# Processing - ControlP5 error . pls help!

**URL:** https://discourse.processing.org/t/processing-controlp5-error-pls-help/34514
**Category:** Coding Questions
**Created:** [January 7, 2022, 10:02pm UTC](https://discourse.processing.org/t/processing-controlp5-error-pls-help/34514 "2022-01-07T22:02:10Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![R4R31](https://avatars.discourse-cdn.com/v4/letter/r/a5b964/32.png) [@R4R31](https://discourse.processing.org/u/R4R31)
#### Post date: [January 7, 2022, 10:02pm UTC](https://discourse.processing.org/t/processing-controlp5-error-pls-help/34514/1 "2022-01-07T22:02:10Z")

</div>

I don’t know why I get this error. The guy who wrote it has no problem with it. can u help me?  
The ERROR appears when you press the “Move to position” button  
THIS IS THE ERROR:  
Jan 07, 2022 10:47:12 PM controlP5.ControlBroadcaster printMethodError  
SEVERE: An error occured while forwarding a Controller event, please check your code at move  
java.lang.reflect.InvocationTargetException  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)  
at java.base/java.lang.reflect.Method.invoke(Method.java:566)  
at controlP5.ControlBroadcaster.invokeMethod(Unknown Source)  
at controlP5.ControlBroadcaster.callTarget(Unknown Source)  
at controlP5.ControlBroadcaster.broadcast(Unknown Source)  
at controlP5.Controller.broadcast(Unknown Source)  
at controlP5.Button.setValue(Unknown Source)  
at controlP5.Button.activate(Unknown Source)  
at controlP5.Button.mouseReleased(Unknown Source)  
at controlP5.Controller.setMousePressed(Unknown Source)  
at controlP5.ControllerGroup.setMousePressed(Unknown Source)  
at controlP5.ControlWindow.mouseReleasedEvent(Unknown Source)  
at controlP5.ControlWindow.mouseEvent(Unknown Source)  
at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)  
at java.base/java.lang.reflect.Method.invoke(Method.java:566)  
at processing.core.PApplet$RegisteredMethods.handle(PApplet.java:1387)  
at processing.core.PApplet.handleMethods(PApplet.java:1541)  
at processing.core.PApplet.handleMouseEvent(PApplet.java:2484)  
at processing.core.PApplet.dequeueEvents(PApplet.java:2374)  
at processing.core.PApplet.handleDraw(PApplet.java:2212)  
at processing.awt.PSurfaceAWT$10.callDraw(PSurfaceAWT.java:1422)  
at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:354)  
Caused by: java.lang.NullPointerException  
at GUI\_for\_SCARA\_Robot.move(GUI\_for\_SCARA\_Robot.java:543)  
… 25 more

THIS IS THE CODE:

import processing.serial._;  
import controlP5._;  
import static processing.core.PApplet.\*;

Serial myPort;  
ControlP5 cp5; // controlP5 object

int j1Slider = 0;  
int j2Slider = 0;  
int j3Slider = 0;  
int zSlider = 100;  
int j1JogValue = 0;  
int j2JogValue = 0;  
int j3JogValue = 0;  
int zJogValue = 0;  
int speedSlider = 500;  
int accelerationSlider = 500;  
int gripperValue = 180;  
int gripperAdd=180;  
int positionsCounter = 0;

int saveStatus = 0;  
int runStatus = 0;

int slider1Previous = 0;  
int slider2Previous = 0;  
int slider3Previous = 0;  
int sliderzPrevious = 100;  
int speedSliderPrevious = 500;  
int accelerationSliderPrevious = 500;  
int gripperValuePrevious = 100;

boolean activeIK = false;

int xP=365;  
int yP=0;  
int zP=100;  
float L1 = 228; // L1 = 228mm  
float L2 = 136.5; // L2 = 136.5mm  
float theta1, theta2, phi, z;

String[] positions = new String[100];

String data;

void setup() {

size(960, 800);  
//myPort = new Serial(this, “COM3”, 115200);

cp5 = new ControlP5(this);

