BMP180 is a Digital pressure sensor. In this tutorial we are interfacing BMP180 with ESP8266. Sensor have pressure range of 300 to 1100hPa and operate at 1.8V to 3.6V. It’s common application is Weather forecast.
How BMP180 used for weather forecast?
In order to understand the types of weather conditions generally associated with high and low pressure systems, we must think “vertically.” The motion of air in the atmosphere above our heads plays a large part in the weather we experience here at earth’s surface. Basically, air cools as it rises, which can cause water vapor in the air to condense into liquid water droplets, sometimes forming clouds and precipitation. On the other hand, sinking air is associated with warming and drying conditions. So the first important point to keep in mind is rising air = moistening, sinking air = drying. So what does this have to do with high and low pressure? Well, high pressure is associated with sinking air, and low pressure is associated with rising air. But why? The answer has to do with the typical air flow around high and low pressure. Physically, it seems to make sense to have air flow from high pressure to low pressure. For reasons I won’t get into in this post, the airflow (due to the Earth’s rotation and friction) is directed slightly inward toward the low pressure center, and slightly outward away from the high pressure center: The slightly inward moving air in low pressure causes air to converge and since it can’t move downward due to the surface, the air is forced upward, leading to condensation and precipitation as discussed earlier. The opposite occurs with high pressure. Air is moving away from the high pressure center at the surface (or “diverging”) so as a result, air from above must sink to take its place. The surface flow is accompanied by the opposite behavior at upper levels of the atmosphere, as depicted in this schematic diagram: