A digital barometer measures air pressure. It is used to predict future weather in a local region. When combined over a country, they are used for national weather reports. A high pressure reading indicates good weather and a low pressure reading indicates bad weather. The digital barometer is a cheaper alternative to the aneroid barometer and a safer alternative to the traditional mercury barometer.
Traditional barometers were made using mercury. The mercury was placed in a vertical glass tube. The weight of the atmosphere balances the mercury and forces it to take up more or less space. The sale of mercury was strictly limited by the European Union (EU) in 2007, and as a result, the production of new mercury barometers slowed considerably.
In the 19th century, Lucien Vidie, a Frenchman, created the aneroid barometer. This barometer is the direct inspiration for the digital barometer and the analog electrical aneroid barometers. A spring-balanced capsule, within a sealed unit inside the aneroid barometer, swells and contracts depending upon the air pressure outside. This triggers a series of chains and levers, which alter the reading on the barometer’s interface.
Digital barometers and analog electrical barometers use electrical charges to measure the weight of air above the barometer. An aneroid contraption is too complex for a watch or a car console, so digital barometers are used instead. The simplest digital barometer contains two metal strips within the aneroid capsule. An electrical charge runs between the two strips and measures the distance between them, sending the results to the digital screen. This removes the need for the levers and chains present in typical aneroid barometers.
A modern digital barometer uses digital capacitors to produce a reading. The capacitor uses composite sensing and flexible plates to produce a readout. Rather than being sent as an analog or indiscreet signal, the electrical signal is sent discreetly. Such discreet signals are called ‘digital signals’ and are being used more frequently for radio and television broadcasts.
The digital barometer is used like other barometers to predict the weather. A slow rise in air pressure means there is a long spell of good weather ahead. A sudden drop indicates a brief storm will arrive in around five hours. Slow drops can indicate a spell of cold, windy and rainy weather. Slow and regular drops can also indicate that a storm is passing nearby; the storm weather will not affect the barometer’s region, but has lowered the air pressure.
With the advent of small technology and digital signals, barometers are found in more and more places. This includes on mantelpieces, walls, cars and even watches. Watch barometers are affected by body heat, so individuals wearing them should hold the watch away from the skin when looking for an accurate barometer reading.