Audio hardware

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HowTo [ID# 45051]  +/-

These are ideas related to both audio input and output. Please review the hardware specification to see what is already included. Some audio-related ideas are also dealt with in the Radio and Broadcast page.

Microphone

A built in Microphone would be usefully if dirt and echo/feedback could be controlled. If you have a microphone and speakers included with these laptops then then if you include a small peice of software they can be used as telephones or walkitalkies -- like an instant message local channel that is as easy to use as a CB radio. If the hardware looked like a radio, the oporator could use it before they learend how to use the computer.

Sound Codec

The [Hardware specification]] page says the Audio Codec is an Analog Devices AD1888, AC97-compatible audio codec.

The paper - 'The One Laptop per Child (OLPC) Audio Subystem' by Jaya (Alsa) provides useful information on the audio subsystem. The link is - [www.kgw.tu-berlin.de/~lac2007/papers/lac07_kumar.pdf The OLPC Audio Subsystem]

Microphone Sensor Input

The microphone input can be used to measure voltage or (using the Microphone bias voltage) resistance. This should enable us to use this as a form of sensor input with the audio analog to digital converter converting the sensor signal to a signal that can be displayed on the screen or logged by the computer. More info is required on the use of the codec in this mode.

• max voltage that can be withstood safely by the mic input
• Voltage corresponding to AD converter full scale.
• Bias voltage output (open circuit)
• Bias voltage output (short circuit)
• anything else?

Microphone data input

The microphone input jack can double as a dataport for some class of devices (when supporting a "DC-coupled" input mode), but a more general-purpose USB analog to digital device would be a great peripheral for the laptop. --Walter

It has been suggested that this article or section be merged with [[:{{{1}}}|{{{1}}}]]. (Discuss)