+#define AJAR_LOW_PASS_TAU 200
+byte ajar_low_pass_counter = 0;
+byte ajar_low_pass_last_value = ajar_last_state;
+byte get_ajar_status()
+{
+ b = ( (digitalRead(AJAR_PIN) == LOW)? SHUT : AJAR );
+ ajar_low_pass_counter = ( (b == ajar_low_pass_last_value)? ajar_low_pass_counter + 1 : 0 );
+ ajar_low_pass_last_value = b;
+ if (ajar_low_pass_counter >= AJAR_LOW_PASS_TAU)
+ {
+ ajar_low_pass_counter = 0;
+ return b;
+ }
+ else
+ return ajar_last_state;
+}
+
+void init_ajar()
+{
+ pinMode(AJAR_PIN, INPUT); // set pin to input
+ digitalWrite(AJAR_PIN, HIGH); // turn on pullup resistors
+ ajar_last_state = get_ajar_status();
+}
+
+//**********//
+