Among other things, a dispensing device is described herein. A sensor component of the dispensing device includes an emitter (e.g., of an emitter array) in optical communication with a detector array for sensing objects disposed between the emitter and the detector array. An object detector is configured to identify a presence of an object between the emitter and the detector array based upon a readout signal generated by the detector array. A calibration component is configured to recalibrate the object detector responsive to determining that an obstruction is present between the emitter and the detector array. The recalibration allows the detector array and the emitter array to detect the presence of an object regardless of the obstruction. A material (e.g., soap, sanitizer, etc.) may be dispensed from the dispensing device responsive to detecting the presence of the object.