Reported May 2008

COMPUTERS IN YOUR CAR: All modern cars have a computer in charge of monitoring various systems. This central computer receives information from a collection of sensors that monitor things like oxygen, air pressure, air temperature and engine temperature, to name a few. Using this information, the computer can control the car's parts to get the best performance from the engine while keeping emissions low.

HOW DO SENSORS WORK? How sensors work depends on whether they are pressure-sensitive or light-sensitive. A pressure-sensitive device can sense changes in pressure and emits an appropriate voltage in response to correct problems. These sensors are used in braking systems and collision avoidance systems, for example. Light-sensitive, or optical sensors work very much like the wireless mouse technology in desktop computer systems. A small diode bounces light off a surface, onto a sensor, to form images. The sensor sends the data to a digital signal processor for analysis. This processor can detect patterns in the images and figure out how they have changed since the previous image it received from the sensor. Based on the changes in patterns over time, the processor can determine how far the mouse or car, for example, has moved. It can then send electrical signals to the central computer to trigger the appropriate response.

OTHER NEW APPLICATIONS FOR SENSORS: Sensors can scan the precise position of the driver's eye level and adjust the seat accordingly. Newer prototype cars include infrared light enhancers to improve night vision, as well as rearview mirrors and rear bumper sensors to alert the driver when other vehicles are approaching the car's blind spot. Adaptive headlamps contain sensors that monitor a car's speed and steering wheel movements and adjust lighting accordingly. For example, at high speeds, light beams are given a longer reach. Remain-in-lane systems use forward-facing cameras to monitor the car's position in relation to the road's centerline and side marker lines for 20 meters ahead of the car. If the car begins to veer out of the lane, the sensors detect this and set off a warning sound.

The Human Factors and Ergonomics Society contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Human Factors and Ergonomics Society
Santa Monica, CA 90406
(310) 394-1811
http://www.hfes.or

Nick Kelling
Georgia Institute of Technology
(404) 385-4629 (office)
nicholas.kelling@psych.gatech.edu