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

[the_perfect_clock.git] / the_perfect_clock.ino

diff --git a/the_perfect_clock.ino b/the_perfect_clock.ino
index 318d641e1cbcaf392fa3527a34085d6862b81cbb..25294922e37eb4ea9aae6ba721ffdb062b21e995 100644 (file)
--- a/the_perfect_clock.ino
+++ b/the_perfect_clock.ino
@@ -87,6 +87,11 @@ 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() {
+
+  // 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();
        if (m != previous_millis) {
                millisecond += (m - previous_millis);
@@ -101,14 +106,13 @@ void loop() {
                                }
                        }
                }
-       }
+  }
        previous_millis = m;
 
        int pulse_length;
-       int signal = digitalRead(wwvb);                         // is the input high or low right now?
 
   if (signal) {
-    analogWrite(timecodeled, 10);       // it's too bright on my board so we dim it; change to digitalWrite() if not needed
+    analogWrite(timecodeled, 5);       // it's too bright on my board so we dim it; change to digitalWrite() if not needed
   }
   else {
     digitalWrite(timecodeled, LOW);
@@ -120,13 +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 {