The best tools to make your project dreams come true



By Adafruit Industries

Adafruit IO Basics: Digital Input

Courtesy of Adafruit Industries

Overview

This guide is part of a series of guides that cover the basics of using Adafruit IO. It will show you how to send momentary button press data to Adafruit IO.

If you haven't worked your way through the Adafruit IO feed and dashboard basics guides, you should do that before continuing with this guide so you have a basic understanding of Adafruit IO.

You should go through the setup guides associated with your selected set of hardware, and make sure you have internet connectivity with the device before continuing. The following links will take you to the guides for your selected platform.

If you have went through all of the prerequisites for your selected hardware, you are now ready to move on to the Adafruit IO setup steps that are common between all of the hardware choices for this project. Let's get started!

Adafruit IO Setup

The first thing you will need to do is to login to Adafruit IO and visit the Settings page.

Click the VIEW AIO KEY button to retrieve your key.

Click the VIEW AIO KEY button to retrieve your key

A window will pop up with your Adafruit IO. Keep a copy of this in a safe place. We'll need it later.

Your AIO Key

Creating the Digital Feed

Next, you will need to create a feed called Digital. If you need help getting started with creating feeds on Adafruit IO, check out the Adafruit IO Feed Basics guide.

Creating the Digital Feed

Adding the Gauge Block

Next, add a new Gauge block to a new or existing dashboard. Name the block whatever you would like, and give it a max value of 1 and a min value of 0. Make sure you have selected the Digital feed as the data source for the gauge.

If you need help getting started with Dashboards on Adafruit IO, check out the Adafruit IO Dashboard Basics guide.

Block Settings

When you are finished editing the form, click Create Block to add the new block to the dashboard.

Click Create Block to add new block to the dashboard

Next, we will look at wiring the circuit.

Wiring

You will need the following parts for this tutorial:

      • 1x Adafruit IO compatible Feather
      • 3x jumper wires
      • 1x 10k resistor
      • 1x momentary button

You will need to connect the following pins to the button and 10k resistor:

      • Feather GND to one side of the momentary button
      • Feather Pin 5 to the other side of the momentary button
      • Feather 3V to one leg of a 10k resistor
      • The second leg of the 10k resistor to the same side of the momentary button as Pin 5

Note: Resistors are not polarized, so the 10k resistor can be connected to the circuit in either direction.

Wiring Diagram

Next, let's look at the example sketch we will be using.

Arduino Setup

You should go through the setup guides associated with your selected set of hardware, and make sure you have internet connectivity with the device before continuing. The following links will take you to the guides for your selected platform.

You will need to make sure you have at least version 2.3.1 of the Adafruit IO Arduino library installed before continuing.

Make Sure you have at least Version 2.3.1

For this example, you will need to open the adafruitio_06_digital_in example in the Adafruit IO Arduino library.

Open the adafruitio_06_digital_in

Next, we will look at the network configuration options in the sketch.

Network Config

To configure the network settings, click on the config.h tab in the sketch. You will need to set your Adafruit IO username in the IO_USERNAME define, and your Adafruit IO key in the IO_KEY define.

Set Your Username and Key

WiFi Config

WiFi is enabled by default in config.h so if you are using one of the supported WiFi boards, you will only need to modify the WIFI_SSID and WIFI_PASS options in the config.h tab.

Set WiFi SSID and Password

FONA Config

If you wish to use the FONA 32u4 Feather to connect to Adafruit IO, you will need to first comment out the WiFi support in config.h

Comment Out Default WiFi Config Lines

Next, remove the comments from both of the FONA config lines in the FONA section of config.h to enable FONA support.

Uncomment Both FONA Config Lines

Ethernet Config

If you wish to use the Ethernet Wing to connect to Adafruit IO, you will need to first comment out the WiFi support in config.h

Comment Out Default WiFi Config Lines

Next, remove the comments from both of the Ethernet config lines in the Ethernet section of config.h to enable Ethernet Wing support.

Uncomment Both Ethernet Config Lines

Next, we will look at how the example sketch works.

Code

The adafruitio_06_digital_in example uses digital pin 5 by default on all boards, and that can be modified if needed by changing the BUTTON_PIN define.

Note: If you are using the WICED Feather, you will need to change the BUTTON_PIN define to PC5 instead of the default setting of 5.

Copy Code
/************************ Example Starts Here *******************************/

// digital pin 5
#define BUTTON_PIN 5

The next chunk of code sets up two boolean variables to track button state, and an Adafruit IO Feed instance for a feed called digital.

Copy Code
// button state
bool current = false;
bool last = false;

// set up the 'digital' feed
AdafruitIO_Feed *digital = io.feed("digital");

In the setup function, we set the BUTTON_PIN as a digital input, and connect to Adafruit IO. The code will wait until you have a valid connection to Adafruit IO before continuing with the sketch. If you have any issues connecting, check config.h for any typos in your username or key.

Copy Code
void setup() {

// set button pin as an input
pinMode(BUTTON_PIN, INPUT);

// start the serial connection
Serial.begin(115200);

// wait for serial monitor to open
while(! Serial);

// connect to io.adafruit.com
Serial.print("Connecting to Adafruit IO");
io.connect();

// wait for a connection
while(io.status() < AIO_CONNECTED) {
Serial.print(".");
delay(500);
}

// we are connected
Serial.println();
Serial.println(io.statusText());

}

Next, we have the main  loop()  function. The first line of the loop function calls  io.run();  this line will need to be present at the top of your loop in every sketch. It helps keep your device connected to Adafruit IO, and processes any incoming data.

Copy Code
void loop() {

// io.run(); is required for all sketches.
// it should always be present at the top of your loop
// function. it keeps the client connected to
// io.adafruit.com, and processes any incoming data.
io.run();

The next chunk of code inside the loop() checks the current state of the button, and saves the state of the button in the current variable. Because we are using a pullup resistor, we will need to flip the button state.

If the button state is LOW it means the button is pressed, so we set  current = true;  . If the button state is HIGH it means the button is released, so we set  current = false; .

We then check if the current button state is equal to the last button state. If it is equal, we will return early and not continue with the rest of the loop.

Copy Code
  // grab the current state of the button.
// we have to flip the logic because we are
// using a pullup resistor.
if(digitalRead(BUTTON_PIN) == LOW)
current = true;
else
current = false;

// return if the value hasn't changed
if(current == last)
return;

The final chunk of the  loop()   function prints the current value to the Arduino Serial Monitor, and sends the current value to the digital feed on Adafruit IO. We also set  last = current;   so we can tell if the state of the button has changed in the next run of the loop.

Copy Code
  // save the current state to the 'digital' feed on adafruit io
Serial.print("sending button -> ");
Serial.println(current);
digital->save(current);

// store last button state
last = current;

}

Upload the sketch to your board, and open the Arduino Serial Monitor. Your board should now connect to Adafruit IO.

Copy Code
Connecting to Adafruit IO....

Adafruit IO connected.

You can now press the button, and you should see button presses being sent to Adafruit IO.

Copy Code
sending button -> 1
sending button -> 0
sending button -> 1
sending button -> 0

Check your dashboard on Adafruit IO, and you should see the gauge respond to button presses.

Adafruit IO Basics: Digital Input

Key Parts and Components

Add all Digi-Key Parts to Cart
  • 1528-1550-ND
  • 1528-1838-ND