added ping command for device identification

analog_system_monitor_arduino/analog_system_monitor_arduino.ino

@@ -1,6 +1,15 @@
 #include <Arduino.h>
 #include <RP2040_PWM.h>
 
+// -------------------------------
+// Firmware version
+// -------------------------------
+const char* FIRMWARE_VERSION = "V1.0";
+
+// -------------------------------
+// PWM setup
+// -------------------------------
+
 const uint8_t NUM_CHANNELS = 8;
 uint8_t pwmPins[NUM_CHANNELS] = {14, 15, 26, 27, 8, 7, 6, 5};
 
@@ -28,7 +37,6 @@ float calibratedPoints[NUM_CHANNELS][5] = {
 // -------------------------------
 
 float currentDuty[NUM_CHANNELS] = {0.0f};
-
 RP2040_PWM* pwm[NUM_CHANNELS];
 
 // -------------------------------
@@ -37,7 +45,6 @@ RP2040_PWM* pwm[NUM_CHANNELS];
 
 unsigned long lastSerialTime = 0;
 const unsigned long watchdogTimeout = 5000;  // 5 seconds
-const float fadeStep = 0.001f;                // 0.001% per ms
 unsigned long lastFadeTime = 0;
 
 // -------------------------------
@@ -87,6 +94,15 @@ void loop() {
   while (Serial.available()) {
     String s = Serial.readStringUntil('\n');
     s.trim();
+
+    // --- Device identification command ---
+    if (s.equalsIgnoreCase("PING")) {
+      Serial.print("Analog_System_Monitor_");
+      Serial.println(FIRMWARE_VERSION);
+      lastSerialTime = millis();
+      continue;
+    }
+
     int eq = s.indexOf('=');
     if (eq > 0) {
       int ch = s.substring(0, eq).toInt();
@@ -106,8 +122,7 @@ void loop() {
   // -------- Watchdog fade-to-zero (time-based exponential) --------
   if (millis() - lastSerialTime > watchdogTimeout) {
 
-    // Apply fade only every X ms
-    const unsigned long fadeInterval = 1;  // adjust for slower/faster decay
+    const unsigned long fadeInterval = 1;
 
     if (millis() - lastFadeTime >= fadeInterval) {
       lastFadeTime = millis();
@@ -116,7 +131,7 @@ void loop() {
 
         if (currentDuty[ch] > 0.0f) {
 
-          const float fadeFactor = 0.999f;   // exponential decay per interval
+          const float fadeFactor = 0.999f;
           currentDuty[ch] *= fadeFactor;
 
           if (currentDuty[ch] < 0.01f)