Better way to run Python continiously or limit CPU usage

Question

I´m running a raspberry pi4 as an attendance tool. The Pi itself is bored with the Tasks running on it which is basically a nodejs Server a Web Frontend aswell as a Postgres DB.

However if I start my Python Script to check constantly for RFID Tags the CPU rises to 30% usage with one core maxed out which leads to a Temperature increase.

Since all other tasks are basically a no brainer for the PI I was wondering if there is any way to throttle this process down or a better approach for the python script.

The script itself is absolutely basic but unfortunately needs to run in an endless loop like:

reader = SimpleMFRC522()
while true:
        id, text = reader.read()
        if(id):
              ...processData

I´m aware that 30% CPU usage is also pretty much nothing but since the PI does not have any FANs or Heatsinks on it I´ma little concerned about the Temperature in productive env.

Also, since this task does basically nothing but check for rfid tags and if found post data to a restapi, I´m feeling like it´sa waste on used performance overall.

Thanks!

Answer 1

If this is the library, it looks like it's a non-blocking read: https://github.com/pimylifeup/MFRC522-python/blob/52d5a6952c70c97a834593fc8092fa9d40c87a2e/mfrc522/SimpleMFRC522.py#L16

Answer 2

You want your read call to block; sadly, the very... thin "simple" wrapper you're using explicitly does a non-blocking read. So, simply replace SimpleMFRC522 with an MFRC522 object and read blockingly.