# Just want to check on these three errors

**URL:** <https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039>\
**Category:** General\
**Created:** [9 June 2020 10:03 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039 "2020-06-09T10:03:35Z")\
**Posts on this page:** 11\
**Page:** 1

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 10:03 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/1 "2020-06-09T10:03:35Z")

</div>

I had to restart NR on a machine.

Seeing these errors when it is starting:

```auto
9 Jun 19:56:11 - [info] Loading palette nodes
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: No module named rpi_ws281x

While constructing LEDNode widget: TypeError: Cannot read property 'config' of null
    at addWidget (/home/pi/.node-red/node_modules/node-red-dashboard/index.js:72:39)
    at Object.addWidget (/home/pi/.node-red/node_modules/node-red-dashboard/index.js:136:48)
    at new LEDNode (/home/pi/.node-red/node_modules/node-red-contrib-ui-led/led.js:41:28)
    at Object.createNode (/usr/lib/node_modules/node-red/node_modules/@node-red/runtime/lib/nodes/flows/util.js:483:31)
    at Flow.start (/usr/lib/node_modules/node-red/node_modules/@node-red/runtime/lib/nodes/flows/Flow.js:189:48)
    at start (/usr/lib/node_modules/node-red/node_modules/@node-red/runtime/lib/nodes/flows/index.js:329:33)
    at tryCatchReject (/usr/lib/node_modules/node-red/node_modules/when/lib/makePromise.js:845:30)
    at runContinuation1 (/usr/lib/node_modules/node-red/node_modules/when/lib/makePromise.js:804:4)
    at Fulfilled.when (/usr/lib/node_modules/node-red/node_modules/when/lib/makePromise.js:592:4)
    at Pending.run (/usr/lib/node_modules/node-red/node_modules/when/lib/makePromise.js:483:13)

```

I can't find a rpi\_ws281x in my pallette.

The second one:  
That is a bit weird.  
But it is that a `null` has been sent to the `LED` node - thinking?

Ok, another one snuck in:

```auto
pam_unix(sudo:session): session closed for user root
      pi : TTY=unknown ; PWD=/home/pi ; USER=root ; COMMAND=/sbin/iwlist wlan0 scan

```

I'm looking at it, but may need help.

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [9 June 2020 10:05 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/2 "2020-06-09T10:05:51Z")

</div>

both are related.

ws281x = LED.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 10:07 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/3 "2020-06-09T10:07:10Z")

</div>

Ok. Thanks.

I have the `ui_LED` node also installed. So anyway....

How would this be happening?

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 10:09 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/4 "2020-06-09T10:09:03Z")

</div>

On the third one:

```auto
pi@TelePi:~/.node-red $ /sbin/iwlist wlan0 scan
wlan0 Scan completed :
          Cell 01 - Address: 24:F5:A2:B2:2A:07
                    Channel:6
                    Frequency:2.437 GHz (Channel 6)
                    Quality=54/70 Signal level=-5
.
.
.
.

```

It works. So why would it be failing?

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [9 June 2020 10:13 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/5 "2020-06-09T10:13:41Z")

</div>

> [@Trying\_to\_learn](#):
>
> ImportError: No module named rpi\_ws281x  
> ...  
> I can't find a rpi\_ws281x in my pallette.

Someone creates a node for node-red. this node has dependencies where they `import` a module, in this case rpi\_ws281x. Module rpi\_ws281x cannot be found, this has implications: node-red will crash when trying to use that node.

I made the bad assumption that they are related, they are not - my apologies. You are using the dashboard ui\_led node which is for visuals.

Do you have a node installed to control ws281x LEDs ?

The wlan command requires sudo/root for certain features of the command which could be the issue.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 10:20 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/6 "2020-06-09T10:20:08Z")

</div>

> [@bakman2](#):
>
> Do you have a node installed to control ws281x LEDs ?

AKAIK, no. ☹

I checked my palette and there is no node for them that I can see.

> [@bakman2](#):
>
> The wlan command requires sudo/root for certain features of the command which could be the issue.

Interesting.

The command that does that runs every 40 seconds. I found it in the flow and it is giving valid output.

On the log, it was every few seconds.

---

<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:** [9 June 2020 10:31 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/7 "2020-06-09T10:31:41Z")

</div>

Did you only restart node-red or did you do something else too?

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 10:36 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/8 "2020-06-09T10:36:28Z")

</div>

I edited a rogue node, but that was nothing to do with the errors.

I was (am) messing around with `CSS` and I goofed.  
The node went _rogue_ and I had to stop Node-red and start it in `--safe` mode.

After fixing the problem I started Node-Red again and saw the error.

---

<div class="post-metadata">

**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:** [9 June 2020 13:45 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/9 "2020-06-09T13:45:18Z")

</div>

ws281x is from some physical LED node - maybe neopixel ?  
It is actually the python library so maybe the pre-reqs for the node are not installed.  
(or indeed the node needs to be removed)

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [9 June 2020 21:39 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/10 "2020-06-09T21:39:13Z")

</div>

Curiouser and curiouser.

Thanks.

Further investigation required this end.

---

<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:** [8 August 2020 21:39 UTC](https://discourse.nodered.org/t/just-want-to-check-on-these-three-errors/28039/11 "2020-08-08T21:39:18Z")

</div>

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