SpyPhone / BabyPhone is a Python-application that monitors the surrounding sound level.

At the core of every mobile phone, there’s still the voice channel. Therefore, every phone is equipped with a microphone that’s optimized at recording the human voice. Add the aspect that the phone is mobile and that the owner usually carries it with him all the time, it’s no surprising thought that the phone can be used as a remote surveillance tool.

BiBUnit is based on a rather simple concept and essentially accepts incoming video calls if a previously set number is calling, allowing you to monitor the surroundings through the phone camera. SpyManager on the other hand lets you take remote snapshots of through phone, also through a PC server application.

Similar, but with a different usage scenario is Phone Guardian, which allows remotely controlling aspects of the device in case it was stolen from you. SecureMe is built based on the same concept.

SkyeSpy turns the situation around and alerts the observer autonomously. The application on the "spy"-phone is able to monitor the audio level of the surroundings. If it exceeds a threshold, the phone will contact a previously paired phone per SMS or a call.

There might be other applications around that I missed, but the list should give you an overview of what is currently possible on a S60 phone.

SpyPhone / BabyPhone

Now the students Clemens Rainer and Daniel Haslinger went up to the task of implementing this application via PyS60 and have released their results for free as an open source application called SpyPhone or BabyPhone.

Like the SkyeSpy-application, the phone constantly monitors the audio level of the surroundings. If a pre-defined threshold is exceeded, the phone automatically calls the number of a pre-defined "agent".

A good use-case would be the monitoring of a baby. When it starts to cry, the phone will automatically call the number of the parents. As the call is a normal voice connection, they can hear what’s actually happening. If it sounds serious, it’s about time they pay a visit to the child.

Technically, the application is constantly working on two tasks. The first records the sound into a file on the device. In the meantime, the other task analyzes the previous sound file. The next step would be to add more sophisticated sound processing to the application. Instead of just calculating the volume like SkyeSpy does it as well, it would be possible to measure the frequencies in the recorded sounds and only react if these are in the range of the human voice.

As the SpyPhone / BabyPhone application is available as open source, it provides an ideal starting place for your own audio experiments in Python for S60.