Inverse-kinetics is an equation that will calculate the reactivity value for the reactor (in terms of cents). The meter should start when the reactor is critical.
Using Arduino to Create an Online Reactor Reactivity Meter
A Digilent microcontroller board is used to perform inverse-kinetics on an input signal from neutron detectors. Current or pulse detectors can be used, but signal conditioning to obtain a signal of 0-3.3V is required. The setup only works on one range.