Hello! I am trying to receive three separate numbers from the serial port and then convert all of them into their own respective float variables so they can be mathematically manipulated separately. This is what I have so far: char input, lower, upper; //void setup() code void loop() { if ( Serial.available()) //Checks the availability of Serial port { input = Serial.read(); // Read the data and stores it in variable lower = Serial.read(); upper = Serial.read(); } float input; float lower; float upper; //Rest of the code follows } However, I fear that I just write over the variable each time, so that input, lower and upper are all just the last entered variable. Some direction and help would be much appreciated! Thank you!

Assume that your Arduino UNO is expecting to receive 125.75, 61.73, and 243.69 from a remote sender/ Serial Monitor as ASCII codes over Serial Port; after reception, the data items would be saved in these variables: float y1, float y2, and float y3. 1. Upload the following sketch in UNO. char myData[30] = {0}; void setup() { Serial.begin(115200); } void loop() { byte n = Serial.available(); if (n != 0) { byte m = Serial.readBytesUntil('\n', myData, 30); myData[m] = '\0'; //null-byte float y1 = atof(strtok(myData, ",")); Serial.print("float y1 = "); Serial.println(y1, 2); float y2 = atof(strtok(NULL, ",")); Serial.print("float y2 = "); Serial.println(y2, 2); float y3 = atof(strtok(NULL, ",")); Serial.print("float y3 = "); Serial.println(y1, 2); } } 2. Open Serial Monitor at Bd = 115200 with Newline option in the Line ending box. 3. Enter the following string in the InputBox of Serial Monitor and then click on the Send Button. 125.75, 61.73, 243.69 4. Check that the OutputBox of Serial Monitor shows: float y1 = 125.75 float y2 = 61.73 float y3 = 243.69

[image] rvandaveer: if ( Serial.available()) //Checks the availability of Serial port { input = Serial.read(); // Read the data and stores it in variable lower = Serial.read(); upper = Serial.read(); } You only know that there's at least one character available, yet you go right ahead and read three of them Time for a rethink.

The three variable would come from a user input entered into the serial port, and I am honestly unsure the format! This is my first time using the serial port for user inputs, so even though I have researched about this method, I still don't have a great grasp on all the fine details. (Before this I was using a physical keypad wired to the Arduino for user inputs!)

I actually didn't know that! Could you please elaborate on what you're saying and perhaps point me in a direction to go rethink?

The way you have used Serial.available, all you can tell is that there are zero characters available OR at least one character available. If there's only one character available (most likely scenario, after zero available) then it makes no sense to read three characters.

[image] rvandaveer: The three variable would come from a user input entered into the serial port, and I am honestly unsure the format! think you need to specify what the program is to do, i.e. what is the input data, what processing, what output etc, etc etc you cannot start to code until you have some idea what is program is to do possibly start by looking at some tutorials? get some idea what the various microcontroller development boards can do?

[image] rvandaveer: I am trying to receive three separate numbers from the serial port A good place to start would be to study the Serial Input Basics tutorial on this forum.

Your problem is that at the moment you don't understand clearly how computers store and transmit data. The digit '1' is not sent as a number. It is sent as numeric value that represents a character which is a one. You read characters one at a time then you need to work out what numbers those characters represent. Look up ASCII

[image] Railroader: Serial.parseFloat Serial.parseFloat() will parse characters read from Serial into a float.

Exactly! I use for an application ready for sharp work. Serial monitor sends a float to the controller some times. I thought the OP wanted to transfer floats.

so far there has been no mention of the microcontroller to be used it may be something with a little more power than a UNO e.g. an ESP32 using sscanf() // parse serial data input 125.75, 61.73,243.69 char myData[30] = { 0 }; void setup() { Serial.begin(115200); } void loop() { byte n = Serial.available(); if (n != 0) { byte m = Serial.readBytesUntil('\n', myData, 30); myData[m] = '\0'; //null-byte float y1, y2, y3; if (sscanf(myData, "%f,%f,%f", &y1, &y2, &y3) == 3) { Serial.println("parsed three floats ok"); Serial.print("float y1 = "); Serial.println(y1, 2); Serial.print("float y2 = "); Serial.println(y2, 2); Serial.print("float y3 = "); Serial.println(y3, 2); } else Serial.println("error in input!"); } } serial monitor when given "125.75, 61.73,243.69" displays parsed three floats ok float y1 = 125.75 float y2 = 61.73 float y3 = 243.69

How to receive multiple variables from the serial port and then convert them into a float?

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anon94801460 February 25, 2023, 9:58pm 10

A good place to start would be to study the Serial Input Basics tutorial on this forum.

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How to receive multiple variables from the serial port and then convert them into a float?

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