Hello !
I am completely new here and also new to node red & RaspberryPi in general, so I need some help of you.
I want to connect the two sensors MH-Z19 & SDS011 to my RaspberryPi4B to show their data on the node red dashboard and have some problems with it.
First to the MH-Z19, the node red website tells me that i have to enable the serial port in raspi-config. I did that but i constanly get this report when i try to get the co2 data in the debug window.
"Error Resource temporarily unavailable Cannot lock port". I got a hint that I shoul disable bluetooth, i did that too but get the same report.
I connected the SDS011 via USB to my Raspberry PI and the node itself says "connected" under it, but i cant get any information from it in the debug window. I get the report " TypeError: Cannot read property 'command' of undefined". I think its a problem with the infject node, but i am not sure.
What i noticed, is that both of the Sensors use the same serialport, /dev/serial0 in the properties.
Of curse i tried to use the sensors separtately, but i still get the same reports.
I have a feeling that these problems are easy to solve, but because this program is totaly new for me in general, I just don't get it.
So i hope someone here can help me with it.
As for the MH-Z17: Yes, I Connected the it just like it's told on the website. The sensor itself also blinks when connected. I think i get the report because the /dev/serial0 is already used, is there any way to show all the serial or URAT connections of the Pi to see wich one i should disable that the MH-Z19 can work? Or is the report i get a common one and there is another way to make it work?
As for the sds011, how do i do that? I'm a total beginner, how do i access the device with python and how do i get to the exec node ?
First off, please add an explaination of what you did to get the MH-Z17 to work for the benefit of others that might run into this issue.
The best thing to do is a google search and try the existing projects. Once you get it working outside of node red, you can try runing the program using the exec node.
Also I recommend watching this playlist: Node-RED Essentials. The videos are done by the developers of node-red. They're nice & short and to the point. You will understand a whole lot more in about 1 hour. A small investment for a lot of gain.
I just switched the node I installed.
They are two different nodes to download on node red for the mh-z19. I used the green one all the time but the light red one is the one to use.
I found this for the sds011, but i don't know how to use this information.
Do i have to create a script and copy paste things from this github or what should i do ? And if yes, where should i save this script on my pi ?
Hope someone can help me.
Green ones are flows someone has added to the library, red ones are the contributed node itself.
As for the Py-sds011, that is a python interface to the sensor. It also hasn’t been updated in three years and it doesn’t look like the author is responding to issues so it may be abandoned.
