12v Trigger? Newbie here.

Hello, this is my first experimentation after doing blinkie.

I purchased a RFID reader from ebay a while back, it was $10 and came with 2 rfids and does not require a computer.

I have played wired it up to an led and have played with it getting it to turn on when the right rfid is shown. Basically if I show the right card, the led lights up, when I take the card down, it immediately shuts off, so there is no relay.

Can I hook this into Arduino? It is a 12v signal that comes out of the rfid.

Meaning, can I have this 12v signal, trigger arduino to do something like turn a servo or power an led?

Thank you,

Scott

Yes, you can. Put a potential divider circuit to step down the 12V trigger to 5V or lesser and give it to an arduino...

Thats great news! Awesome! Thank you for the response.

Any idea where I would look to figure out which resistors I should use in the potential?

12V to R1 to R2 to ground.
Junction R1/R2 to arduino.

Vout = Vin * R2/(R1+R2)

Have R1 + R2 = ~20K
So R2=8.2K, R1=12K would get you in a workable range.

Wow, thank you thank you.

I am not that good at math so you just saved me. I will try this this weekend.

Thank you.

Well look at that. I was actually able to pull off part 1 of my project. My RFID keyless entry to my apartment without modifying the door, lock, or striker (I'm not allowed too) is now installed and working beautifully.

I just wanted to say thanks to those who helped me below. I wanted to quit and now that I see progress I am actually ordering another arduino to try more projects.

YouTube video: Arduino Project - Keyless Entry RFID (Part 1) - YouTube

Nice! Good camera work too. Clever use of a clamp.
Glad to see you're not breaking into someone else's apartment!