interfacing Arduino to Power locks

[Kamatari+]

Hello all! I'm working on a project where my Arduino (Duemilanove board) can connect to and control the power locks on my 91 EX. I'm following this guide where the user used an arduino to be the middle man between an RFID reader and the operation of the power locks. I merely want to control the locks from the arduino to prototype some other projects, without the use of an RFID reader.

I'm waiting on some N-Channel MOSFETs' and 10K resistors.

My plan was to connect the arduino to the power lock switch on either the driver or passenger side, since the switch only has three wires:

Green/white  =  lock
Green/red.   = unlock
Black.       = ground

And send the appropriate voltage to either circuit to lock or unlock the doors. Since I'm only focused on doing step 1 of this instructable is there anything you would suggest, Any thing I might be missing, or any general help you could offer? Thanks !

Update 1 : Wired up and working
Update 2 : Going with bluetooth
Update 3 : parts arrived, wired up and tested

[sonikaccord]

Or you could have it trigger the way the OEM security does. There is a blue connector taped in the driver's kick area. If you apply GND to one of the two wires it will either lock or unlock the doors depending on which one is triggered.

Also our locks are a negative/GND triggered circuit. If you apply 12V it may not work or damage the circuit. So pretty much, [trigger wire]> Source and Drain>[Ground]

[Kamatari+]

Or you could have it trigger the way the OEM security does. There is a blue connector taped in the driver's kick area. If you apply GND to one of the two wires it will either lock or unlock the doors depending on which one is triggered.

Also our locks are a negative/GND triggered circuit. If you apply 12V it may not work or damage the circuit. So pretty much, [trigger wire]> Source and Drain>[Ground]

I don't have OEM security, would the connector still be there? I'll look for it when I get to my car later today. Thanks for the correction! I did in-fact mean applying ground to either the lock or unlock wire, I shouldn't have said apply 12V. . When you say source and drain, are you referring to the MOSFET? This is my first time using such a component. I am using this : RFP30N06LE and following the schematics he posted, such as this : (step 1)

Edit:
This is how I currently understand the circuit. Is this correct?

[sonikaccord]

That's it. Yes all usdm cb7's came with this optional harness afaik. I used mine when I installed my aftermarket alarm.

[Kamatari+]

I hate to be a burden, but where is the driver kick area? I'm not fully up to par . Thanks again!

[sonikaccord]

Lol, it's cool.

The interior fuse panel area, where you rest your left foot. You'll have to take the plastic fuse panel cover off.

[Kamatari+]

I looked in the kick panel for a blue connector but didn't see one. I was using my phone as a flash light,
had limited head room, and was upside down so I might have missed it.

[sonikaccord]

It's in the main loom under the fuse box, wrapped in electrical tape. I'll see if I can find a pic.

Found a thread, it's a grey connector wrapped in blue tape
http://www.cb7tuner.com/vbb/showthread.php?t=192267

[Kamatari+]

Ah alright thank you! So it's under the carpet near the kick panel. How would I go about applying ground to this two wire connector?

Black/red    =  unlock
black/white =   lock

The harness connected directly to the power lock switch has a ground wire. Do I use that wire or ground this connection to the chassis?

[sonikaccord]

The ground wire is connected to chassis, so use the one that is easier for you to work with.

I chopped the connector off. You could crimp a bullet connector or spades. Or solder it directly.

[accordztech]

25 seconds, what a waste of time.

Get an alarm.

[cp[mike]]

25 seconds, what a waste of time.

Get an alarm.

the dude said he wrote that part into the code intentionally, because it "works better for me." not quite following that logic or why he would do it that way.

[sonikaccord]

My 8th gen does that...if you press the unlock button and don't open the door withing 30 seconds, it locks again.

RFID can be sensitive. If you lock the door, then happen to brush by the door with your key, your door could be unlocked the whole time while you are sleep, watching a football game etc.

Plus, let him learn how to program. It's much better in the long run vs buying an off-the-shelf solution.

[Kamatari+]

Just wanted to post my progress

I received my MOSFETS in the mail yesterday and got to work. I copied the plans to the letter and it worked for me. I still went with interfacing the arduino to the master power lock switch line, because I don't actually have a switch plugged in there. I powered the arduino by plugging it in to the cigarette lighter.





In the second image, the red wire is plugged into the Green/White wire.

Here's the code I wrote up really quickly, with commentary.

/*
  
*/
 

// the setup routine runs once when you press reset:
void setup() {                
  
  pinMode(4,OUTPUT);  // Unlock pulse         
  pinMode(5, OUTPUT); // Lock   pulse
  digitalWrite(4,LOW);   //Unlock stop
  digitalWrite(5,LOW);   //Lock   stop
  
    
}

// the loop routine runs over and over again forever:
void loop() {
 
  digitalWrite(4,HIGH);   //Send pulse to unlock door
  delay(1000);
  digitalWrite(4,LOW);    //Stop unlock pulse
  
  delay(5000);            // Wait 5 seconds
  
  digitalWrite(5,HIGH);   //Send pulse to lock door
  delay(1000);
  digitalWrite(5,LOW);    //Stop lock pulse
  
  delay(2000);             // Wait 2 seconds

  
  
}

And basically where I am currently at is my Arduino will unlock the car doors, wait 5 seconds and lock the car doors, wait 2 seconds and start over. This is all very rudimentary, but I wanted to show it can be done. The possibilities are endless since the Arduino is capable of so much. As of right now I do not have any shields or interfaces, so I'm limited to just the arduino. My next step is to control the Arduino via serial input, so I can type from my laptop "lock" or "unlock" and have the Arduino accept that as a valid command.

Thank you so much for the help sonikaccord!

[Kamatari+]

25 seconds, what a waste of time.
Get an alarm.

With that attitude, I suppose Benz should have stopped making cars in 1888.

"A vehicle that can only travel of 2/3 the power of a horse, might as well just get a horse!"

The Arduino acts as a middle man between what ever interface you could imagine: Bluetooth, RFID, WI-FI, Proximity, secret knock, voice command... whatever and more. The purpose of this project is far from being a top notch security system. Most alarms use RF. You are stuck using RF as your internment. That's great if you only want a simple and fast way to unlock your car remotely. Really, this is hardly a waste of time you!