RFID Controlled Car Trunk

Step 6: Installing the System

This is where is really gets complicated. You will most likely not be installing your system onto a 2003 Mazda Protege, so you are going to have to get creative. 

Key points to remember when installing system:
 - Install the reader close to the surface of the car (less resistance = more range)
 * Install the reader where the radio waves will not have to travel through metal!! (This is a low power system, if the waves have to travel through metal, they lose their energy and effectively block the communication between the tag and the reader) 
 - Use lots of wire, its better to have extra than to realize half way through the install that you need to solder on more wire
 - Cover the reader with many, many, zip-lock bags and cover the entire system with waterproof electrical tape, make sure the tape extends to the wire (don't want a short causing a fire...)
 - As for installing the servo: My car's trunk is not furnished and there is an accessible cord that pops the trunk. I attached the servo to this cord, when it rotates, it pulls the cord. There are convenient holes that I used for mounting the system. I used some flat metal pieces and nuts and bolts to attach the servo to the car, so far this has worked great. 
 - Put the system in a box ( doesn't have to be fancy) to protect the electronics from unnecessary crushing 
 - Try to be neat and not do damage to the car (I hope this one is obvious) 

Comments

[WABIX]

I have a pro micro and I never solder my FTDI headers into it. Instead, I stick the long end of a 6 pin straight header into the USB - FTDI. Then stick the short end into the 6 holes on the pro micro while programming. When finished, all you have to do is remove the header + FTDI. If you are doing small projects, this can save a lot of space.

[Hycro]

With my car I could just run a power wire from the car battery to a relay triggered by the Arduino, since with my car the interior trunk release is electric...

[duggerpato]

So tell me about the servo, before I buy one (for a different idea), since I don't know anyone who messes with servos. Does it just rotate that wheel like 90 degrees, and return it to "0"? Could I program it to rotate 90 degrees, and stop until I want it to return to 0? I want something that could open a spring with an electronic signal, then return it when I want it to afterwards. Am I on the right track here? Great instructable, btw.

[Untold]

Hi, servos are used with Arduino on lots of robot projects such as this one, where you can find sample code using the servo library:

http://www.instructables.com/id/Simple-Walker-Robot/step25/Program/

There may be better examples than this, but you can get an idea.  I am building this as my first robot project and I found it very easy to drive the servo to any position within its range (easily 90 degrees or more) and hold it there. For this 'ible, if the cord is stiff to pull, you might need a very strong servo though. I am not sure the average hobby servo will be strong enough - This depends a lot on the car.  Good luck with your project!

[duke2luke]

I agree with Untold's comment. The code is simple if you use a limited rotational servo. If you use a unlimited rotational servo it will be harder to code because it will use pulses to detect its position.
As for the strength of the servo, Untold is again correct. I started with a smaller servo but needed to upgrade to the one I listed.
Good luck on your project duggerpato!