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\nUsing Serial.read() with Arduino | Part 2\n

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\n\nPublisher:\n\nProgramming Electronics Academy\n\n\n
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\nNow let’s tackle the first step of our algorithm – we create a character array to hold the incoming message and a position variable to help us move through each element in the array. We’ll also create a constant to hold the max length of...\nNow let’s tackle the first step of our algorithm – we create a character array to hold the incoming message and a position variable to help us move through each element in the array. We’ll also create a constant to hold the max length of our message and use this to initialize the character array.

const unsigned int MAX_MESSAGE_LENGTH = 12;

Now we need to check if any bytes are available in the serial receive buffer and while there are we need to read in the bytes in and save them to a temporary variable. We can use a while loop, Serial.available, Serial.read() to make this happen.

Now we need to check to see if the byte we read is a terminating character or not… We can use an if-else statement for that. If it’s not a terminating character we’ll do one thing, and if it is a terminating character we’ll do something else.

Now if we do get the terminating character that means we have received our entire message and we can actually do something with the message or data we received. In this case we’ll print the message to the Serial Monitor window. We’ll also need to reset our character array to prepare for the next message.

Before we can call this complete, we need to enforce the max message length in the protocol. This will prevent us from exceeding the space that we allotted in our character array. We can add this guard to our existing if statement.

if ( inByte != '\\n' && (message_pos - MAX_MESSAGE_LENGTH - 1) )
FULL SERIAL.READ() CODE

Here is the complete code to use Serial.read() to read in the entire message:

//Many thanks to Nick Gammon for the basis of this code
const unsigned int MAX_MESSAGE_LENGTH = 12;

void setup() {
Serial.begin(9600);
}

void loop() {

//Check to see if anything is available in the serial receive buffer
while (Serial.available() _ 0)
{
//Create a place to hold the incoming message
static char message[MAX_MESSAGE_LENGTH];
static unsigned int message_pos = 0;

//Read the next available byte in the serial receive buffer
char inByte = Serial.read();

//Message coming in (check not terminating character) and guard for over message size
if ( inByte != '\\n' && (message_pos - MAX_MESSAGE_LENGTH - 1) )
{
//Add the incoming byte to our message
message[message_pos] = inByte;
message_pos++;
}
//Full message received...
else
{
//Add null character to string
message[message_pos] = '\\0';

//Print the message (or do other things)
Serial.println(message);

//Reset for the next message
message_pos = 0;
}
}
}

OK. This feels like a ton – I know!\n
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Resource Details

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14:32
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Grade
Higher Ed
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Subjects
STEM
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Source:
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\nProgramming Electronics Academy\n\n
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Date
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2021
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Language
English
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For Teacher Use
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data, reading, electronics
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Additional Tags

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arduino, arduino(brand), arduino tutorial, arduino lesson, open source hardware group, learning arduino, microcontrollers, arduino ide, arduino sketch, c++, programming electronics academy, terminating character, serial port, serial communication, temporary variable, max length, character array, serial receive, position variable, full message, serial read, sending data, message position, serial, variable, array, sending, position, loop, function, read, program, devices, inside, code, hold, buffer, bytes, protocol
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