eBay - BMP180 Digital Barometric Pressure Sensor Module
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The BMP180 sensor measures absolute pressure. It has a measuring range from 300 to 1100hPa with an accuracy down to 0.02 hPa. It can also measure altitude and temperature.
Learn how to use the BMP180 barometric sensor:
You can compare different temperate sensors to find the best one for your project: DHT11 vs DHT22 vs LM35 vs DS18B20 vs BME280 vs BMP180