CmdSerial

Debug and control Arduino sketches from the Serial Monitor.

Set variables, watch live values, and list commands — without scattering Serial.print calls through your firmware.

Features

• Set sketch variables from Serial (temp 23.4)
• Show / stop live monitoring of values (sensors show)
• Built-in help listing for all registered commands
• Templated set() / print() — works with int, float, String, and other numeric types
• "..."_f PROGMEM labels (same idea as F("..."), less noise)
• println(...) to dump several fields on one line

Installation

Arduino Library Manager: search for CmdSerial, or install from ZIP / clone into your libraries folder:

git clone https://github.com/fire1/CmdSerial.git

Then restart the Arduino IDE.

Quick start

#include <CmdSerial.h>

CmdSerial cmd;
int testInt = 0;
float temperature = 21.5;

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

void loop() {
    cmd.listen();  // required every loop

    cmd.set("test"_f, testInt, "Set the test integer"_f);
    cmd.set("temp"_f, temperature, "Set temperature"_f);

    if (cmd.show("test"_f, "Monitor testInt"_f)) {
        cmd.print("Test value:"_f, testInt);
    }

    if (cmd.show("sensors"_f, "Print several values"_f)) {
        cmd.println("temp"_f, temperature, "test"_f, testInt);
    }
}

Open the Serial Monitor (newline ending). Try:

Command	Effect
help	List all commands
test help	Help for one command
test 12	Set testInt to 12
temp 23.4	Set temperature
test show	Start monitoring
test stop	Stop monitoring
sensors show	Print several fields each interval

Usage

Setup

#include <CmdSerial.h>
CmdSerial cmd;           // uses Serial by default
// CmdSerial cmd(Serial1);  // or any Stream

Call cmd.listen() once per loop().

Set a variable

float temperature;
if (cmd.set("temperature"_f, temperature, "Board temperature"_f)) {
    // optional: ran only when a new value was applied
}

Serial input: temperature 21.5

set() works with numeric types and String. Confirmation messaging can be disabled with a fourth argument: false.

Monitor values (show)

if (cmd.show("data"_f)) {                    // every 500 ms while active
    cmd.print("Output"_f, testInt);
}

if (cmd.show("banana"_f, "Help text"_f, 1000)) {  // custom interval
    cmd.print("Banana"_f, banana);
}

• name show — start printing on the interval
• name stop — stop

Print helpers

cmd.print("label"_f, value);                           // one line: label <sep> value
cmd.println("temp"_f, temperature, "hum"_f, humidity); // several fields on one line

PROGMEM strings (_f)

"Hello"_f keeps the text in flash on AVR, like F("Hello"):

cmd.print("Test value:"_f, testInt);
// same as:
cmd.print(F("Test value:"), testInt);

Help

Input	Result
help	Lists every set / show command registered in the sketch
<name> help	Help text for that command

Keywords

Default separator is space; end of line is \n.

Keyword	Role
show	Start monitoring
stop	Stop monitoring
help	List or describe commands

Override via macros before including the header (CmdSerial_KeywordShow, CmdSerial_ShowTime, …) — see src/CmdSerial.h.

Try it online

Wokwi playground — type help in the terminal.

Documentation

Full API: docs/api.md

License

MIT — see LICENSE.txt.