# Serial connection of Processing and Arduino
**URL:** https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344
**Category:** Electronics (Arduino, etc.)
**Tags:** homework
**Created:** [June 6, 2022, 3:13am UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344 "2022-06-06T03:13:53Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jinalilili](https://discourse.processing.org/u/jinalilili)
#### Post date: [June 6, 2022, 3:13am UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344/1 "2022-06-06T03:13:53Z")
I’m try to make a serial connection from processing to arduino. The idea is that when I press “a”, the speaker from Arduino will produce a sound and the same goes with another key pressed but with a different note. However, I’m a bit stuck with the codes. Can anyone let me know what is the problem of my codes?
Processing code:
```auto
import processing.serial.*;
Serial myPort;
int val; // Data received from the serial port
void setup()
{
size(200, 200);
String portName = Serial.list()[0];
myPort = new Serial(this, portName, 9600);
}
void draw() {
}
void keyPressed(){
if (key == 'a'){
myPort.write(1);
}
if (key == 'd'){
myPort.write(2);
}
}
void keyReleased(){
myPort.write(0);
}
```
Arduino code:
```auto
char val; // Data received from the serial port
int speakerPin = 8;
void setup() {
pinMode(speakerPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
while (Serial.available()) {
val = Serial.read();
}
if (val == '1') {
tone(speakerPin, 262, 200);
} else if (val == '2'){
tone(speakerPin, 523, 200);
}
delay(100);
}
```
Many many thanks!
---
### Author:  [@jafal](https://discourse.processing.org/u/jafal)
#### Post date: [June 6, 2022, 4:34am UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344/2 "2022-06-06T04:34:40Z")
Hi
Try this in Arduino side
```auto
if(Serial.available() > 0) {
```
---
### Author:  [@jafal](https://discourse.processing.org/u/jafal)
#### Post date: [June 6, 2022, 4:54am UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344/3 "2022-06-06T04:54:33Z")
Or try this code
```auto
byte x = 0;
int speakerPin = 8;
void setup()
{
pinMode(speakerPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
if (int(x) == 1) {
Do something
}
else if (int(x) == 2) {
Do something
}
}
void serialEvent() {
while (Serial.available()) {
x = Serial.read();
}
}
```
---
### Author:  [@glv](https://discourse.processing.org/u/glv)
#### Post date: [June 6, 2022, 10:59am UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344/4 "2022-06-06T10:59:15Z")
Hello @jinalilili,
A `'1'` (character) and `1` (integer number) are two different things.
Processing:
`myPort.write(1);`
Arduino:
`if (val == '1') // This will NEVER be equal to 1`
Reference:
[https://processing.org/reference/char.html](https://processing.org/reference/char.html)
This is a common error for those new to programming and serial communications.
Keep at it!
```auto
char a = '1';
// This will NOT be equal:
int b = 1;
//These will be equal:
//int b = 49; // ASCII for '1' in decimal
//int b = 0x31; // ASCII for '1' in hexadecimal
if (a == b)
println("Equal");
else
println("NOT Equal");
```
`:)`
---
### Author:  [@svan](https://discourse.processing.org/u/svan)
#### Post date: [June 6, 2022, 5:06pm UTC](https://discourse.processing.org/t/serial-connection-of-processing-and-arduino/37344/5 "2022-06-06T17:06:25Z")
Was also discussed here: [https://stackoverflow.com/questions/72494671/serial-connection-of-processing-and-arduino](https://stackoverflow.com/questions/72494671/serial-connection-of-processing-and-arduino). Not sure why this answer was not accepted. It would help if there was some feedback.