neopixel 0.1.1 stopped / TypeError: Cannot read property 'stdin' of null

Which node are you reporting an issue on?

node-red-node-pi-neopixel

What are the steps to reproduce?

on a raspberry pi running buster:
curl -sS get.pimoroni.com/unicornhat | bash
npm install node-red-node-pi-neopixel
create an inject node with msg.payload (text) of red,8 for example
connect it to a configured neopixel node (pin 12, 8 pixels strip)
deploy and click inject node

What happens?

on deploy, neopixel node shows "stopped"
on inject, debug shows: "TypeError: Cannot read property 'stdin' of null"
node-red-log shows same as debug, no other errors for neopixel

What do you expect to happen?

8 red leds to light up on clicking the inject node

Please tell us about your environment:

• neopixel node version: 0.1.1
• Node-RED version: v1.2.6
• node.js version: v12.20.0
• npm version: 6.1448
• Platform/OS: raspbperry pi / debian 10 buster
• Browser: n/a

I did find the other issue [(] where a similar thing happened but it doesn't help. I'm not running docker.

I did run the command

./neopix 1 40 pcent 100 true

and this comes back:

Traceback (most recent call last):
  File "./neopix.py", line 50, in <module>
    LED_CHANNEL = int(sys.argv[6])
IndexError: list index out of range

I have tried other pins but same thing.

Note: the 8 led strip works with the unicorn hat simple.py (my 8 pixels light up pinky-purple)

Also note it works on another pi running buster and nodered v1.2.6 at neopixel version 0.0.25

Start by reproducing the failure with node-red-node-pi-neopixel 0.1.1 on the reported Raspberry Pi setup, then inspect the neopixel node and the referenced ./neopix.py entry point. Compare behavior with version 0.0.25 and check why the process is null before stdin is accessed. Done means the node stays running and the reported red,8 payload lights the eight LEDs.