Reduced hysteresis to 3 samples. Expanded valid pulse width range.

diff --git a/the_perfect_clock.ino b/the_perfect_clock.ino
index d437e392bfbd2ec2182770119718611d84251a2f..25294922e37eb4ea9aae6ba721ffdb062b21e995 100644 (file)
--- a/the_perfect_clock.ino
+++ b/the_perfect_clock.ino
@@ -87,27 +87,9 @@ void setup() {
 // Note: only write to the display when the readout needs to be updated.
 // Speaking I2C on every loop iteration jams the WWVB receiver.
 void loop() {
-  int signal;
-  static int total_samples = 0;
-  static int high_samples = 0;
-
-  // read from the WWVB receiver, with some hysteresis
-  if (total_samples >= 100) {
-    if (high_samples > 20) {
-      signal = HIGH;
-    }
-    else {
-      signal = LOW;
-    }
-    total_samples = 0;
-    high_samples = 0;
-  }
-  else {
-    total_samples += 1;
-    if (digitalRead(wwvb) == HIGH) {
-      ++high_samples;
-    }
-  }
+
+  // Reading it three times and taking the average gives us some hysteresis
+  int signal = (digitalRead(wwvb) + digitalRead(wwvb) + digitalRead(wwvb)) / 3;
 
   // has the timer ticked?
        unsigned long m = millis();
@@ -142,13 +124,13 @@ void loop() {
        else if ((!signal) && (previous_signal)) {              // trailing edge of pulse detected
                pulse_length = millis() - start_of_pulse;
 
-               if (pulse_length > 175 && pulse_length < 225) { // "0" bit ~= 200 ms (represented as "0")
+               if (pulse_length > 150 && pulse_length < 250) { // "0" bit ~= 200 ms (represented as "0")
                        this_pulse = 0;
                }
-               else if (pulse_length > 475 && pulse_length < 525) {    // "1" bit ~= 500 ms (represented as "1")
+               else if (pulse_length > 450 && pulse_length < 550) {    // "1" bit ~= 500 ms (represented as "1")
                        this_pulse = 1;
                }
-               else if (pulse_length > 775 && pulse_length < 825) {    // marker bit ~= 800 ms (represented as "2")
+               else if (pulse_length > 750 && pulse_length < 850) {    // marker bit ~= 800 ms (represented as "2")
                        this_pulse = 2;
                }
                else {