PFont pfont = createFont(“Arial”, 25, true); // use true/false for smooth/no-smooth  
ControlFont font = new ControlFont(pfont, 22);  
ControlFont font2 = new ControlFont(pfont, 25);

//J1 controls  
cp5.addSlider(“j1Slider”)  
.setPosition(110, 190)  
.setSize(270, 30)  
.setRange(-90, 266) // Slider range, corresponds to Joint 1 or theta1 angle that the robot can move to  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
cp5.addButton(“j1JogMinus”)  
.setPosition(110, 238)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG-”)  
;  
cp5.addButton(“j1JogPlus”)  
.setPosition(290, 238)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG+”)  
;  
cp5.addNumberbox(“j1JogValue”)  
.setPosition(220, 243)  
.setSize(50, 30)  
.setRange(0, 20)  
.setFont(font)  
.setMultiplier(0.1)  
.setValue(1)  
.setDirection(Controller.HORIZONTAL) // change the control direction to left/right  
.setCaptionLabel("")  
;

//J2 controls  
cp5.addSlider(“j2Slider”)  
.setPosition(110, 315)  
.setSize(270, 30)  
.setRange(-150, 150)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
cp5.addButton(“j2JogMinus”)  
.setPosition(110, 363)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG-”)  
;  
cp5.addButton(“j2JogPlus”)  
.setPosition(290, 363)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG+”)  
;  
cp5.addNumberbox(“j2JogValue”)  
.setPosition(220, 368)  
.setSize(50, 30)  
.setRange(0, 20)  
.setFont(font)  
.setMultiplier(0.1)  
.setValue(1)  
.setDirection(Controller.HORIZONTAL) // change the control direction to left/right  
.setCaptionLabel("")  
;  
//J3 controls  
cp5.addSlider(“j3Slider”)  
.setPosition(110, 440)  
.setSize(270, 30)  
.setRange(-162, 162)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
cp5.addButton(“j3JogMinus”)  
.setPosition(110, 493)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG-”)  
;  
cp5.addButton(“j3JogPlus”)  
.setPosition(290, 493)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG+”)  
;  
cp5.addNumberbox(“j3JogValue”)  
.setPosition(220, 493)  
.setSize(50, 30)  
.setRange(0, 20)  
.setFont(font)  
.setMultiplier(0.1)  
.setValue(1)  
.setDirection(Controller.HORIZONTAL) // change the control direction to left/right  
.setCaptionLabel("")  
;

//Z controls  
cp5.addSlider(“zSlider”)  
.setPosition(110, 565)  
.setSize(270, 30)  
.setRange(0, 150)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
cp5.addButton(“zJogMinus”)  
.setPosition(110, 618)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG-”)  
;  
cp5.addButton(“zJogPlus”)  
.setPosition(290, 618)  
.setSize(90, 40)  
.setFont(font)  
.setCaptionLabel(“JOG+”)  
;  
cp5.addNumberbox(“zJogValue”)  
.setPosition(220, 618)  
.setSize(50, 30)  
.setRange(0, 20)  
.setFont(font)  
.setMultiplier(0.1)  
.setValue(1)  
.setDirection(Controller.HORIZONTAL) // change the control direction to left/right  
.setCaptionLabel("")  
;

cp5.addTextfield(“xTextfield”)  
.setPosition(530, 205)  
.setSize(70, 40)  
.setFont(font)  
.setColor(255)  
.setCaptionLabel("")  
;  
cp5.addTextfield(“yTextfield”)  
.setPosition(680, 205)  
.setSize(70, 40)  
.setFont(font)  
.setColor(255)  
.setCaptionLabel("")  
;  
cp5.addTextfield(“zTextfield”)  
.setPosition(830, 205)  
.setSize(70, 40)  
.setFont(font)  
.setColor(255)  
.setCaptionLabel("")  
;

cp5.addButton(“move”)  
.setPosition(590, 315)  
.setSize(240, 45)  
.setFont(font)  
.setCaptionLabel(“MOVE TO POSITION”)  
;

