# Hidraw0 RPi3 vs RPi4

**URL:** <https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035>\
**Category:** General\
**Created:** [1 May 2022 17:43 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035 "2022-05-01T17:43:00Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![JFPP](https://avatars.discourse-cdn.com/v4/letter/j/278dde/32.png) [@JFPP](https://discourse.nodered.org/u/JFPP)\
**Post date:** [1 May 2022 17:43 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035/1 "2022-05-01T17:43:01Z")

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Hi there,

This is my first post. I am quite new on Node-Red, Linux & Raspberry Pi and I need your support.

I have an application running with a RPi3. I am building a new project with RPi4 and I want to reuse quite a few things and almost everyting is working just fine, except a device that I have it connected to one of the USB ports.

In the RPi3 I have an "Edit exec node" with:

sudo chmod 666 /dev/hidraw0

this is to stablish the initial connection. Then I also have several "Edit exec nodes" with the same command (just changing some sintax for different control messages) like:

sudo echo -e '\x00\x00\x00\x00\x00\x13\x00\x00\x00' \> /dev/hidraw0

Like I said, the above works fine on the RPi3 but not on the RPi4.  
I have tried similar approach with different values for hidraw\* and dev/ttyUSB\* after checking with lsusb that indeed the usb device is seen by the RPi4.

I hope some of you might have some suggestions that would help me to solve this issue.

THANKS in advance.

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**Author:** ![hardillb](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/hardillb/32/12373_2.png) [@hardillb](https://discourse.nodered.org/u/hardillb)\
**Post date:** [2 May 2022 15:49 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035/2 "2022-05-02T15:49:53Z")

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Look at udev rules to

1. Identify the correct device
2. Assign a fixed symbolic name to the now identified device

Search the site, there will be examples using serial ports you can use as a starting point

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**Author:** ![JFPP](https://avatars.discourse-cdn.com/v4/letter/j/278dde/32.png) [@JFPP](https://discourse.nodered.org/u/JFPP)\
**Post date:** [4 May 2022 17:13 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035/3 "2022-05-04T17:13:13Z")

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Thanks for your suggestions.  
I will look into it next week again and I hope I will manage to get it working this time.

Thanks again.

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**Author:** ![JFPP](https://avatars.discourse-cdn.com/v4/letter/j/278dde/32.png) [@JFPP](https://discourse.nodered.org/u/JFPP)\
**Post date:** [5 May 2022 10:17 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035/4 "2022-05-05T10:17:34Z")

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> [@hardillb](#):
>
> udev rules

You really pointed me in the right direction. I have now solved the issue. Big thanks.

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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:** [19 May 2022 10:18 UTC](https://discourse.nodered.org/t/hidraw0-rpi3-vs-rpi4/62035/5 "2022-05-19T10:18:02Z")

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