@AhtishamAshraf Now that I have separately tests the following subsystems: (1) YL-03 12V 350mA Solenoid Door Lock, (2) IRL540N N-channel Power MOSFET, (3) EL817C Optocoupler, (4) Square Wave Sig Gen JY-108. Now I am doing the system integration test: (a) YL-03 door lock + IRL540N + JY-108 sig gen. I have made a youtube:

It is working okay with the Solenoid lock , the raspberry , can you try with Raspberry + RFID @tlfong01

@AhtishamAshraf Ah, I am troubleshooting your RFID-can-only-live-once problem bottom up: (1) 12V 1A PSU, (2) 12V 350mA solenoid door lock, (3) IRL540N mosfet switch, (4) EL817C optocoupler to convert 3V3 to 5V0 signals, (5) JD-vcc relay, (6) Square wave sign gen (using 0.5Hz to lock/unlock) .

I can do different configuration of system integration using the above 6 subsystems. Actually I have not used Rpi or RFID yet. So far are only off line testing. Next step is to perhaps try, instead of Rpi RFID, just Rpi print something repeatedly . My aim is first make sure that solenoid door switching on/of would disturb even Rpi repeated printing text such as "abc" etc. If even printing something can only live once, then there is no point trying RFID.

And before trying out python SimpleMfrc52 RFID I need to do one thing: Replace SPIpy by Rpi Thonny python built in SPI. Some two years ago I found using SPIpy for RFID and other programs using standard SPI at the same time messed things up. So I hope you can help replacing SPIpy by standard Rpi Thonny SPI.

I have tried debugging the python code but there is no issue in that one as per me @tlfong01