# Problem connection Processing Arduino

**URL:** <https://discourse.processing.org/t/problem-connection-processing-arduino/12700>\
**Category:** Electronics (Arduino, etc.)\
**Created:** [July 13, 2019, 1:21pm UTC](https://discourse.processing.org/t/problem-connection-processing-arduino/12700 "2019-07-13T13:21:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![bking](https://avatars.discourse-cdn.com/v4/letter/b/dc4da7/32.png) [@bking](https://discourse.processing.org/u/bking)\
**Post date:** [July 13, 2019, 1:21pm UTC](https://discourse.processing.org/t/problem-connection-processing-arduino/12700/1 "2019-07-13T13:21:44Z")

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Hi,

When I start my program Processing to read data from Arduino, I see this error message

```auto
[0] "/dev/cu.BeatsPill-SPPDev-1"
[1] "/dev/cu.Bluetooth-Incoming-Port"
[2] "/dev/cu.JBLFlip3-SPPDev"
[3] "/dev/cu.UEBOOM-LWACP"
[4] "/dev/cu.usbmodem14201"
[5] "/dev/tty.BeatsPill-SPPDev-1"
[6] "/dev/tty.Bluetooth-Incoming-Port"
[7] "/dev/tty.JBLFlip3-SPPDev"
[8] "/dev/tty.UEBOOM-LWACP"
[9] "/dev/tty.usbmodem14201"
map(NaN, 0, 2774, 0, 36) called, which returns NaN (not a number)
Error, disabling serialEvent() for /dev/cu.usbmodem14201
null

```

So to fix the problem, I unplugged the usb serial port, I plug it and re-start my program in Processing.

Then, I can receive my datas.  
An other problem is : why I have twice my port Arduino (/dev/tty.usbmodem14201) red in Processing, to the port 4 and the port 9?

---

<div class="post-metadata">

**Author:** ![kll](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/kll/32/964_2.png) [@kll](https://discourse.processing.org/u/kll)\
**Post date:** [July 13, 2019, 2:11pm UTC](https://discourse.processing.org/t/problem-connection-processing-arduino/12700/2 "2019-07-13T14:11:10Z")

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why you not show the console print of the raw data what come from arduino?  
then it might be more easy to understand why your text split to float array conversion fails at arduino boot

* * *

did you notice that all devices are listed double, as /dev/cu/ and /dev/tty  
what operating system you use?  
possibly read

> <https://stackoverflow.com/questions/37688257/choosing-between-dev-tty-usbserial-vs-dev-cu-usbserial>