US Patent 7800313 Multi-mode LED retrofit module apparatus and method

A multi-mode LED retrofit module is provided for a flashlight of a type having a serious circuit including a battery power supply, a light bulb, and a single pull, single throw rotary on/off switch. The retrofit module includes a logical control device which measures an on/off time of the rotary switch, subsequent to a previous on-time which is greater than a pre-determined threshold. If the subsequent on/off time is less than a pre-determined threshold (preferably 0.5 seconds), the subsequent short on/off cycle is interpreted as an instruction to change mode.