I am altering a program to run an RFID.
The program has many Serial.print instructions
They are all in the format Serial.print(F(“string”))
The learning section on this site says
You can pass flash-memory based strings to Serial.print() by wrapping them with F(). For example :
here
about twenty lines from the top.
Can someone tell me more information about this or point me to somewhere which explains the reasoning ?
I have been trying to find where in the program the information to the monitor shows a “7” at the start of the first line?
I have posted just down to the bottom of the setup, much more and I exceeded the 9000 character limit.
fairly high up in the setup is the following line that looks like the first thing printed
Serial.println(F(“Access Control v3.3”)); // For debugging purposes
this is the first thing to appear when I click on the monitor button but it is preceded by a 7 ? Why?
/*
Arduino RFID Access Control
Security !
Copyright (C) 2015 Omer Siar Baysal
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <EEPROM.h> // We are going to read and write PICC's UIDs from/to EEPROM
#include <SPI.h> // RC522 Module uses SPI protocol
#include <MFRC522.h> // Library for Mifare RC522 Devices
/*
Instead of a Relay maybe you want to use a servo
Servos can lock and unlock door locks too
There are examples out there.
*/
// #include <Servo.h>
/*
For visualizing whats going on hardware
we need some leds and
to control door lock a relay and a wipe button
(or some other hardware)
Used common anode led,digitalWriting HIGH turns OFF led
Mind that if you are going to use common cathode led or
just seperate leds, simply comment out #define COMMON_ANODE,
*/
//#define COMMON_ANODE
#ifdef COMMON_ANODE
#define LED_ON LOW
#define LED_OFF HIGH
#else
#define LED_ON HIGH
#define LED_OFF LOW
#endif
#define redLed 7 // Set Led Pins
#define greenLed 6
#define blueLed 5
#define relay 4 // Set Relay Pin
#define wipeB 3 // Button pin for WipeMode
boolean match = false; // initialize card match to false
boolean programMode = false; // initialize programming mode to false
int successRead; // Variable integer to keep if we have Successful Read from Reader
byte storedCard[4]; // Stores an ID read from EEPROM
byte readCard[4]; // Stores scanned ID read from RFID Module
byte masterCard[4]; // Stores master card's ID read from EEPROM
/*
We need to define MFRC522's pins and create instance
Pin layout should be as follows (on Arduino Uno):
MOSI: Pin 11 / ICSP-4
MISO: Pin 12 / ICSP-1
SCK : Pin 13 / ICSP-3
SS : Pin 10 (Configurable)
RST : Pin 9 (Configurable)
look MFRC522 Library for
other Arduinos' pin configuration
*/
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
///////////////////////////////////////// Setup ///////////////////////////////////
void setup() {
// Setting Auto Read Mode - EM4102 Decoded Mode - No password
// command: FF 01 09 87 01 03 02 00 10 20 30 40 37
Serial.write(0xFF); //Header
Serial.write(0x01); //Reserved
Serial.write(0x09); //Length (Command + Data)
Serial.write(0x87); //Command (0x87 sets auto mode behavior
Serial.write(0x01); //Data 1: Enable Auto-Read
Serial.write(0x03); //Data 2: Mode – Parity decoded – Manchester RF/64
Serial.write(0x02); //Data 3: Total number of block to be read (2)
Serial.write((byte)0x00); //Data 4: No password expected
Serial.write(0x10); //Data 5: Password byte 1
Serial.write(0x20); //Data 6: Password byte 2
Serial.write(0x30); //Data 7: Password byte 3
Serial.write(0x40); //Data 8: Password byte 4
Serial.write(0x37); //Checksum
delay(500);
//Arduino Pin Configuration
pinMode(redLed, OUTPUT);
pinMode(greenLed, OUTPUT);
