Small pressure sensors

In addition to the wonderful world of 9-axis motion sensors there is a 10th degree of freedom commonly added to the the other nine: altitude or height. The altitude is measured with a pressure sensor or altimeter, where the absolute pressure is converted to a local (relative) altitude. Like their motion sensing counterparts, pressure sensors have been getting smaller, cheaper, higher in resolution, and easier to use. I want to compare and contrast some relatively new pressure sensors to get an idea of the current state-of-the-art and what these pressure sensors can do. The technology is evolving rapidly, yet the products introduced within the last year make low-power, portable (aka wearable), high-resolution altimetry very easy to achieve. Here is a comparison between three pressure sensors firmly in the portable category:

Table 1 Pressure sensors from Freescale Semiconductor, Measurement Specialties, and ST Microelectronics illustrate what is possible today.

These aren't the only or best choices, but they are representative of offerings from three leading manufacturers and the table illustrates the trade-off users might have to make. I will discuss each attribute. Here is what the packages look like:

The three pressure sensors come in progressively smaller packages.