Some of you may remember me from my old, incredibly botched code, found here: forum.arduino.cc/index.php?topic=603444.0
I started a different, more imperative project, so I left of on this for a while. I did not gain any new Arduino information, but I did learn how to use Imagej and ffmpeg, so that's a plus 
. I am currently using an Arduino mega2560 (through COM7), with Arduino IDE 1.8.8, on windows 7. I am using the ID-20LA Innovations RFID reader.
Coming back to this project has left me completely lost. I found an example script which may work better for my purposes than my old, broken code:
/*
Software serial multiple serial test
Receives from the two software serial ports,
sends to the hardware serial port.
In order to listen on a software port, you call port.listen().
When using two software serial ports, you have to switch ports
by listen()ing on each one in turn. Pick a logical time to switch
ports, like the end of an expected transmission, or when the
buffer is empty. This example switches ports when there is nothing
more to read from a port
The circuit:
Two devices which communicate serially are needed.
* First serial device's TX attached to digital pin 10(RX), RX to pin 11(TX)
* Second serial device's TX attached to digital pin 8(RX), RX to pin 9(TX)
Note:
Not all pins on the Mega and Mega 2560 support change interrupts,
so only the following can be used for RX:
10, 11, 12, 13, 50, 51, 52, 53, 62, 63, 64, 65, 66, 67, 68, 69
Not all pins on the Leonardo support change interrupts,
so only the following can be used for RX:
8, 9, 10, 11, 14 (MISO), 15 (SCK), 16 (MOSI).
created 18 Apr. 2011
modified 19 March 2016
by Tom Igoe
based on Mikal Hart's twoPortRXExample
This example code is in the public domain.
*/
#include <SoftwareSerial.h>
// software serial #1: RX = digital pin 10, TX = digital pin 11
SoftwareSerial portOne(10, 11);
// software serial #2: RX = digital pin 8, TX = digital pin 9
// on the Mega, use other pins instead, since 8 and 9 don't work on the Mega
SoftwareSerial portTwo(8, 9);
void setup() {
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
// Start each software serial port
portOne.begin(9600);
portTwo.begin(9600);
}
void loop() {
// By default, the last intialized port is listening.
// when you want to listen on a port, explicitly select it:
portOne.listen();
Serial.println("Data from port one:");
// while there is data coming in, read it
// and send to the hardware serial port:
while (portOne.available() > 0) {
char inByte = portOne.read();
Serial.write(inByte);
}
// blank line to separate data from the two ports:
Serial.println();
// Now listen on the second port
portTwo.listen();
// while there is data coming in, read it
// and send to the hardware serial port:
Serial.println("Data from port two:");
while (portTwo.available() > 0) {
char inByte = portTwo.read();
Serial.write(inByte);
}
// blank line to separate data from the two ports:
Serial.println();
}
so I have a couple of questions.
-
How would I go about expanding this code to include 8 or more RFID readers per arduino? Is that even possible?
-
My old code included a reset pin for the RFID readers. Must I include that in this new script? If so, can I just do a copy&paste, including the void setup info, or must something new be written?
-
Since I am using the mega, there is only certain pins that work, so 8 and 9 are out. I am opting for pins (50, 51). Since my RFID readers only transmit read tags, do I put the pins into the RX or TX pins? Is there anything that I put into the TX pin? Am I completely confusing the two?
-
related to the above, the description switches around RX and TX multiple times, so I am unsure about where exactly each one goes. Is it possible to for someone to draw up a correct wiring diagram for me?
As of now, the code runs, and outputs the strings "Data from..." into the serial monitor. However, holding an RFID tag to the readers does not change the output at all. What am I missing?