cp5.addButton(“savePosition”)  
.setPosition(470, 520)  
.setSize(215, 50)  
.setFont(font2)  
.setCaptionLabel(“SAVE POSITION”)  
;

cp5.addButton(“run”)  
.setPosition(725, 520)  
.setSize(215, 50)  
.setFont(font2)  
.setCaptionLabel(“RUN PROGRAM”)  
;

cp5.addButton(“updateSA”)  
.setPosition(760, 590)  
.setSize(150, 40)  
.setFont(font)  
.setCaptionLabel("(Update)")  
;

cp5.addButton(“clearSteps”)  
.setPosition(490, 650)  
.setSize(135, 40)  
.setFont(font)  
.setCaptionLabel("(CLEAR)")  
;

//Z controls  
cp5.addSlider(“speedSlider”)  
.setPosition(490, 740)  
.setSize(180, 30)  
.setRange(500, 4000)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;

cp5.addSlider(“accelerationSlider”)  
.setPosition(720, 740)  
.setSize(180, 30)  
.setRange(500, 4000)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
cp5.addSlider(“gripperValue”)  
.setPosition(605, 445)  
.setSize(190, 30)  
.setRange(0, 100)  
.setColorLabel(#3269c2)  
.setFont(font)  
.setCaptionLabel("")  
;  
}

void draw() {  
background(#F2F2F2); // background black  
textSize(26);  
fill(33);  
text(“Forward Kinematics”, 120, 135);  
text(“Inverse Kinematics”, 590, 135);  
textSize(40);  
text(“SCARA Robot Control”, 260, 60);  
textSize(45);  
text(“J1”, 35, 250);  
text(“J2”, 35, 375);  
text(“J3”, 35, 500);  
text(“Z”, 35, 625);  
textSize(22);  
text(“Speed”, 545, 730);  
text(“Acceleration”, 745, 730);

//println("PREV: "+accelerationSlider);  
fill(speedSlider);  
fill(accelerationSlider);  
fill(j1Slider);  
fill(j2Slider);  
fill(j3Slider);  
fill(zSlider);  
fill(j1JogValue);  
fill(j2JogValue);  
fill(j3JogValue);  
fill(zJogValue);  
fill(gripperValue);

updateData();  
//println(data);

saveStatus=0; // keep savePosition variable 0 or false. See, when button SAVE pressed it makes the value 1, which indicates to store the value in the arduino code

// If slider moved, calculate new position of X,Y and Z with forward kinematics  
if (slider1Previous != j1Slider) {  
if (activeIK == false) { // Check whether the inverseKinematics mode is active, Executre Forward kinematics only if inverseKinematics mode is off or false  
theta1 = round(cp5.getController(“j1Slider”).getValue()); // get the value from the slider1  
theta2 = round(cp5.getController(“j2Slider”).getValue());  
forwardKinematics();  
myPort.write(data);  
}  
}  
slider1Previous = j1Slider;

if (slider2Previous != j2Slider) {  
if (activeIK == false) { // Check whether the inverseKinematics mode is active, Executre Forward kinematics only if inverseKinematics mode is off or false  
theta1 = round(cp5.getController(“j1Slider”).getValue()); // get the value from the slider1  
theta2 = round(cp5.getController(“j2Slider”).getValue());  
forwardKinematics();  
myPort.write(data);  
}  
}  
slider2Previous = j2Slider;

if (slider3Previous != j3Slider) {  
if (activeIK == false) { // Check whether the inverseKinematics mode is active, Executre Forward kinematics only if inverseKinematics mode is off or false  
theta1 = round(cp5.getController(“j1Slider”).getValue()); // get the value from the slider1  
theta2 = round(cp5.getController(“j2Slider”).getValue());  
forwardKinematics();  
myPort.write(data);  
}  
}  
slider3Previous = j3Slider;

if (sliderzPrevious != zSlider) {  
if (activeIK == false) { // Check whether the inverseKinematics mode is active, Executre Forward kinematics only if inverseKinematics mode is off or false  
zP = round(cp5.getController(“zSlider”).getValue());  
myPort.write(data);  
}  
}  
sliderzPrevious = zSlider;

