Adafruit Industries Adafruit Industries MPL115A2 I2C Barometric Pressure/Temperature Sensor
This pressure sensor from Freescale is a great low-cost sensing solution for measuring barometric pressure. At 1.5 hPa resolution, it's not as precise as our favorite pressure sensor, the BMx280 series, which has up to 0.03 hPa resolution so we don't suggest it as a precision altimeter. However, it's great for basic barometric pressure sensing. The sensor is soldered onto a PCB with 10K pull-up resistors on the I2C pins.
Adafruit Industries MPL115A2 I2C Barometric Pressure/Temperature Sensor
Usually ships in 1-3 business days.