# Processing arduino slave from raspberry pi

**URL:** <https://discourse.processing.org/t/processing-arduino-slave-from-raspberry-pi/18883>\
**Category:** Processing for Pi\
**Created:** [March 21, 2020, 5:47pm UTC](https://discourse.processing.org/t/processing-arduino-slave-from-raspberry-pi/18883 "2020-03-21T17:47:00Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![glv](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/glv/32/18785_2.png) [@glv](https://discourse.processing.org/u/glv)\
**Post date:** [March 21, 2020, 8:16pm UTC](https://discourse.processing.org/t/processing-arduino-slave-from-raspberry-pi/18883/3 "2020-03-21T20:16:59Z")

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Hello,

Are you connected to the correct serial port?

Try a simple example that just turns an LED on and off and watch the Rx lights on the Arduino side.

> [@Processing to Arduino Serial Library Example](https://discourse.processing.org/t/processing-to-arduino-serial-library-example/11143):
>
> The SimpleWrite example in the Processing examples was not working on PCs I had available to me. The Arduino resets when establishing a serial connection. I added a delay(1000) to allow the Arduino to reset after serial connection to Processing and it now works. I modified the Processing setup() as follows: void setup() { size(200, 200); printArray(Serial.list()); //Added! List all the available serial ports String portName = Serial.list()[0]; myPort = new Serial(this, portNa…

I use [serial pass through](https://www.arduino.cc/en/Tutorial/SerialPassthrough) on receiving Arduino and a “USB-to-TTL serial adapter” to monitor communications between devices when doing development.

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_[View the full topic](https://discourse.processing.org/t/processing-arduino-slave-from-raspberry-pi/18883)._