Abstract
A technique for estimating lung volume change is described. Voltages proportional to rib cage and abdominal hemicircumferences are produced by Whitney-gage transducers in a standard bridge circuit. The weighted sum of these voltages can be adjusted to produce a good estimate of lung volume change. The instrumentation does not obstruct articulatory movements, load the chest wall, or require restraint of the subject. In addition, it is easy and inexpensive to construct.