Here's an app to tell you when to have coffee.

Caffeinated drinks such as coffee and soda are the pick-me-ups of choice for many people, but too much caffeine can cause nervousness and sleep problems.

Caffeine Zone, a software app developed by Penn State researchers, can help people determine when caffeine may give them a mental boost and when it could hurt their sleep patterns. The software takes information on caffeine use and integrates it with information on the effects of caffeine to produce a graph of how the caffeine will affect the users over time.