Hello, I am using Node-red over "Pi". I have the "dht21-AM2301" sensor. How can I communicate with node-red by connecting the sensor to the Pi.

Your inject mode is passing "~/nemm.py". Your Exec node has "python3",, Append Payload is ticked and the field for additional parameters has "~/nem.py". So is it nem.py or nemm.py? You can pass the name of the script in msg.payload OR you can specify it in the Exec node but not both. It is wron…

I tried but the pi crashes and becomes unresponsive.

I see that the node hasn't been updated for a while and also requires superuser permissions. I would remove the node.

I would recommend that you get hold of another sensor, that has contrib nodes available. The SHT3x or BMExxx type sensors would be a good choice. Also remember that having sensors directly connected to a Pi means that you are limited as to where you can place them. Most people connect these senso…

The DHT21 = AM2301 = AHT20 (?) does seem to be much less common than the DHT11 or 22. If it is the same device as the AHT20 then this page may help you get it working from the Raspberry Pi command line. Adafruit tutorials are usually very good.

[image] I don't want to use different devices because they are close. It is easier for me to read the temperature on a single device. My codes are working on the Pi, I just need to get the data.

One way is to call your python script from an exec node. You might want to change the script so it prints one set of values and exits. Then you can call it from exec at whatever interval you like. The output data will go into msg.payload. Alternatively have the script publish the readings by mqtt a…

"python dht_simpletest.py" in console " python dht_simpletest.py I run it with the " command. I don't understand how to do it in "exec". Can you help?

Whatever you type at the command line you can put in the "Command" field of the Exec node, though it is wise to use full pathnames, eg "/usr/bin/python3 /home/pi/dht_simpletest.py" So a Node-Red flow for testing might consist of an inject node to start the flow, exec and debug. [Untitled 2] [{"i…

If you want help to find out why it would be a good idea to post your flow, your script and whatever error messages you get.

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Node Red - R Pi sensor

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dceejay 2 November 2021 22:58 16

Well it would explain the errors seen. As. python3 /home/pi is not a file it can execute

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Node Red - R Pi sensor

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