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.This chip is good for use with power and logic voltages ranging from 2.4V to 5.5V so you can use it with your 3V or 5V microcontroller. There's a basic temperature sensor inside but there's no specifications in the datasheet so we're not sure how accurate it is.This chip looks and sounds a whole lot like the MPL3115A2 but this is the less precise version, best for barometric sensing onlyUsing the sensor is easy. For example, if you're using an Arduino, simply connect the VDD pin to the 5V voltage pin, GND to ground, SCL to I2C Clock (Analog 5 on an UNO) and SDA to I2C Data (Analog 4 on an UNO). Then download our MPL115A2 Arduino library and example code for temperature, pressure and basic altitude calculation. Install the library, and load the example sketch. Immediately you'll have the temperature, pressure and altitude data printed in the serial console.

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 our 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 our 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)

Bosch has stepped up their game with their new BMP280 sensor, an environmental sensor with temperature, barometric pressure that is the next generation upgrade to the BMP085/BMP180/BMP183. This sensor is great for all sorts of weather sensing and can even be used in both I2C and SPI!

This precision sensor from Bosch is the best low-cost, precision sensing solution for measuring barometric pressure with ±1 hPa absolute accuraccy, and temperature with ±1.0°C accuracy. Because pressure changes with altitude, and the pressure measurements are so good, you can also use it as an altimeter with  ±1 meter accuracy.

The BMP280 is the next-generation of sensors from Bosch, and is the upgrade to the BMP085/BMP180/BMP183 - with a low altitude noise of 0.25m and the same fast conversion time. It has the same specifications, but can use either I2C orSPI. For simple easy wiring, go with I2C. If you want to connect a bunch of sensors without worrying about I2C address collisions, go with SPI.

Nice sensor right? So we made it easy for you to get right into your next project. The surface-mount sensor is soldered onto a PCB and comes with a 3.3V regulator and level shifting so you can use it with a 3V or 5V logic microcontroller without worry. We even wrote up a nice tutorial with wiring diagrams, schematics, libraries and examples to get you running in 10 minutes!

And make sure to check the tutorial for example code for Arduino and CircuitPython, pinouts, assembly, wiring, downloads, and more!