SRM400 Module

hi, i want to measure speed of sound in air. i will use 2 srm400, one for emit pulse and one for receive pulse. i am using this along with a microcontroller dspic30f4013. i want to start timer when pulse sent, and stop timer when pulse is received. then will save timer etc.. my question is: can anybody tell me which timer will be suitable for the srm400? and how to do connections?? thanks in advance for all ur help. ps:its my first time that i am using a transducer