A power drive unit (PDU) includes a light source configured to generate light as pulses with pulse intervals between the pulses. The PDU also includes a light driver configured to control the light source to generate the light at a desired intensity. The PDU also includes a light receiver configured to receive a reflection of the light. The PDU also includes a processor coupled to the light receiver and configured to determine whether the cargo is positioned on the PDU based on the reflection of the light. The PDU also includes a light controller coupled to the processor and the light driver and configured to determine an adjustment to the desired intensity of the light generated by the light source based on an intensity of the reflection of the light and whether the light source is generating a pulse or a pulse interval.