If you want to check if r303 | Projects › Projects › Communicating with R303A fingerprint reader module › If you want to check if r303 April 11, 2014 at 12:51 pm #11532 DronaParticipant If you want to check if r303 module works then connect its vcc to 5v and gnd to gnd. immediately after connecting gnd Immediately light will glow on and off(that on and off is fraction of sec). that means that r303 is working. Then comming to open device error try removing and trying againg.
