I want to make a line follower robot. When i use qtr library this sensor not showing any value on serial monitor…but if i use only raw value library it shows output on serial monitor…How can i solve it?
Unfortunately, the board in your picture is not a genuine Pololu product, and we can not offer support for it or guarantee that our libraries will work correctly with it.
If you want to try a genuine Pololu QTR sensor, then you can find them on our website, or you can get them from our authorized distributors.
Brandon