Serial Port Busy using Fingerprint Scanner with SDK Software

Hey all,

I am using a TTL (GT-521F32) fingerprint scanner with an Arduino Uno. I’m following the introductory tutorial provided by Sparkfun and I’m having issues getting started.

I went to upload this first sample sketch:

It is recommended to use a dedicated bi-direcitonal LLC
[ https://www.sparkfun.com/products/12009 ] for a reliable connection if you
are using a 5V Arduino microcontroller:

   Fingerprint Scanner (Pin #) <-> Logic Level Converter <-> 5V Arduino w/ Atmega328P
     UART_TX (3.3V TTL)(Pin 1) <->     LV1 <-> HV1       <->  RX (pin 4)
     UART_RX (3.3V TTL)(Pin 2) <->     LV4 <-> HV4       <->  TX (pin 5)
           GND         (Pin 3) <->     GND <-> GND       <->     GND
      Vin (3.3V~6V)    (Pin 4) <->        HV             <->      5V
                                          LV             <->     3.3V
  
2.) Voltage Division w/ 3x 10kOhm Resistors

Otherwise, you could use 3x 10kOhm resistors [ https://www.sparkfun.com/products/11508 ]
to divide the voltage from a 5V Arduino down to 3.3V FPS similar to the
"Uni-Directional" application circuit on our old logic level converter
[ https://cdn.sparkfun.com/assets/b/0/e/1/0/522637c6757b7f2b228b4568.png ]:

    Voltage Divider         <-> Fingerprint Scanner(Pin #) <-> Voltage Divider <-> 5V Arduino w/ Atmega328P
                            <-> UART_TX (3.3V TTL) (Pin 1) <->                 <->       RX (pin 4)
  GND <-> 10kOhm <-> 10kOhm <-> UART_RX (3.3V TTL) (Pin 2) <->      10kOhm     <->       TX (pin 5)
          GND               <->        GND         (Pin 3) <->       GND       <->        GND
                            <->    Vin (3.3V~6V)   (Pin 4) <->                 <->        5V
    
Note: You can add the two 10kOhm resistors in series for 20kOhms. =)

--------------------------------------------------------------------------------*/

// set up software serial pins for Arduino's w/ Atmega328P's
// FPS (TX) is connected to pin 4 (Arduino's Software RX)
// FPS (RX) is connected through a converter to pin 5 (Arduino's Software TX)
FPS_GT511C3 fps(4, 5); // (Arduino SS_RX = pin 4, Arduino SS_TX = pin 5)

/*If using another Arduino microcontroller, try commenting out line 59 and
uncommenting line 68 due to the limitations listed in the
library's note => https://www.arduino.cc/en/Reference/softwareSerial . Do
not forget to rewire the connection to the Arduino*/

// FPS (TX) is connected to pin 10 (Arduino's Software RX)
// FPS (RX) is connected through a converter to pin 11 (Arduino's Software TX)
//FPS_GT511C3 fps(10, 11); // (Arduino SS_RX = pin 10, Arduino SS_TX = pin 11)

void setup()
{
 Serial.begin(9600); //set up Arduino's hardware serial UART
 fps.UseSerialDebug = true; // so you can see the messages in the serial debug screen
 fps.Open(); //send serial command to initialize fps
}

void loop()
{
 // FPS Blink LED Test
 fps.SetLED(true); // turn on the LED inside the fps
 delay(1000);
 fps.SetLED(false);// turn off the LED inside the fps
 delay(1000);
}

There is additional software required to use, found here - https://cdn.sparkfun.com/assets/learn_tutorials/7/2/3/20171129-SDK_Demo_Ver1.9.zip

After uploading the sketch, I’m supposed to hit the reset button on the arduino, select the port the Arduino is connected to, and then hit ‘open’ on the software interface. Afterwards, it says to open the Serial Monitor on the IDE, however when I do so it states that the port is busy. Is there something obvious I’m missing here?

Thanks, and I apologize if I didn’t explain that clearly.

After uploading the sketch, I'm supposed to hit the reset button on the arduino, select the port the Arduino is connected to, and then hit 'open' on the software interface.

Open on WHAT software interface?

Afterwards, it says to open the Serial Monitor on the IDE, however when I do so it states that the port is busy. Is there something obvious I'm missing here?

Just that the person that wrote those instructions, if you are reading them correctly, is completely clueless.

PaulS:
Open on WHAT software interface?

https://cdn.sparkfun.com/assets/learn_tutorials/7/2/3/20171129-SDK_Demo_Ver1.9.zip

PaulS:
Just that the person that wrote those instructions, if you are reading them correctly, is completely clueless.

Well it wasn't the latter, I wasn't paying attention... The code was an alternative to the software...