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.
Three weeks to a month is a safe interval for following up on a blind ad. A short email indicating your continuing interest in the position may get a response, especially since few applicants bother to pursue the job beyond sending a resume. Potential employers appreciate enthusiasm and perseverance. Most job seekers miss an important opportunity when they worry about being overeager.