IRCF360 - Zones
The value of BYTE2 can influence the sensitivity of the infrared proximity sensing. The default value is 10 which influences the carrier frequency / modulation frequency of the IR LED's, which is set approximately 37.5 KHz.
According to the data-sheet from the infrared sensor's manufacture, the most sensitive carrier frequency is at 38 KHz. The graphs show that if the carrier frequency is increased to 36KHz or reduced to 40KHz the sensitivity is reduced to only 50% as sensitive as it would be at 38 KHz.
By adjusting the carrier frequency slightly it possible to adjust the sensitivity of the sensors. This is sometimes a good thing, especially if the sensitivity is too high at close distances. Also by adjusting the sensitivity of the IR sensor in this way it is possible to filter in/out specific proximity readings. For example by increasing the sensitivity of the IRCF360 more ground reflection is detected, which is normally undesirable unless of course this information is used to detecting edges of tables or table boarders designated by black taped areas..
By experimenting with different values it is possible to find a combination of frequencies that work best for your own specific project.