Infographics don't have to be complicated. This is a very simple, real-world example of an infographic system to monitor the tire pressure on your car called Accu-Pressure Caps. A set of four gauges screw onto your tire's valve stems, and the air pressure pushes the green indicator completely out. As tire pressure begins to drop, so does the green indicator revealing a yellow indicator, and ultimately the red indicator. The key here is to buy the set of caps to match the tire pressure you want to maintain on your car.
An alternative is from aviationupgrade.com, which is a battery operated version. These always start with the tire pressure when you screw them on, and when the pressure drops by 4psi the LED light on the end starts blinking to get your attention.