This precision sensor from Bosch is the best low-cost sensing solution for measuring barometric pressure and temperature. Because pressure changes with altitude you can also use it as an altimeter! The sensor is soldered onto a PCB with a 3.3V regulator, I2C level shifter and pull-up resistors on the I2C pins.
The BMP180 is the next-generation of sensors from Bosch, and replaces the BMP085. The good news is that it is completely identical to the BMP085 in terms of firmware/software - you can use Adafruit's BMP085 tutorial and any example code/libraries as a drop-in replacement. The XCLR pin is not physically present on the BMP180 so if you need to know that data is ready you will need to query the I2C bus.
This board is 5V compliant - a 3.3V regulator and a i2c level shifter circuit is included so you can use this sensor safely with 5V logic and power.
Using the sensor is easy. For example, if you're using an Arduino, simply connect the VIN pin to the 5V voltage pin, GND to ground, SCL to I2C Clock (Analog 5) and SDA to I2C Data (Analog 4). Then download Adafruit's BMP085/BMP180 Arduino library and example code for temperature, pressure and altitude calculation. Install the library, and load the example sketch. Immediately you'll have precision temperature, pressure and altitude data. Our detailed tutorial has all the info you need including links to software and installation instructions. It includes more information about the BMP180 so you can understand the sensor in depth including how to properly calculate altitude based on sea-level barometric pressure.
BMP180 Barometric Pressure/Temperature/Altitude Sensor- 5V ready (4:40)
- Vin: 3 to 5VDC
- Logic: 3 to 5V compliant
- Pressure sensing range: 300-1100 hPa (9000m to -500m above sea level)
- Up to 0.03hPa / 0.25m resolution
- -40 to +85°C operational range, +-2°C temperature accuracy
- This board/chip uses I2C 7-bit address 0x77.
- Our detailed tutorial has all the info you need including links to software and installation instructions. It includes more information about the BMP180 so you can understand the sensor in depth
- Datasheets, EagleCAD PCB files and Fritzing objects in the tutorial
- Fritzing objects available on GitHub
- EagleCAD PCBs for the BMP085 on GitHub
- EagleCAD PCBs for the BMP180 on GitHub
- BMP180 Datasheet
- BMP085 Datasheet
- Github repository for the 'Unified' sensor driver, inlcuding example code
- Github repository with library and code examples
- Cloud-Connected Weather Station with the Arduino Yun & Temboo
- Adafruit 10-DOF IMU Breakout
- Using the BMP085/180 with Raspberry Pi or Beaglebone Black
- Bosch BMP085 Breakout Board