diff --git a/examples/serial_binboard/serial_binboard.ino b/examples/serial_binboard/serial_binboard.ino
index 591110c..4d7eeb6 100644
--- a/examples/serial_binboard/serial_binboard.ino
+++ b/examples/serial_binboard/serial_binboard.ino
@@ -14,12 +14,17 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>. */
 
 #include "LiBoard.h"
+#include <string.h>
 
+// !!! choose mode: 1 = global single value, 0 = per-square array !!!
+#define USE_GLOBAL_THRESHOLD 0
+
+#if USE_GLOBAL_THRESHOLD 
 // Option 1 - Global Threshold (Applies to all photoresistors)
-const unsigned short THRESHOLD = 100;
+unsigned short THRESHOLD = 100;
 
+#else
 // Option 2 - Per-square threshold (Applies to each individual photoresistor)
-/*
 unsigned short THRESHOLD[64] = {
   // A1..H1
   150, 150, 150, 150, 150, 150, 150, 150,
@@ -36,9 +41,11 @@ unsigned short THRESHOLD[64] = {
   // A7..H7
   300, 300, 300, 300, 300, 300, 300, 300,
   // A8..H8
-  300, 300, 300, 300, 300, 300, 300, 300
+  300, 300, 300, 300, 300, 300, 300, 300,
 };
-*/
+#endif
+
+bool calibrating = false;
 
 LiBoard board = LiBoard();
 unsigned long long lastBinBoard = 0;
@@ -49,12 +56,67 @@ void writeBinaryBoard(unsigned long long binBoard) {
     Serial.write((unsigned char)(binBoard>>(8*(7-i))));
 }
 
+// print a single CSV snapshot of raw ADC values (A1..H8 in LiBoard order)
+void printRawSnapshotCSV() {
+  board.getData();                   // fills board.values[0..63]
+  for (int i = 0; i < 64; ++i) {
+    Serial.print(board.values[i]);
+    if (i < 63) Serial.print(',');
+  }
+  Serial.println();
+}
+
 void setup() {
   delay(3000);
   Serial.begin(9600);
 }
 
 void loop() {
+  // Serial Monitor arguements
+  if (Serial.available()) {
+    int c = Serial.read();
+    // if host sends '?', reply with one CSV line of raw ADC values
+    if (c == '?') {
+      printRawSnapshotCSV();
+    }
+
+    // Calibration Mode for editing THRESHOLD
+    if (c == 'c') {
+      calibrating = true;
+      Serial.println("Calibration Mode Activated!");
+    }
+
+    while (calibrating) {
+      if (Serial.available()){
+        // read a whole line the user pasted
+        String line = Serial.readStringUntil('\n');
+        line.trim();
+        if (line.length() == 0) continue;
+
+#if USE_GLOBAL_THRESHOLD        
+        // Global Threshold Calibration
+        long newThreshold = line.toInt();
+        THRESHOLD = (unsigned short)newThreshold;
+#else
+        // Per-Square Calibration
+        char buf[1024];
+        line.toCharArray(buf, 1024);
+        char* tok = strtok(buf, ",");
+
+        int i = 0;
+        while (tok && i < 64) {
+          THRESHOLD[i++] = (unsigned short)atoi(tok);
+          tok = strtok(nullptr, ",");
+        }
+#endif
+        calibrating = false;
+        // eat non-numeric to avoid getting stuck
+        while (Serial.available()) Serial.read();
+      }
+    }
+  }
+
+  // Bitboard logic for normal use
   currentBinBoard = board.getBinaryBoard(THRESHOLD);
   if (currentBinBoard != lastBinBoard) {
     writeBinaryBoard(currentBinBoard);