if (gripperValuePrevious != gripperValue) {  
if (activeIK == false) { // Check whether the inverseKinematics mode is active, Executre Forward kinematics only if inverseKinematics mode is off or false  
gripperAdd = round(cp5.getController(“gripperValue”).getValue());  
gripperValue=gripperAdd+50;  
updateData();  
println(data);  
myPort.write(data);  
}  
}  
gripperValuePrevious = gripperValue;  
activeIK = false; // deactivate inverseKinematics so the above if statements can be executed the next interation

fill(33);  
textSize(32);  
text("X: ", 500, 290);  
text(xP, 533, 290);  
text("Y: ", 650, 290);  
text(yP, 685, 290);  
text("Z: ", 800, 290);  
text(zP, 835, 290);  
textSize(26);  
text(“Gripper”, 650, 420);  
text(“CLOSE”, 510, 470);  
text(“OPEN”, 810, 470);  
textSize(18);

if (positionsCounter \>0 ) {  
text(positions[positionsCounter-1], 460, 630);  
text(“Last saved position: No.”+(positionsCounter-1), 460, 600);  
} else {  
text(“Last saved position:”, 460, 600);  
text(“None”, 460, 630);  
}  
}

// FORWARD KINEMATICS  
void forwardKinematics() {  
float theta1F = theta1 \* PI / 180; // degrees to radians  
float theta2F = theta2 \* PI / 180;  
xP = round(L1 \* cos(theta1F) + L2 \* cos(theta1F + theta2F));  
yP = round(L1 \* sin(theta1F) + L2 \* sin(theta1F + theta2F));  
}

// INVERSE KINEMATICS  
void inverseKinematics(float x, float y) {  
theta2 = acos((sq(x) + sq(y) - sq(L1) - sq(L2)) / (2 \* L1 \* L2));  
if (x \< 0 & y \< 0) {  
theta2 = (-1) \* theta2;  
}

theta1 = atan(x / y) - atan((L2 \* sin(theta2)) / (L1 + L2 \* cos(theta2)));

theta2 = (-1) \* theta2 \* 180 / PI;  
theta1 = theta1 \* 180 / PI;

// Angles adjustment depending in which quadrant the final tool coordinate x,y is  
if (x \>= 0 & y \>= 0) { // 1st quadrant  
theta1 = 90 - theta1;  
}  
if (x \< 0 & y \> 0) { // 2nd quadrant  
theta1 = 90 - theta1;  
}  
if (x \< 0 & y \< 0) { // 3d quadrant  
theta1 = 270 - theta1;  
phi = 270 - theta1 - theta2;  
phi = (-1) \* phi;  
}  
if (x \> 0 & y \< 0) { // 4th quadrant  
theta1 = -90 - theta1;  
}  
if (x \< 0 & y == 0) {  
theta1 = 270 + theta1;  
}

// Calculate “phi” angle so gripper is parallel to the X axis  
phi = 90 + theta1 + theta2;  
phi = (-1) \* phi;

// Angle adjustment depending in which quadrant the final tool coordinate x,y is  
if (x \< 0 & y \< 0) { // 3d quadrant  
phi = 270 - theta1 - theta2;  
}  
if (abs(phi) \> 165) {  
phi = 180 + phi;  
}

theta1=round(theta1);  
theta2=round(theta2);  
phi=round(phi);

cp5.getController(“j1Slider”).setValue(theta1);  
cp5.getController(“j2Slider”).setValue(theta2);  
cp5.getController(“j3Slider”).setValue(phi);  
cp5.getController(“zSlider”).setValue(zP);  
}

void controlEvent(ControlEvent theEvent) {

if (theEvent.isController()) {  
println(theEvent.getController().getName());  
}  
}

