# Node-red on Pi not showing the Serial USBs

**URL:** <https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945>\
**Category:** Hardware\
**Tags:** node-red-node-serialport\
**Created:** [25 June 2024 19:57 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945 "2024-06-25T19:57:53Z")\
**Posts on this page:** 12\
**Page:** 1

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**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [25 June 2024 19:57 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/1 "2024-06-25T19:57:53Z")

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Hello;  
I am new to raspi, and I have a problem getting data from my Arduino board, which is connected via USB to the Pi. I used to connect the Arduino to a Nod-red installed on a PC, and it works very well. I have got the reTerminal DM (HMI based on Raspi), and I installed the Node-red on it. Everything about Node works very well, including graphs and all nodes. However, the Serial node does not show my serial USBs. I searched the internet to find out the problem. The Arduino Giga sounds like it is seen by the pi, but nothing comes to the nod-red to get a reading from it. The /dev/ttyS0 is not the Giga board. I even tried to test it, but nothing was received. I connected the Arduino back to the PC, and everything was okay.  
Please see the pictures, and thanks for your patience.

 ![Screenshot 2024-06-25 at 8.39.53 pm](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/d/cdbd3cb69d1539251f7778a09dbaa92159646d8b.jpeg)

![Screenshot 2024-06-25 at 8.40.28 pm](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/b/1b4a0b76453eb1783d9bdadcba74ec33ecc75e95.jpeg)

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [25 June 2024 20:29 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/2 "2024-06-25T20:29:10Z")

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If you unplug the usb serial and run `ls /dev/tty*` again is anything missing? Possibly one of the /dev/ttyCH343USB entries?

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**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [25 June 2024 20:36 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/3 "2024-06-25T20:36:14Z")

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Thank you for your reply. I tried this also, and nothing changed. Both /dev/ttyCH343USB0 and /dev/ttyCH343USB1 are there with and without USB connection.

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [25 June 2024 21:09 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/4 "2024-06-25T21:09:47Z")

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In that case run  
`tail -f /var/log/syslog`  
then plug/unplug the serial usb and see what appears in the log.

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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:** [26 June 2024 07:32 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/5 "2024-06-26T07:32:57Z")

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or `journalctl -f`

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [26 June 2024 07:59 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/6 "2024-06-26T07:59:21Z")

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> [@hardillb](#):
>
> journalctl -f

That is correct, using journalctl is a better way to do it as not all systems will log to syslog.

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<div class="post-metadata">

**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [26 June 2024 09:43 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/7 "2024-06-26T09:43:31Z")

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Thank you @Colin and @hardillb. When I return to the lab, I will check them and share any results. I appreciate your help.

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**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [26 June 2024 11:19 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/8 "2024-06-26T11:19:09Z")

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> [@hardillb](#):
>
> or `journalctl -f`

Hello,  
This is the log response when I connect and disconnect the Arduino board from the USB. By the way, the terminal uses a Pi CM4, if this makes any difference.

```auto
-name="new target" error="Get \"http://192.168.0.72:8086/metrics\": dial tcp 192.168.0.72:8086: i/o timeout"
Jun 26 12:14:34 pi kernel: usb 1-1.1: new full-speed USB device number 9 using xhci-hcd
Jun 26 12:14:34 pi kernel: usb 1-1.1: New USB device found, idVendor=2341, idProduct=0266, bcdDevice= 1.01
Jun 26 12:14:34 pi kernel: usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jun 26 12:14:34 pi kernel: usb 1-1.1: Product: Giga
Jun 26 12:14:34 pi kernel: usb 1-1.1: Manufacturer: Arduino
Jun 26 12:14:34 pi kernel: usb 1-1.1: SerialNumber: 0031003E3033510C34323437
Jun 26 12:14:35 pi mtp-probe[2774]: checking bus 1, device 9: "/sys/devices/platform/scb/fe9c0000.xhci/usb1/1-1/1-1.1"
Jun 26 12:14:35 pi mtp-probe[2774]: bus: 1, device: 9 was not an MTP device
Jun 26 12:14:35 pi mtp-probe[2777]: checking bus 1, device 9: "/sys/devices/platform/scb/fe9c0000.xhci/usb1/1-1/1-1.1"
Jun 26 12:14:35 pi mtp-probe[2777]: bus: 1, device: 9 was not an MTP device
Jun 26 12:14:41 pi influxd-systemd-start.sh[1562]: ts=2024-06-26T11:14:41.994897Z lvl=error msg="Unable to gather" log_id=0q13JddW000 service=scraper scraper-name="new target" error="Get \"http://192.168.0.72:8086/metrics\": dial tcp 1

```

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<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [26 June 2024 12:17 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/9 "2024-06-26T12:17:41Z")

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The pi is not recognising the device as a serial device. It would say in the log if it did and where it was mounted.  
Do you have to do something on the Giga to configure it as serial?

Otherwise I think you will need to try elsewhere for the cause, it isn't a node-red problem obviously.

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<div class="post-metadata">

**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [27 June 2024 11:28 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/10 "2024-06-27T11:28:38Z")

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Thanks for your reply.

I opened an issue ticket with the reTrminal DM maker, and it may only recognise Tx and Rx directly to the GPIO pins, so I ordered a USB to RS485 adapter. I will see how it works.

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<div class="post-metadata">

**Author:** ![Hayder](https://avatars.discourse-cdn.com/v4/letter/h/47e85d/32.png) [@Hayder](https://discourse.nodered.org/u/Hayder)\
**Post date:** [11 July 2024 21:39 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/11 "2024-07-11T21:39:07Z")

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Hi,

I solved the problem. It sounds like the drivers that shall be installed for the terminal DM conflict with the USB type for the pi; I found in the driver file they added somehow (I am not good at explaining it ), not the ACM type but CH34, which is not the one on the hardware. However, I took the lines to install any USB drivers in that driver file, and it works now.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [25 July 2024 21:40 UTC](https://discourse.nodered.org/t/node-red-on-pi-not-showing-the-serial-usbs/88945/12 "2024-07-25T21:40:00Z")

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