This disclosure is directed to devices, integrated circuits, and methods for sensing radiation. In one example, a device includes an oscillator, configured to deliver a signal via an output at intervals defined by an oscillation frequency, and a counter, connected to the output of the oscillator and configured to count a number of times the comparator delivers the output signal. The oscillator includes a radiation-sensitive cell that applies a resistance. The resistance of the radiation-sensitive cell is configured to vary in response to incident radiation, wherein the oscillation frequency varies based at least in part on the resistance of the radiation-sensitive cell.