When everything is running and powered on, you take the rfid card and scan it on the rfid reader. The lock is automaticly open and upon card scanning, the lock will close. when you meanwhile try to scan with another badge, this will not work because it is another than the one that last checked in to store his bike.
When you scan with the card again that was used the first time, the lock will open again, and you are free to take your bike back home.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.