# Button Raspberry Pi
**URL:** https://discourse.processing.org/t/button-raspberry-pi/1823
**Category:** Processing for Pi
**Created:** [July 16, 2018, 5:30pm UTC](https://discourse.processing.org/t/button-raspberry-pi/1823 "2018-07-16T17:30:35Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@EllenBogen](https://discourse.processing.org/u/EllenBogen)
#### Post date: [July 16, 2018, 5:30pm UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/1 "2018-07-16T17:30:36Z")
Hi,
I´m a beginner in using the raspberry pi. I am trying to set up a button to turn on an image and have a black screen, if the button is not pushed.
To start with simple Code, I startet with changing between two color:
black = button not pushed
red = button pushed
BUT always when the button is bushed a flickering between both colors starts. What did I do wrong? I believe the wiring is right, because it is very simple (GND & GPIO 17).
Code:
import [processing.io](http://processing.io).\*;
void setup() {
// set pin 4 as an input:
GPIO.pinMode(17, GPIO.INPUT);
}
void draw() {
if (GPIO.digitalRead(17) == GPIO.HIGH) { // if the pin is HIGH, the button isn’t pressed
```
// set the background to black:
background(0, 0, 0);
```
} else { // if the button is pressed:
```
// set the background to red:
background(255, 0, 0);
```
}
}
---
### Author:  [@colouredmirrorball](https://discourse.processing.org/u/colouredmirrorball)
#### Post date: [July 16, 2018, 6:04pm UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/2 "2018-07-16T18:04:50Z")
Could you draw a schematic of your wiring nonetheless?
---
### Author:  [@kfrajer](https://discourse.processing.org/u/kfrajer)
#### Post date: [July 16, 2018, 10:16pm UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/3 "2018-07-16T22:16:09Z")
No R-pi here to test. One approach is to update only when you detect a change of button state. You continuosly check if the button is pressed. If it changes to pressed, update your memory field, update your background and keep checking. If you detect a change, the button is disengaged, you update your memory field, you change the background, and you keep checking.
The memory field could be something as simple as a boolean variable in the global scope.
Another approach is to use `noLoop()`/`redraw()` approach. Check the reference to understand their implementations.
Kf
---
### Author:  [@gohai](https://discourse.processing.org/u/gohai)
#### Post date: [July 17, 2018, 2:31am UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/4 "2018-07-17T02:31:04Z")
Hi @EllenBogen - using physical buttons was just covered in a tutorial on our website, have a look here: [https://pi.processing.org/tutorial/visual-synth/](https://pi.processing.org/tutorial/visual-synth/)
Perhaps using `GPIO.INPUT_PULLUP` helps!
---
### Author:  [@EllenBogen](https://discourse.processing.org/u/EllenBogen)
#### Post date: [July 17, 2018, 8:34am UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/5 "2018-07-17T08:34:16Z")
Thank you so much. The PULLUP command worked.
---
### Author:  [@Afflospark](https://discourse.processing.org/u/Afflospark)
#### Post date: [April 14, 2019, 6:58pm UTC](https://discourse.processing.org/t/button-raspberry-pi/1823/6 "2019-04-14T18:58:40Z")
haha, that was too easy.
That’s ok if you are a beginner, but have you ever think about controlling raspberry pi using WhatsApp?
Try to do the same light experiment by sending a command to raspberry pi using WhatsApp.
You can take help from this [Control Raspberry pi with whatsapp](https://www.experthoot.com/how-to-control-a-raspberry-pi-using-whatsapp/)