numpad kinda working

extensions/platformio/keypad_read/src/main.cpp

@@ -0,0 +1,48 @@
+#include <Arduino.h>
+
+const int BUZZER_PIN = 6;
+const int allPins[] = {0, 1, 2, 3, 4, 5, 7}; 
+const int numPins = 7;
+
+unsigned long lastDebounceTime = 0;
+const int debounceDelay = 250; 
+
+void setup() {
+  Serial.begin(115200);
+  for (int i = 0; i < numPins; i++) {
+    pinMode(allPins[i], INPUT_PULLUP);
+  }
+}
+
+void loop() {
+  // Only scan if we aren't in the middle of a "hit" lockout
+  if (millis() - lastDebounceTime < debounceDelay) return;
+
+  for (int s = 0; s < numPins; s++) {
+    int strobe = allPins[s];
+
+    pinMode(strobe, OUTPUT);
+    digitalWrite(strobe, LOW);
+    delayMicroseconds(100); // Slightly longer for stability
+
+    for (int i = 0; i < numPins; i++) {
+      int target = allPins[i];
+      if (target == strobe) continue;
+
+      if (digitalRead(target) == LOW) {
+        // WE FOUND ONE!
+        Serial.print("SINK:");
+        Serial.print(strobe);
+        Serial.print(" READ:");
+        Serial.println(target);
+
+        //tone(BUZZER_PIN, 2000, 50);
+        lastDebounceTime = millis();
+        
+        pinMode(strobe, INPUT_PULLUP);
+        return; // Jump out of the whole loop to reset the lockout
+      }
+    }
+    pinMode(strobe, INPUT_PULLUP);
+  }
+}