Sensors are not working properly(sensor 1 and sensors 8)

I am using QTR-8 reflectance array for my LFR but having trouble with RAW values. When some of the sensors are on white line and other on different color line, i should get different raw values but all are giving same raw values (approx). please help ASAP. The code i m using is an example of QTRsensors library.


Are sensors 1 and 8 the only two that are behaving this way, or do they all do the same thing? How far away are your QTR sensors from the surface? Could you post an example of the values your sensors are returning here?

These sensors use IR light to detect the surface and it is not always obvious from the appearance of an object how it will reflect IR light. If you are using different colors instead of black and white surfaces, the sensors might not show any difference. You might try to test all of the sensors over your colored surface and then test them all over the white surface to see if all of the sensors behave consistently over the same surfaces and different over the contrasting surfaces you are using.