@bluemanron
1. Connect NANO and mEGA as per following diagram of Fig-1.
Figure-1:
2. Upload the following sketch (your sketch of Post-1 with slight modification) in NANO.
#include<SoftwareSerial.h>
SoftwareSerial SUART(4, 5); //SRX=DPin-4, STX=DPin-5
int rowStatus1 = 0; // Sensor status, with test values
int rowStatus2 = 4; // Sensor status, with test values
int rowStatus3 = 16; // Sensor status, with test values
int rowStatus4 = 0; // Sensor status, with test values
int rowStatus5 = 4; // Sensor status, with test values
int rowStatus6 = 16; // Sensor status, with test values
int rowStatus7 = 0; // Sensor status, with test values
int rowStatus8 = 4; // Sensor status, with test values
void setup()
{
Serial.begin(9600); // Open serial comms to arduino Nano
SUART.begin(9600);
}
void loop() // run over and over
{
SUART.print(rowStatus1); SUART.print (',');//comma seperated data
SUART.print(rowStatus2); SUART.print (',');
SUART.print(rowStatus3); SUART.print (',');
SUART.print(rowStatus4); SUART.print (',');
SUART.print(rowStatus5); SUART.print (',');
SUART.print(rowStatus6); SUART.print (',');
SUART.print(rowStatus7); SUART.print (',');
SUART.print(rowStatus8); SUART.print (',');
SUART.print ('\n');
delay (5000); //test interval
}
3. Upload the following sketch in MEGA.
char myData[50];
char *temPtr;
void setup()
{
Serial.begin(9600);
Serial3.begin(9600);
}
void loop()
{
byte n = Serial3.available();
if (n != 0)
{
byte m = Serial3.readBytesUntil('\n', myData, 50);
myData[m] = '\0'; //null-byte
// Serial.println(myData);
//------------------------------
unsigned int s1 = strtoul(myData, &temPtr, 10);
unsigned int s2 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s3 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s4 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s5 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s6 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s7 = strtoul(temPtr + 1, &temPtr, 10);
unsigned int s8 = strtoul(temPtr + 1, &temPtr, 10);
//----------------------------------------------
Serial. println(s1, DEC); Serial. println(s2, DEC);
Serial. println(s3, DEC); Serial. println(s4, DEC);
Serial. println(s5, DEC); Serial. println(s6, DEC);
Serial. println(s7, DEC); Serial. println(s8, DEC);
Serial.println("=========================");
}
}
4. Check that the Serial Monitor of MEGA shows the received status values correctly.
4
=========================
0
4
16
0
4
16
0
4
=========================
0
4
16
0
4
5. Working Principle of strtoul() Function:
The function parses (reads a character from a character type array and checks if it is a decimal or hexadecimal digit) a string (array of characters) and stops at the non-digit character. The ASCII codes of the digits which have been parsed so far are converted into a numerical number and are saved in a variable. For example:
char myArray[] = “1234, 56, 78”;
char *temPtr;r
unsigned int x1 = strtoul(myArray, &temPtr, 10); // x1 = 0x04D2
Serial.println(x1, DEC); //shows: 1234
The arg3 (= 10) says that the function looks for decimal digits in the array. The parsing stops at the first comma (,); there remains the sub-array/sub-string (, 56, 78) which will be parsed next time to extract 56. Now, we need a pointer variable (*temPtr) to point the beginning of the sub-array. The arg2 (= &temPtr) passes to the pointer variable the address of the character at which parsing had stopped and thus offers a way to the strtoul() function to locate the beginning of the sub-array.