided most information to run BeepBeep. If you still have problems, you can refer to BeepBeep-FAQ, or contact us for more assistance.

Welcome to download and use BeepBeep. Your feedback are very important and will be highly appreciated.  If you meet with any problems or need additional information, please contact us.

Last update: Nov 21, 2007

Wireless and Networking Group | Microsoft Research Asia