There is not actually code that works that way. There are four sensitivity settings– and you are welcome to play with those exact thresholds in the code –but the sensors are not true distance sensors. Rather, they are designed to detect nearby motion.
In a little more detail: Octolively modules can be used with both active and passive infrared sensing. For the active sensing, where light from the emitters is bounced off of (for instance) your hand and reflected back to the sensors, the range is typically up to 15 cm. If you have strong directional lighting, such as sunlight or an incandescent spotlight, shadows cast on (or moved away from) the sensors will trigger the response. This means that at night, they will have a fairly short range of interactivity, unless you provide an infrared source such as a security spotlight. It also means that an installation can be designed that has range of several meters if you wish.