1) Check the present software firmware and the version of Dobot Studio whether they support the color sensor or not.
2) The distance between color sensor and wood blocks shouldn’t be too long or too short, it had better in the range of 5~10 mm.
3) Check the pre-setting color sensor interface and the actual interface is consistent or not.
4) If the above mentioned methods are noneffective, please open the blockly module, and run the test program below. Check the reading data in Running Log which is on the right, and you should change a color sensor if the reading data is abnormal.