Physics for Game Developers, 2nd Edition

Chapter 23. Pressure Sensors and Load Cells

Pressure sensors are an evolution of the simple button. A simple button has two states, on or off, which can be used to trigger simple atomic actions in a video game such as firing a gun or opening a door. However, simple buttons are not capable of informing the program how you, the user, hits that button. Did you hit it quickly? Did you barely touch it at all? The only thing the program can interpret is that you did in fact hit the button.

With pressure sensors, the program has the ability to discern how the user pressed the button. This information can be used as incremental input, such as the player raising a firearm before pressing the button harder to actually fire. Additionally, pressure sensors can be used to create novel forms of human-input devices. While pressure sensitivity is not uncommon in the more traditional console gaming markets, there is also a recent push to move the sensors into touch-screen devices like the Nintendo DS and cell phone gaming market. Pressure-sensitive touch screens are currently beyond state of the art, however, so we’ll primarily discuss the traditional methods already in widespread adoption.

In addition to pressure sensors, some new gaming consoles use load cells to allow the player to use shifts in his or her body weight as input. The method by which this data is collected and how the center of gravity is determined will be discussed in this chapter. Lastly, some smartphones now include a barometer ...