Subtask 3 will add to the same circuit you assembled for Subtasks 1 and 2 by introducing the single pushbutton component to the mini breadboard, as seen in Figure 5-1. Subtask 3 will require the following additional components beyond what you’ve already assembled. All of these are available in the Mintronics: Survival Pack:

Figure 5-1. A single pushbutton that will light the LED when pressed

Add the pushbutton to the mini breadboard by inserting it so that the distance between the two top legs is a single hole (on a single row) and the distance between a top and a bottom leg has two holes between it (spanning four rows altogether). A close-up of this can be seen in Figure 5-2.

Figure 5-2. The pushbutton is inserted into the mini breadboard in a specific way

Figure 5-3 shows the pushbutton inserted into the mini breadboard. Make certain to leave the leftmost hole open on the top and bottom row where the pushbutton is inserted. (These will be used to add jumper wires.)

Figure 5-3. Leave an empty hole to the left of the top row and bottom row of the pushbutton

Connect two jumper wires to the pushbutton, as shown in Figure 5-4. One jumper wire is inserted in the first hole at the top row of the pushbutton and the second jumper wire is inserted in the empty bottom row of the mini breadboard.

Next, add a single 100 ohm resistor (this resistor will be referred to as RES2) to the mini breadboard, as shown in Figure 5-5. This resistor (RES2) will have one of its leads inserted into the row where the first resistor (RES1) is inserted, and the jumper wire goes to GND. The other lead for RES2 can be inserted in a row just above the pushbutton.

Figure 5-4. Jumper wires will be needed to connect the pushbutton to the MintDuino

Figure 5-5. Add a second resistor (RES2) to serve as a pulldown resistor for the pushbutton

As shown in Figure 5-6, insert the top jumper wire of the pushbutton into the row containing only a RES2 lead (not the row that shares GND with RES1) and insert the bottom jumper wire of the pushbutton into the bottom (empty) row of the mini breadboard (which will serve as a +5V supply for the mini breadboard).

Figure 5-6. Wire up the pushbutton to GND and to +5V

Finally, add two more jumper wires. Insert the red one into the bottom row of the mini breadboard and connect it to +5V on the MintDuino—we’ll call this the JUMPV. Insert the other jumper wire where the pushbutton’s top jumper wire and RES2 are inserted. Then connect this new jumper wire to Digital Pin 4 (or Pin 6 on the ATmega chip)—we’ll call this JUMP4. This corresponds to Row 14 on the MintDuino (only if you’ve taken care to wire it up exactly as the online instructions specify). You can plug that jumper wire into any free hole between a and e on Row 14. Both of these new jumper wires can be seen in Figure 5-7.

Figure 5-7. Connect the circuit to the MintDuino

// MintDuino NoteBook 1 – Subtask 3

int ledPin = 7; // Digital Pin 7 for LED anode connection
int button = 4; // Use pin 4 for the button

void setup() {
    pinMode(ledPin, OUTPUT);
    digitalWrite(ledPin, LOW);
}

void loop() {
   int state = digitalRead(button);
   if (state == HIGH) { // determine if button is pressed or not
     lightLED();        // if it is, light the LED
   }
}

void lightLED(){ // only called when the button state is HIGH (pressed)
  digitalWrite(ledPin, HIGH);
  delay(1000);
  digitalWrite(ledPin, LOW);
}