Sensitive Altimeter. This Android application measures air pressure using internal barometric sensor in the portable device and displays it on a three-pointer altitude indicator similar to the altimeter gauge in aircraft. Digital indication is also available.
It can take a long time. Some employers move very quickly, and others move very slowly. People have been hired three hours or three months (or more) after interviewing. Moreover, hiring nearly always takes longer than employers expect it will; you should generally double or triple whatever timeline they give you.
But the good news is, it can be fairly simple to do. The key thing is not to waffle on. Write the presentation out, learn it and time it. Unless they tell you otherwise, a job interview presentation shouldn't last more than 10 minutes.