Yeah, we need a BUNCH more information:
- When you say "Distance Measurement", why kind of measurement? Precise? Rough? Distance vs NOT Distance?
- Distance in thin air? Across some surface? What kind of surface? Always the same kind of surface, or different surfaces [i.e. unknown target]? From a static position? ...or, While the electronics are moving? While the mystery target is moving? or Both? Something else I didn't think of? Or, maybe the question is better asked as "Distance between what and what?"
- And, even more informative would be a description of what you want to achieve. When you say you need to build this circuit, do you mean this is something like a school project, or have you been captured by a mad scientist, and measuring distance has something to do with an escape plan, and these components you listed are all that is available in this secluded lab?