Adjust our Boolean flip-flop, to use pull-ups

Adjust our Boolean flip-flop, to use pull-ups to avoid spurious input
signals. We have to invert our logic as well.

flip_flop_with_3inputs_boolean_pull/flip_flop_with_3inputs_boolean_pull.ino

@@ -0,0 +1,34 @@
+/*
+  Adjust our Boolean flip-flop, to use pull-ups to avoid
+  spurious input signals. We have to invert our logic as well.
+ */
+
+int led = 13;           // set pin 13 LED variable name
+int newled = 5;         // add our second LED on pin 5
+int time_delay = 500;   // set time delay (mS) duration here
+
+void setup() {                
+  pinMode(led, OUTPUT);       // set up LED pin 13 as output
+  pinMode(newled, OUTPUT);    // set second LED pin 5 as output
+  pinMode(8, INPUT_PULLUP);   // set up pin 8 as an input + pullup
+  pinMode(7, INPUT_PULLUP);   // set up pin 7 as an input + pullup
+  pinMode(6, INPUT_PULLUP);   // set up pin 6 as an input + pullup
+}
+
+// the loop routine runs over and over again forever:
+void loop() {
+  // if any pin 6 or 7 or 8 is LOW
+  // notice the ! in front of each Read to "not" it
+  if (! digitalRead(6) || ! digitalRead(7) || ! digitalRead(8)) {
+    time_delay = 250;         // set delay to 250
+  }
+  else {
+    time_delay = 1000;        // set (default delay)
+  }
+  digitalWrite(led, HIGH);    // turn LED ON (HIGH is the voltage level)
+  digitalWrite(newled, LOW);  // turn newLED OFF (LOW is the voltage level)
+  delay(time_delay);          // wait for time_delay
+  digitalWrite(led, LOW);     // turn LED OFF by making the voltage LOW
+  digitalWrite(newled, HIGH); // turn LED ON by making the voltage HIGH
+  delay(time_delay);          // wait for time_delay
+}