So i know this post is nearly a year old, but i'm facing the same problem today I try to use a Fingerprint Sensor (FPS) with the BlueBean. Works well with Adafruit Trinket Pro 3V (12MHz) but fails with Bean.
When i use pins A0 and A1 like @david2 instead it works well. seems to be a problem with the implementation of SoftwareSerial or the digital pins.
i basically use the blink-example sketch from the FPS Library on Github
FPS_Enroll.ino - Library example for controlling the GT-511C3 Finger Print Scanner (FPS)
Created by Josh Hawley, July 23rd 2013
Licensed for non-commercial use, must include this license message
basically, Feel free to hack away at it, but just give me credit for my work =)
TLDR; Wil Wheaton's Law
This simple sketch turns the LED on and off similar to the Arduino blink sketch.
It is used to show that communications are working.
// Hardware setup - FPS connected to:
// digital pin 4(arduino rx, fps tx)
// digital pin 5(arduino tx - 560ohm resistor fps tx - 1000ohm resistor - ground)
// this brings the 5v tx line down to about 3.2v so we dont fry our fps
//FPS_GT511C3 fps(4, 5); //doesn't work, sends data but never receive.
FPS_GT511C3 fps(A0, A1); //works
fps.UseSerialDebug = true; // so you can see the messages in the serial debug screen
// FPS Blink LED Test
fps.SetLED(true); // turn on the LED inside the fps
fps.SetLED(false);// turn off the LED inside the fps