Enabling low-cost audio communication for children in developing countries

Research Day Poster April 17, 2007
By: Ashlesha Shintre
Advisor: Dr. Youngmoo Kim


The One Laptop per Child (OLPC) project, also known as the “$100 laptop”, aims to make available groundbreaking computing technology within an extremely limited budget. This effort focuses on the design of a unique laptop computer, called the XO, that will give children in developing countries exposure to an innovative educational computing platform. Widespread adoption of this laptop could revolutionize the pace and proliferation of education throughout all areas of the world.


Our objective is to develop a live voice communication application for the XO that will enable a high degree of interaction between laptop users at a distance. The software-based communication application is designed to to achieve the following goals
i) High quality, low latency duplex audio for effective speech
ii) Efficient data compression with low complexity to meet the constraints
of the hardware and infrastructure.

Core Principles

Ownership is a basic right of every child and entails responsibility to care for and share the equipment.
Children between the ages of 6-12 are the target users. The laptop embodies the principle of constructivism, i.e., learning by playing.
Connectivity between laptops enables growth of the school beyond the walls of the classroom.
Free and Open Source software allows active participation by and contribution from users.
A primary goal of the project is to achieve digital saturation in communities.


Low Power Consumption: Less than 2 Watts of power are nominally consumed and can be generated by the user.
Mesh Network: Every laptop acts as a wireless router. This increases user interaction and strongly encourages collaborative learning.
Easy to use Interface: The human interface, called Sugar, makes use of the laptop a fun experience that promotes sharing and learning.
Fast and Efficient Processor: The XO uses a low-power AMD Geode X-700, CPU speed: 433 MHz.
Open Source Software: The laptop uses the Red Hat Fedora 6 Core version of the Linux Operating System.

Top Left: Network neighborhood Top Right: The TAM TAM activity Bottom Left: Welcome screen


Voice over IP (VoIP) is the transmission of voice data over packet-switched networks (e.g., the Internet) to enable real-time conversations. For instance, Skype is one example of a popular PC-based VoIP application. Our VoIP implementation uses the laptop’s built-in ad-hoc routing scheme to maximize the efficiency of voice packet transmission over an OLPC mesh network.

Future Work

In the future, we plan to explore algorithms to optimally utilize available memory and achieve maximum efficiency in the transmission of voice data. We also plan to apply what we learn towards developing a collaborative musical activity on the laptop that will exploit the mesh network.

For more information:
OLPC: www.laptop.org
Source of Images: www.laptop.org