Demonstrate RFID card matching and a model barrier, while recognizing that card UIDs are cloneable and unsuitable as the only security credential.
Map values one through six onto seven LEDs and use a game-quality pseudo-random seed, not this method for security or gambling.
Reply to an authorized SMS request with a DHT22 reading while powering SIM800L from a low-impedance 4 V-class supply and checking local 2G availability.
Plot several slow, low-voltage analog signals through Serial Plotter as an educational waveform viewer, not as a protected oscilloscope.