A lightning detector system monitors the lightning strikes requires a real-time detection and processing system. A real-time processing system requires the use of a high-speed processor with floating-point math capability and multiple analog to digital channels. The cost, power and size requirements of such a system make it difficult to develop a low cost, pocket size lightning detector with long battery life. This invention provides a method of detecting and ranging lightning strikes using an inexpensive eight-bit processor with a single A/D channel and without floating point hardware.