Adafruit Industries 992

This Freescale pressure sensor is a low-cost sensing solution for measuring atmospheric pressure. Its resolution is 1.5 hPa, which is less accurate than the BMP085 with a resolution of up to 0.03 hPa, so it is not recommended for use as a precision altimeter. However, it is well-suited for basic atmospheric pressure sensing. The sensor is soldered onto a PCB with 10K pull-up resistors on the I2C pins. This chip supports supply and logic voltages from 2.4V to 5.5V, making it compatible with both 3V and 5V microcontrollers. The chip includes a basic internal temperature sensor, but no specifications are provided in the datasheet, so its accuracy is uncertain. This chip looks and sounds very similar to the MPL3115A2, but it is a lower-accuracy version intended only for atmospheric pressure sensing. Using this sensor is straightforward. For example, with an Arduino, simply connect the VDD pin to the 5V power pin, GND to ground, SCL to the I2C clock (analog pin 5 on the UNO), and SDA to the I2C data (analog pin 4 on the UNO). Then download the Arduino library for the MPL115A2 along with the example code for temperature, pressure, and basic altitude calculations. Install the library and load the example sketch to immediately view temperature, pressure, and altitude data in the serial console.