Patent ID: 8363887

Claim:
A method to detect the presence of a substance on a test swipe, comprising: in a housing: capturing a background image of the test swipe; applying one or more test chemicals to a test swipe to form sequences of changing color bar codes indicative of the presence of the substance; adjusting the temperature of the test swipe to predetermined temperature ranges and hold times to during automated chemical deposition to provide chemical reactions to form new color bar codes for the substance; controlling a variable speed fan to avoid fogging the camera's lens, to cool after a reaction event and not to cool the reaction at critical reaction time, and to save battery power between sample runs; capturing multiple in-situ images of the test swipe after the application of chemical at the predetermined temperature range; subtracting the background image from the in-situ images; generating a difference value from any two images; and searching a known database to identify the substance based on changing multiple sets of color bar codes generated for unique chemical reaction sequence under specific time and temperature control.