Hardware Reference
In-Depth Information
Infrared sensors
Another type of sensor is a sensor that uses
infrared
(
IR
) signals to detect distance. An IR
sensor also uses both a transmitter and a receiver. The transmitter transmits a narrow beam
of light and the sensor receives this beam of light. The difference in transit ends up as an
angle measurement at the sensor, as shown in the following diagram:
The different angles give you an indication of the distance to the object. Unfortunately, the
relationship between the output of the sensor and the distance is not linear, so you'll need to
do some calibration to predict the actual distance and its relationship to the output of the
sensor. This will be discussed later in this chapter.
