Here, we present detailed instructions on how to build and calibrate research quality ceptometers (light sensors that integrate light intensity across many sensors arrayed linearly along a horizontal bar).
Salter, W. T., Merchant, A. M., Gilbert, M. E., Buckley, T. N. PARbars: Cheap, Easy to Build Ceptometers for Continuous Measurement of Light Interception in Plant Canopies. J. Vis. Exp. (147), e59447, doi:10.3791/59447 (2019).