pinMode(blueLed, OUTPUT);
pinMode(wipeB, INPUT_PULLUP); // Enable pin's pull up resistor
pinMode(relay, OUTPUT);
//Be careful how relay circuit behave on while resetting or power-cycling your Arduino
digitalWrite(relay, HIGH); // Make sure door is locked
digitalWrite(redLed, LED_OFF); // Make sure led is off
digitalWrite(greenLed, LED_OFF); // Make sure led is off
digitalWrite(blueLed, LED_OFF); // Make sure led is off
//Protocol Configuration
Serial.begin(9600); // Initialize serial communications with PC
SPI.begin(); // MFRC522 Hardware uses SPI protocol
mfrc522.PCD_Init(); // Initialize MFRC522 Hardware
//If you set Antenna Gain to Max it will increase reading distance
//mfrc522.PCD_SetAntennaGain(mfrc522.RxGain_max);
Serial.println(F("Access Control v3.3")); // For debugging purposes
ShowReaderDetails(); // Show details of PCD - MFRC522 Card Reader details
//Wipe Code if Button Pressed while setup run (powered on) it wipes EEPROM
if (digitalRead(wipeB) == LOW) { // when button pressed pin should get low, button connected to ground
digitalWrite(redLed, LED_ON); // Red Led stays on to inform user we are going to wipe
Serial.println(F("Wipe Button Pressed"));
Serial.println(F("You have 5 seconds to Cancel"));
Serial.println(F("This will be remove all records and cannot be undone"));
delay(5000); // Give user enough time to cancel operation
if (digitalRead(wipeB) == LOW) { // If button still be pressed, wipe EEPROM
Serial.println(F("Starting Wiping EEPROM"));
for (int x = 0; x < EEPROM.length(); x = x + 1) { //Loop end of EEPROM address
if (EEPROM.read(x) == 0) { //If EEPROM address 0
// do nothing, already clear, go to the next address in order to save time and reduce writes to EEPROM
}
else {
EEPROM.write(x, 0); // if not write 0 to clear, it takes 3.3mS
}
}
Serial.println(F("EEPROM Successfully Wiped"));
digitalWrite(redLed, LED_OFF); // visualize successful wipe
delay(200);
digitalWrite(redLed, LED_ON);
delay(200);
digitalWrite(redLed, LED_OFF);
delay(200);
digitalWrite(redLed, LED_ON);
delay(200);
digitalWrite(redLed, LED_OFF);
}
else {
Serial.println(F("Wiping Cancelled"));
digitalWrite(redLed, LED_OFF);
}
}
// Check if master card defined, if not let user choose a master card
// This also useful to just redefine Master Card
// You can keep other EEPROM records just write other than 143 to EEPROM address 1
// EEPROM address 1 should hold magical number which is '143'
if (EEPROM.read(1) != 143) {
Serial.println(F("No Master Card Defined"));
Serial.println(F("Scan A PICC to Define as Master Card"));
do {
successRead = getID(); // sets successRead to 1 when we get read from reader otherwise 0
digitalWrite(blueLed, LED_ON); // Visualize Master Card need to be defined
delay(200);
digitalWrite(blueLed, LED_OFF);
delay(200);
}
while (!successRead); // Program will not go further while you not get a successful read
for ( int j = 0; j < 4; j++ ) { // Loop 4 times
EEPROM.write( 2 + j, readCard[j] ); // Write scanned PICC's UID to EEPROM, start from address 3
}
EEPROM.write(1, 143); // Write to EEPROM we defined Master Card.
Serial.println(F("Master Card Defined"));
}
Serial.println(F("-------------------"));
Serial.println(F("Master Card's UID"));
for ( int i = 0; i < 4; i++ ) { // Read Master Card's UID from EEPROM
masterCard[i] = EEPROM.read(2 + i); // Write it to masterCard
Serial.print(masterCard[i], HEX);
}
Serial.println("");
Serial.println(F("-------------------"));
Serial.println(F("Everything Ready"));
Serial.println(F("Waiting PICCs to be scanned"));
cycleLeds(); // Everything ready lets give user some feedback by cycling leds
}