Take the Sensor Expansion Shield and stack it on top of your microcontroller – make sure that the pins are correctly aligned to avoid damage to the shield. See the diagram below for further details:
Take the Digital Push Button module and connect it to Digital Pin 2 (be sure that the power, ground and signal connections are correct or you risk damaging your components!)
Fig. 2-1 Digital Pin Connection
When the connections are made, connect the USB cable. This will power on the microcontroller. We can now prepare our program to upload.
Serial Port Monitoring
Open Arduino IDE and select: File > Examples > 01.Basics > DigitalReadSerialThe following code should appear:
int pushButton = 2; //connect to digital pin 2 void setup() { // initial function Serial.begin(9600); // set up baud rate of the serial port pinMode(pushButton, INPUT); // set the button to be in the output mode } void loop() { //main function int buttonState = digitalRead(pushButton); // record statistics about the status of digital pin 2 Serial.println(buttonState); // Serial port print statistics about the status of digital pin 2 delay(1); // delay 1ms }
Click “Upload”. Arduino IDE will verify the code and then upload it to your microcontroller.
Once the upload is complete, open the serial monitor. To do this, navigate to Tools > Serial Monitor, or click the magnifying glass icon on the top right hand corner of the toolbar.
The serial monitor shows information from the arduino microcontroller. We are going to use it to view the status of the button. You should see “0” appearing continuously. This indicates that the button is off (not being pressed).
If you press the button, you will see “1” appear for as long as the button is pressed. This indicates that the button is on (being pressed).
“0” and “1” or off and on are the two values of digital signal. We can use this in various ways with our devices.
Analog Signal
In this section we are going to explore analog signal in more detail. We are going to use a sensor which uses analog values: a rotation sensor.
Connect the rotation sensor to the DFRduino UNO (the same as Arduino UNO) Analog Pin 0. Make sure that signal, ground and power are connected to the correct corresponding pins, just like in the previous session. Connect the USB cable to the arduino microcontroller to power it on. We can now upload a program.
Fig. 2-2 Analog Pin Connection
Code Input
In Arduino IDE, navigate to File > Examples > 01.Basics > AnalogReadSerial A new window with a program will appear. It should read as follows: void setup() { //Initial setup Serial.begin(9600); //Set baud rate } void loop() { //Main function int sensorValue = analogRead(A0); // Read status of analog pin 0. Serial.println(sensorValue); // Print status of pin 0 in Serial Monitor delay(1);//Delay 1ms}
Click “Upload”. Arduino IDE will verify the code and then upload it to the microcontroller.
Once the upload is complete, open Arduino IDE’s serial port monitor. To do this, navigate to Tools > Serial Monitor Set baud rate of the serial port to be 9600 baud.
A series of values will flash in a column in the serial monitor.
Try to turn the rotational sensor. A figure between 0 and 1023 will show up, depending on how far the rotational sensor’s shaft is rotated. 0 means no rotation and 1023 means a full rotation.
The Difference Between Digital Pins And Analog Pins
Serial Port Monitor
We use the Serial Monitor to view information from the microcontroller. We can also use it to send information back to the microcontroller, and interact in with it in various ways while it runs a program.
Code Differences
If you examine the code in detail, you can see that digital pins and analog pins are read using different commands.
To read the value of a digital pin, we use the command: digitalRead() To read the value of an analog pin, we use the command: analogRead()
Digital Pins: int buttonState = digitalRead(pushButton); // read values from digital pin2
Analog Pins: int sensorValue = analogRead(A0); //read values from analog pin0
This will be explained in more detail in the next few sessions.
Try It Yourself
The sensors in your DFRobot Gravity: Arduino starter kit connect in much the same way as the ones demonstrated. Just make sure your power, ground and signal connections are correct. Once connected, you can check the serial monitor for output and see what values they output. Try to experiment and have fun!
This article takes a closer look at each of these devices, comparing them across key areas like Python support, ease of use, Python programming tools, pin design, and hardware projects.
Deciding between Scratch and Python for your child's coding journey? This article compares both languages based on learning background, goals, methods, and difficulty.