public void xTextfield(String theText) {  
//If we enter a value into the Textfield, read the value, convert to integer, set the inverseKinematics mode active  
xP=Integer.parseInt(theText);  
activeIK = true;  
inverseKinematics(xP, yP); // Use inverse kinematics to calculate the J1(theta1), J2(theta2), and J3(phi) positions  
//activeIK = false;  
println("Test; theta1: “+theta1+” theta2: "+theta2);  
}  
public void yTextfield(String theText) {  
yP=Integer.parseInt(theText);  
activeIK = true;  
inverseKinematics(xP, yP);  
//activeIK = false;  
}  
public void zTextfield(String theText) {  
zP=Integer.parseInt(theText);  
activeIK = true;  
inverseKinematics(xP, yP);  
}

public void j1JogMinus() {  
int a = round(cp5.getController(“j1Slider”).getValue());  
a=a-j1JogValue;  
cp5.getController(“j1Slider”).setValue(a);  
}  
//J1 control  
public void j1JogPlus() {  
int a = round(cp5.getController(“j1Slider”).getValue());  
a=a+j1JogValue;  
cp5.getController(“j1Slider”).setValue(a);  
}  
//J2 control  
public void j2JogMinus() {  
int a = round(cp5.getController(“j2Slider”).getValue());  
a=a-j2JogValue;  
cp5.getController(“j2Slider”).setValue(a);  
}  
public void j2JogPlus() {  
int a = round(cp5.getController(“j2Slider”).getValue());  
a=a+j2JogValue;  
cp5.getController(“j2Slider”).setValue(a);  
}  
//J3 control  
public void j3JogMinus() {  
int a = round(cp5.getController(“j3Slider”).getValue());  
a=a-j3JogValue;  
cp5.getController(“j3Slider”).setValue(a);  
}  
public void j3JogPlus() {  
int a = round(cp5.getController(“j3Slider”).getValue());  
a=a+j3JogValue;  
cp5.getController(“j3Slider”).setValue(a);  
}  
//J3 control  
public void zJogMinus() {  
int a = round(cp5.getController(“zSlider”).getValue());  
a=a-zJogValue;  
cp5.getController(“zSlider”).setValue(a);  
}  
public void zJogPlus() {  
int a = round(cp5.getController(“zSlider”).getValue());  
a=a+zJogValue;  
;  
cp5.getController(“zSlider”).setValue(a);  
}

public void move() {

myPort.write(data);  
println(data);  
}

public void savePosition() {  
// Save the J1, J2, J3 and Z position in the array  
positions[positionsCounter]=“J1=”+str(round(cp5.getController(“j1Slider”).getValue()))  
+"; J2=" + str(round(cp5.getController(“j2Slider”).getValue()))  
+"; J3="+str(round(cp5.getController(“j3Slider”).getValue()))  
+"; Z="+str(round(cp5.getController(“zSlider”).getValue()));  
positionsCounter++;  
saveStatus = 1;  
updateData();  
myPort.write(data);  
saveStatus=0;  
}

public void run() {

if (runStatus == 0) {  
cp5.getController(“run”).setCaptionLabel(“STOP”);  
cp5.getController(“run”).setColorLabel(#e74c3c);

```
runStatus = 1;

```

} else if (runStatus == 1) {  
runStatus = 0;  
cp5.getController(“run”).setCaptionLabel(“RUN PROGRAM”);  
cp5.getController(“run”).setColorLabel(255);  
}  
updateData();  
myPort.write(data);  
}  
public void updateSA() {  
myPort.write(data);  
}  
public void clearSteps() {  
saveStatus = 2; // clear all steps / program  
updateData();  
myPort.write(data);  
println("Clear: "+data);  
positionsCounter=0;  
saveStatus = 0;  
}

public void updateData() {  
data = str(saveStatus)  
+","+str(runStatus)  
+","+str(round(cp5.getController(“j1Slider”).getValue()))  
+","+str(round(cp5.getController(“j2Slider”).getValue()))  
+","+str(round(cp5.getController(“j3Slider”).getValue()))  
+","+str(round(cp5.getController(“zSlider”).getValue()))  
+","+str(gripperValue)  
+","+str(speedSlider)  
+","+str(accelerationSlider);  
}