Data Logging : Interface

The sensors that are used in a data logging system are not plugged directly into the computer. This is because :

• Some of the sensors produce analogue voltages which can not be processed by the computer. These voltages need to be changed into digital signals (0s and 1s) before the computer can process them.
• The computer could be damaged if the voltages that the sensors sent to it became too large.

An interface is put between the sensors and the computer. You can typically connect up to eight sensors to an interface made for a home computer. The interface converts the voltages that the sensors produce into digital signals that the computer can process and protects the computer from dangerous voltages.

The conversion is carried out by a special device inside the interface which is known as an analogue-to-digital convertor or ADC.

GCSE ICT Companion 04 - (C) P Meakin 2004