In this quick Arduino tutorial I will explain how you can control a relay using the Arduino Board, one 1K and one 10K resistors, 1 BC547 transistor, one 6V or 12V relay, one 1N4007 diode and a 12V fan ...

The relay can be used to open a door lock and if you need a louder alarm then you can replace the small buzzer with a high power siren. I will not talk about the RFID reader because you can find a lot ...

The Arduino sketch is also setup to give “hints” to the player ... as a quick demonstration of how both the RFID “combination” and manual override can be used to trigger the attached relay.

Using MegunoLink Pro, the min/max temperature points can also be set without uploading a new sketch to the Arduino. From the temp vs time graph, it looks like the room temperature stays a ...