Arduino

1 PTM Control

Build It

We are going to now learn how to include digital control to your Arduino.
To do this, we will need to connect a PTM switch to your breadboard.
Look at the photo below to see how to wire the board.
You will need the following.
1. 1 X PTM switch
2. 1 X 10K resistor
3. 2 X Red single core jump wire
4. 1 X Black single core jump wire
Before we can start wiring up the switch, we need to know how the switch is connected.
The switch is wired in 2 rows, when the button is pushed, all 4 pins are connected.

The PTM switch needs to be connected across the gap in the centre of the breadboard.
It will only fit one way around as the pins are connected in a rectangle shape.
We are going use the input A5 for the switch. This will need a 10k pull down resistor and connection to power.
Please note there is a black jump wire at the end of the board to connect ground to the bottom of the breadboard.

Below is the circuit diagram of how you would connect it is it was a Genie microcontroller.

Code It

We now need to start coding the switch to control the LED.
Open up your previous code for the LED.
First, we need to declare the following variables.
1. int buttonPin = A5; // This declare which pin the button is connected to.\
2. int buttonState = 0; // Set the state of the button to low/0

Next we need to setup the button as an input.
1. pinMode(buttonPin, INPUT); //This declares the button as an input on A5

Now we need to add the instructions for the loop.
First we need to tell the microcontroller that the input it is going to read is a digital input.
1. buttonState = digitalRead(buttonPin);
Next we need to instruct the micrcontroller to look at the state of the input. It will then decide using an if/else statement whether to turn on the output or turn off the output.
1. if (buttonState == HIGH)
2. digitalWrite(ledPin, HIGH); // Turn on the LED
3. else
4. digitalWrite(ledPin, LOW); // Turn off LED
Here is some help with the if and else statements (you can jump to 1 minute 50 seconds for the instructions)

Now click the upload button with the Arduino connected.

Below is a video of how it should work.

Below is a video explaining how to use the digitalRead and digitalWrite instructions (it does not use the Arduino Nano)

Badge It

To complete the badges you will need to Take a photo of your finished program and finished breadboard.
Silver: Upload a screenshot of your switch control sketch and a photo of your finished breadboard.
Gold: Write a sketch to allow the LED to flash continuously when the switch is pressed and then stop when the switch is released.

Platinum: Write a code to make the switch turn the LED on permanently and then off permanently each time you press the switch. Stuck? Try here for some ideas on how to make a latching switch Latching Switch. Alternatively, one approach - while not perfect - could be like this...

At the top of the sketch (not in the main loop)...
Make a variable called 'ledState' and set it to zero.


In the main loop...

IF the switch is pushed THEN
    IF ledState is 0 THEN
        turn the LED on
        wait about a second
        set ledState to 1
    ELSE
        turn the LED off
        wait about a second
        set ledState to 0