# Setting map ranges suitably
**URL:** https://discourse.processing.org/t/setting-map-ranges-suitably/19130
**Category:** Electronics (Arduino, etc.)
**Created:** [March 29, 2020, 5:58am UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130 "2020-03-29T05:58:41Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@tefa](https://discourse.processing.org/u/tefa)
#### Post date: [March 29, 2020, 5:58am UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/1 "2020-03-29T05:58:41Z")
Hello everyone! can some one please explain to me why my map parameters of both Arduino and processing codes are not fluidly animating the array of pngs I have declared and then stopping with an ArrayIndexOutBoundsException error, thank you
**Arduino**
```auto
const int pingPin = 9;
void setup() {
Serial.begin(9600);
}
void loop() {
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
duration = pulseIn(pingPin, HIGH);
cm = microsecondsToCentimeters(duration);
int val = map(cm, 0, 32, 0, 600);
Serial.println(cm);
delay(100);
}
long microsecondsToCentimeters(long microseconds) {
return microseconds / 29 / 2;
}
```
**Processing**
```auto
import processing.serial.*;
Serial myPort;
String val;
PImage[] Artboard= new PImage[32];
int counter = 0;
PImage img;
int frame ;
float yPos;
int cm;
int intVal;
void setup () {
size(767, 600);
String portName = Serial.list()[2];
myPort = new Serial(this, portName, 9600);
myPort.bufferUntil ( '\n' );
frameRate(60);
Artboard[0]=loadImage("Artboard_1.png");
Artboard[1]=loadImage("Artboard_2.png");
Artboard[2]=loadImage("Artboard_3.png");
Artboard[3]=loadImage("Artboard_4.png");
Artboard[4]=loadImage("Artboard_5.png");
Artboard[5]=loadImage("Artboard_6.png");
Artboard[6]=loadImage("Artboard_7.png");
Artboard[6]=loadImage("Artboard_8.png");
Artboard[7]=loadImage("Artboard_9.png");
Artboard[8]=loadImage("Artboard_10.png");
Artboard[9]=loadImage("Artboard_11.png");
Artboard[10]=loadImage("Artboard_12.png");
Artboard[11]=loadImage("Artboard_13.png");
Artboard[12]=loadImage("Artboard_14.png");
Artboard[13]=loadImage("Artboard_15.png");
Artboard[14]=loadImage("Artboard_16.png");
Artboard[15]=loadImage("Artboard_17.png");
Artboard[16]=loadImage("Artboard_18.png");
Artboard[17]=loadImage("Artboard_19.png");
Artboard[18]=loadImage("Artboard_20.png");
Artboard[19]=loadImage("Artboard_21.png");
Artboard[20]=loadImage("Artboard_22.png");
Artboard[21]=loadImage("Artboard_23.png");
Artboard[22]=loadImage("Artboard_24.png");
Artboard[23]=loadImage("Artboard_25.png");
Artboard[24]=loadImage("Artboard_26.png");
Artboard[25]=loadImage("Artboard_28.png");
Artboard[26]=loadImage("Artboard_29.png");
Artboard[27]=loadImage("Artboard_30.png");
Artboard[28]=loadImage("Artboard_31.png");
Artboard[29]=loadImage("Artboard_32.png");
Artboard[30]=loadImage("Artboard_33.png");
Artboard[31]=loadImage("Artboard_34.png");
}
void serialEvent (Serial myPort) {
yPos = float (myPort.readStringUntil ( '\n' ) ) ;
}
void draw() {
background(255, 255, 255);
frame = (int) map( yPos, 0, 32, 0, height );
println(frame, yPos);
image(Artboard[frame], 0, 0);
}
```
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 29, 2020, 2:36pm UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/2 "2020-03-29T14:36:55Z")
> [@tefa](#):
>
> frame = (int) map( yPos, 0, 32, 0, height );
you are using **frame** as an index for `Artboard`
Hence
`frame = (int) map( yPos, 0, 32, 0, Artboard.length-1 );`
When yPos is bigger than 32, `frame` could get bigger than Artboard.length-1, maybe. I think. That could be bad.
Then add
```auto
if (frame > Artboard.length-1)
frame = Artboard.length-1 ;
```
after the line with map()
Chrisir
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 29, 2020, 2:43pm UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/3 "2020-03-29T14:43:13Z")
> [@tefa](#):
>
> yPos = float (myPort.readStringUntil ( ‘\n’ ) ) ;
When my previous post doesn’t solve the issue, I would look at this line.
You could add
```auto
myString = myPort.readStringUntil(lf);
if (myString != null) {
yPos = float ( myString ) ; // does this work?
}
```
see [readStringUntil() / Libraries / Processing.org](https://www.processing.org/reference/libraries/serial/Serial_readStringUntil_.html)
---
### Author:  [@tefa](https://discourse.processing.org/u/tefa)
#### Post date: [March 29, 2020, 5:49pm UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/4 "2020-03-29T17:49:54Z")
This works perfectly
```auto
frame = (int) map( yPos, 0, 32, 0, ameba.length-1);
if (frame > ameba.length-1)
frame = ameba.length-1;
```
but if I flip this order
```auto
frame = (int) map( yPos, 32, 0, 0, ameba.length-1);
```
because I want the farthest reading of the ultrasonic mapping from first png to last, causes the out bound exception to appear. Adding
```auto
myString = myPort.readStringUntil(lf);
if (myString != null) {
yPos = float ( myString ) ; // does this work?
}
```
does not work.
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 29, 2020, 8:04pm UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/5 "2020-03-29T20:04:22Z")
> [@tefa](#):
>
> frame = (int) map( yPos, 32, 0, 0, ameba.length-1);
The order does matter
```auto
frame = (int) map ( yPos, 32, 0, ameba.length-1, 0);
if (frame > ameba.length-1)
frame = ameba.length-1;
```
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 29, 2020, 8:11pm UTC](https://discourse.processing.org/t/setting-map-ranges-suitably/19130/6 "2020-03-29T20:11:23Z")
> [@Chrisir](#):
>
> frame = (int) map ( yPos, 32, 0, ameba.length-1, 0);
ah, that would give you the same old result… bad.
what about
```auto
frame = (int) map ( yPos, // value
32, 0, // range 1
0, ameba.length-1); // range 2
println(frame); // now this is to debug! If you get a bound exception, check, what value frame had!
// check upper and lower bound
if (frame > ameba.length-1)
frame = ameba.length-1;
if (frame < 0)
frame = 0;
```