This morning I started testing the YL-03 solenoid lock, using 12V 1A SMPS, and a manual power switch to switch on/off 12V power to the lock. Everything went smoothly: (a) power on, tongue retracted into body, lock unlocked, (b) power off, tongue returned to normal position (locked). So far so good, next step is to add a mosfet IRL540N to switch on/off 12V on/off power to YL-03.

I have tested the Solenoid locks and it works perfectly with the Raspberry and the RFID @tlfong01

@AhtishamAshraf So I have test the 12V 1A PSU direct connect to YL-03 and use manual High Side Switch to power on/off YL-03 OK. Next is to use the IRL540N MOSFET as low side switch to switch on/off YL03. (The high side switch is still used).

The test circuit schematic is v0.4, and uploaded to Appendix H.

@AhtishamAshraf Ha, that is very good news. Do you mean that your program can now not only live once, twice, but many more times?

Yes for the Solenoid lock but not for the magnetic door , i am still digging deeper @tlfong01

@AhtishamAshraf I have also tested my 60kg magnetic door lock, by directly applying 12VDC across the lock, with flyback diode across the psu (so also across the lock). The lock attract the megnetic bard very tightly, and release the bar when power off. This is what I expected. But one thing not expected is this: There is a white push button on the top of the bar.

I wrongly thought that if the lock and bard attracted/stuck/locked together, and I push the white button, then they should somehow demagneticized and lose attraction. But this does not happen. So I have the following question:

Question. What is the use of the little white button on the top of the iron bar?