RFID and Arduino in Car.

Alright so I want to put an RFID unlock feature in my old car. Just as something to show off and give me something to work on

I would like to be able to touch a the Sail on Driver side of a Pontiac fiero and have an RFID antenna read a chipped ring on my hand. Would I use 1 antenna or more than one? o

Would It go like this?:
1.Is RFID Tag present? If yes, 2 If no, 1
2. Turn On Green LED Light Strip
3. Move Motor to Position 2 (Lock Pos1, Unlock Pos2)
4.End

also how should I do this without having the antennas constantly looking and draining my battery?

How much power does it take to do one 'look' with the RFID Arduino?

How many amp-hours are in your car battery?

Slow it down so it only looks once per second or something, which will make the battery last a reasonable amount of time.

Could you think Of a better way of doing this? Maybe using a low power peoximity sensor to activate the look circuit? I feel like this would be more power efficient though Im not sure, any ideas?

Proximity sensor has ts own challenges false triggering etc…
One year standby easily with car battery with small code changes.

Ex.

    // Look for new cards low power consumption MCU and PCD
    LowPower_IsNewCardPresent();

    // Select one of the cards
    if ( ! mfrc522.PICC_ReadCardSerial())
        return;

SteveP76:
Proximity sensor has ts own challenges false triggering etc..
One year standby easily with car battery with small code changes.

Ex.

    // Look for new cards low power consumption MCU and PCD

LowPower_IsNewCardPresent();

// Select one of the cards
    if ( ! mfrc522.PICC_ReadCardSerial())
        return;

So this is for the antenna, Will the arduino and antenna drain my battery if left for 1 week? alone without any interaction?

Yes it will drain your battery by a very very small amount negligible. Setup hardware Arduino mini pro 3.3v (power led desoldered) and rc522 (power led desoldered here too if any).
Sleep current arduino mini pro + rc522 = 60uA current consumption is very low because
power on card detection is in the milliseconds range. 4 AA alkaline in series will last 25 weeks for sure field test.
A car battery should out perform that easy and be able too start car.