# uDMX / usb issue

**URL:** <https://discourse.nodered.org/t/udmx-usb-issue/2782>\
**Category:** General\
**Created:** [2 September 2018 18:18 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782 "2018-09-02T18:18:35Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![RogierQ](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rogierq/32/3211_2.png) [@RogierQ](https://discourse.nodered.org/u/RogierQ)\
**Post date:** [2 September 2018 18:18 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782/1 "2018-09-02T18:18:35Z")

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I try to make udmx working on my raspberry nr installation.  
but i cannot get it to work.

first i installed udmx, without succes. show not found below node

then had contacted the developer, he helped me with an extra instruction to install sudo apt-get install build-essential libudev-dev

same result

then i saw i needed to install it before connecting the usb  
so i made a new clean instal but again not found message  
when i check the node-red log i goves the messages  
[error] [udmx:b43b74cc.dc3b5] Error: LIBUSB\_ERROR\_ACCESS

surfed around the web and did not find a solution

any one any idea how to get this solved?  
the usb id is correct so that should be ok  
only thing i found is rights things but my knowledge i to low to understand how and what about this

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**Author:** ![ceejm1](https://avatars.discourse-cdn.com/v4/letter/c/53a042/32.png) [@ceejm1](https://discourse.nodered.org/u/ceejm1)\
**Post date:** [4 June 2020 19:44 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782/2 "2020-06-04T19:44:46Z")

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> [@RogierQ](#):
>
> sudo apt-get install build-essential libudev-dev

Hello,

Did you ever manage to fix this? I'm coming up against the same problem...

James

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [4 June 2020 21:08 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782/3 "2020-06-04T21:08:30Z")

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You probably need to do something like these suggestions to run as a non-root user

> <https://askubuntu.com/questions/978552/how-do-i-make-libusb-work-as-non-root>

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**Author:** ![ceejm1](https://avatars.discourse-cdn.com/v4/letter/c/53a042/32.png) [@ceejm1](https://discourse.nodered.org/u/ceejm1)\
**Post date:** [4 June 2020 22:37 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782/4 "2020-06-04T22:37:33Z")

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Thank you for the pointer. Thats done the trick!!

Cheers!

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [18 June 2020 22:37 UTC](https://discourse.nodered.org/t/udmx-usb-issue/2782/5 "2020-06-18T22:37:37Z")

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