Hey what im tryin to do is set up tool to measure speed of a moving thing using AVR ATMega. and a pair of infrared to detect the move. it is using assembler language. but using ATMega i can use C language and export it to ASM language. if the infrared device covered by moving device, system will record the time. so we get the time. and then we can calculate the moving speed. sorry of my bad english. Cant get my head around how to do this and any help would be greatly appreciated. thanks