J-M-L:
Do you understand this comment at the beginning of the code// [color=red]Software serial for when you dont have a hardware serial port[/color]
// pin #2 is IN from sensor (GREEN wire)
// pin #3 is OUT from arduino (WHITE wire)
// On Leonardo/Micro/Yun, use pins 8 & 9. On Mega, just grab a hardware serialport
SoftwareSerial mySerial(10, 11);
They also sent say// On Leonardo/Micro or others with hardware serial, use those! #0 is green wire, #1 is white
//Adafruit_Fingerprint finger = Adafruit_Fingerprint(&Serial1);How is your sensor connected?
I already try that comment too, but it didn't work.