I am using the above board nodemcu v0.9.
D1 &D2 for I2C, D7 one WIRE , D5 D6 as OUTPUTS.
My problem is D0,D3,D4 ,or D8 i cannot get to work as input or output.
What am i doing wrong.This may not be a problem with BLYNK .
What is the maximum I/O .
D3, D4 & D8 correspond to GPIO 0, 2 and 15, these IO pins are used for programming and bootloader operations. D0 corresponds to GPIO 16 which can be used to wake up the board from deep sleep. Best to avoid using these for general IO.