Using software serial on ESP8266
Posted: Fri Mar 29, 2019 6:37 pmI am trying to interface the Adafruit fingerprint sensor with the ESP8266 module through the Arduino IDE. Originally I had the sensor connected to an Arduino Uno and set up with software serial at 9600 baud which worked fine. Now, I want to connect this project to Node-RED running on an Amazon webserver. My issue is when trying to move my code to the ESP8266 module the software serial on the ESP8266 module no longer detects the sensor. From what I have gathered online this could be because the baud rate on the module is set at 115200 baud by default and this is questionably supported, if at all, by the default software serial. I am wondering what the correct approach would be to implement 'software serial' on an ESP8266 module to work with my purposes. I have heard people using AT commands to change the baud rate down to 9600 but some of the commands bricked their devices so I have been hesitant to try this yet. Below I have pasted the code that I currently have. This is my first post so if you need anymore information to help, I'll add it as necessary. Thanks,
Code: Select all
/***************************************************
This code runs on the MCU to allow or deny access via LED control signals
****************************************************/
//
#include <Adafruit_Fingerprint.h> //include Adafruit sensor libraries
#include <SoftwareSerial.h>
SoftwareSerial mySerial(12, 13, false, 256); // Sets up software serial to be used by pins #12 (Rx) and #13 (Tx)
Adafruit_Fingerprint finger = Adafruit_Fingerprint(&mySerial);
//Buzzer
const int buzzPin = 16; //Pin for buzzer
const int RLEDPin = 0; //Pin for Red LED
const int GLEDPin = 13; //Pin for green LED
const int YLEDPin = 15; //Pin for yellow LED
const int ConfThres = 300; //Confidence threshold (Increasing this will cause sensor to be more secure)
void setup()
{
pinMode(0,OUTPUT);
pinMode(13,OUTPUT);
pinMode(15,OUTPUT);
Serial.begin(9600); //Begins serial communication at 9600 baud
while (!Serial);
delay(100);
Serial.println("\n\nFingerprint Sensor detection test"); //Prints sensor detect test
finger.begin(57600); // set the data rate for the sensor serial port
//Scans to see if the fingerprint sensor can be found
if (finger.verifyPassword()) { //Verifies password set in fingerprint sensor
Serial.println("Fingerprint sensor has been found"); //if fingerprint sensor is found
} else {
Serial.println("Did not find fingerprint sensor, please reset"); //Print error if fingerprint sensor is not found
digitalWrite(RLEDPin,HIGH); //RED LED on if no sensor found
while (1) { delay(1); }
}
finger.getTemplateCount(); //Function to get the number of fingerprints stored(up to 162)
Serial.print("Sensor contains "); //Print the number of fingerprints stored
Serial.print(finger.templateCount);
Serial.println(" fingerprints");
Serial.println("Waiting for valid fingerprint..."); //Next loop waits for a valid fingerprint
}
void loop() //Continue Running loop
{
if(getFingerprintIDez()>=ConfThres){ //if valid fingerprint confidence is above threshold, buzz 'correct sound'
buzzer(true);
}
delay(50); //Slows down the loop from running full speed
}
//This function captures the fingerprint image
uint8_t getFingerprintID() {
uint8_t p = finger.getImage(); //.getImage() is the function used by the DSP chip to capture the fingerprint
switch (p) {
case FINGERPRINT_OK:
Serial.println("Image taken");
break;
case FINGERPRINT_NOFINGER:
Serial.println("No finger detected");
return p;
case FINGERPRINT_PACKETRECIEVEERR:
Serial.println("Communication error");
return p;
case FINGERPRINT_IMAGEFAIL:
Serial.println("Imaging error");
return p;
default:
Serial.println("Unknown error");
return p;
}
// OK success!
//This function converts the image and looks for features in the scanned print to be compared with the fingerprints stored in the data base
p = finger.image2Tz(); //.image2Tz is the function used by the DSP chip
switch (p) { //Case test to test if the image was correctly decoded or tests a set of errors
case FINGERPRINT_OK: //Tests case if the fingerprint was ok
Serial.println("Image converted"); //Print corresponding message
break;
case FINGERPRINT_IMAGEMESS: //Tests case if the image was to noisy
Serial.println("Image too noisy"); //Print corresponding message
return p;
case FINGERPRINT_PACKETRECIEVEERR: //Tests case if there was a communication error with the sensor
Serial.println("Communication error"); //Print corresponding message
return p;
case FINGERPRINT_FEATUREFAIL: //Tests case if no valid features were found with scanned fingerprint
Serial.println("Could not find fingerprint features"); //Print corresponding message
return p;
case FINGERPRINT_INVALIDIMAGE: //Tests case if no valid features were found with scanned fingerprint
Serial.println("Could not find fingerprint features"); //Print corresponding message
return p;
default: //Else:
Serial.println("Unknown error"); //Print corresponding message
return p;
}
//Continue if "Image Converted"
p = finger.fingerFastSearch();
if (p == FINGERPRINT_OK) { //If scanned fingerprint features match that a saved fingerprint
Serial.println("Found a print match!"); //Print that a match was found
} else if (p == FINGERPRINT_PACKETRECIEVEERR) { //If there was a communication error
Serial.println("Communication error"); //Print there was a comm error
return p;
} else if (p == FINGERPRINT_NOTFOUND) { //If scanned fingerprint does not match a saved fingerprint
Serial.println("Did not find a match"); //Print that no match was found
return p;
} else {
Serial.println("Unknown error"); //Else: Print unknown error
return p;
}
// found a match!
Serial.print("Found ID #"); Serial.print(finger.fingerID); //If a match was found, print the ID of the fingerprint
Serial.print(" with confidence of ");
Serial.println(finger.confidence); //Calculates the confidence of the compared images
return finger.fingerID;
}
// returns -1 if failed, otherwise returns ID #
int getFingerprintIDez() {
uint8_t p = finger.getImage(); //p = fingerprint image
if (p != FINGERPRINT_OK) return -1; //If fingerprint not recognized function returns -1
p = finger.image2Tz(); //Calls .image2Tz function
if (p != FINGERPRINT_OK) return -1;
p = finger.fingerFastSearch(); //Calls .fingerFastSearch function
if (p != FINGERPRINT_OK) return -1;
// found a match!
if(finger.confidence<ConfThres) //if confidence of fingerprint is less than set threshold, buzz 'false tone'
buzzer(false);
digitalWrite(YLEDPin,LOW); //Turns off Yellow LED when match is found
delay(1000);
digitalWrite(YLEDPin,HIGH); //Turn on yellow LED signaling Fingerprint sensor is ready to scan fingerprint
Serial.print("Found ID #");
Serial.print(finger.fingerID); //Print fingerprint ID
Serial.print(" with confidence of ");
Serial.println(finger.confidence); //Print confidence of fingerprint scan
return finger.confidence; //return from function
}
void buzzer(boolean valid){
if(valid){ //if fingerprints matched,
digitalWrite(GLEDPin,HIGH); //Turns on Green LED when match is found
delay(1000);
digitalWrite(GLEDPin,LOW);
tone(buzzPin, 523, 200); //buzz 'correct tone'
}
else if(!valid){ //else if invalid
digitalWrite(RLEDPin,HIGH); //turn on red LED for some time
delay(1000);
digitalWrite(RLEDPin,LOW);
tone(buzzPin, 123, 600); //buzz 'incorrect tone'
}
}