The HP203B is an absolute pressure sensor capable of directly converting pressure to altitude. Therefore, you don't need to write a piece of code to convert from pressure to altitude. Neat!

This board comes with a built-in 3.3V regulator and level shifter. This means that you can use it both with 5V and 3.3V microcontrollers.

Some specs: - Altitude range from -1400 to 9000 m (300 to 1200 mbar) - Temperature range from -40 to 85 C - Altitude resolution 10 cm - Temperature resolution 0.01 C - Serial data clock frequency 400 kHz

I have measured the altitude noise at different oversampling rates (OSR). Even though this does not come close in noise level and measurement speed to the admirable MS5637 that I used in my Rockit flight computer it costs about 10 times less. Thus, it is ideal for applications where a rough measurement of altitude is sufficient.

You can find from my GitHub repository Arduino code that allows you to use the sensor without libraries. You can also adjust the OSR to suit your needs. See the pictures in the page to see how the OSR impacts the measurement noise and time.

The package includes a fully assembled and tested HP203B evaluation board and separate pin headers. You can change the I2C address of the sensor from 0x76 to 0x77 by soldering the jumper located underneath the board. The pinout of the sensor is easily accessible allowing you to use interrupt pins 0 and 1 (INT0, and INT1). These pins toggle HIGH and LOW depending on whether the temperature and altitude (pressure) readings are complete. This feature is useful for example to indicate a microcontroller that data are ready to be read.