remote start via disposable cell

I did a few searches for this, but was unable to find anything on my specific needs.

I am not searching for a commercial solution, but rather a DIY solution to remote starting my car via cell phone.  The theorized method behind my madness is to use a prepaid cell phone to trigger the remote start via the Remote Start Activation Input on my remote start module.  My understanding is that this wire needs to be put to ground the prescribed number of times (same as the number of times the key fob is pressed) to start the vehicle.

My theory is that I can crack open the prepaid phone, disconnect the vibrate motor and use this portion of the circuit to bring the Remote Start Activation Input to ground.  Problem is the predetermined number of pulses to activate the start sequence, as the vibrate function is undetermined.  If the phone has a "vibrate once" function, then I'm golden.  If not, I'm in for more tinkering.  Some solutions I an thinking of are these:

-Use the phone vibrate function to trigger a relay.  (Still fail if the relay just continues to trigger with each vibrate)

-Use a 555 timer to intercept the vibrate signals and trigger a relay. (Don't know much more about a 555 timer other than what it does.  May not be able to do this.)

I hope there are some people out there smarter than me who can help me figure out if this will be feasable or not.  Any and all help is appreciated, or just general feedback.  Thank you in advance for your help, and thank you for the great forums.  I'm glad I found you!

I mod stuff...yeah...

http://www.viper.com/smartstart/ I just installed this in my car last night and it is really cool. Much more expensive that what your going for but it may be worth it for all the added features. Iphone is the only phone supported now but it will be coming out soon for blackberry and droid phones.

Just had another idea. If you can successfully get a output from the vibrate buzzer from the phone, set the remote start for two pulse activation then add a relay triggered by ground while running to split the activation wire, that way once the remote start is activated it will ignore any additional pulses from the phone. Good luck.

Depends on what kind of remote starter you have, and how it's programmed. Some units require multiple pulses, some require a single pulse, and some can be selected by programming. In any case, your idea sounds like a good one. You might want to look into pulse timer relays like the DEI 528T or PAC TR-7. Not sure if they might help your project or not but worth looking at. You could probably set up the timer relay to either ignore or create double-pulses as needed.

beegbie wrote: http://www.viper.com/smartstart/

Thank you for the information, but I am fully aware of that system and I am not currently interested in any commercial products.  This is for my work car and is not really NEEDED, but more of a "lets see if I can pull this off" project.

beegbie wrote: Just had another idea. If you can successfully get a output from the vibrate buzzer from the phone, set the remote start for two pulse activation then add a relay triggered by ground while running to split the activation wire, that way once the remote start is activated it will ignore any additional pulses from the phone. Good luck

Not sure if I understand 100% of what you are getting at here, but from what I gather you want me to hook up a relay that will open the circuit when the ingnition current is active so that the remote start will not sense any more pulese from the cell phone?  If so, there are a few problems with that, although it is a promising step towards a solution.

-The remote start has about a 5 second delay from the time the pulses are sensed until it kicks over the starter.  It does, however, turn on the ACCESSORIES during this time, so I may be able to splice into the acessory output grid to open this relay.  That, however, brings us to the next problem....

-Cold Weather, Old Car:  My auto is 12 years old and doesn't always start the first time, especially in cold weather.  If there is no initial start, then it waits 15 seconds and tries again, then 30, then 50.  If the accessories remain on during this time, then your idea has incredible merit; however I need to see if this is what actually happens.  If it turns the accessories off between cycles, then we are screwed.  I do, however, believe that it leaves the accessories on as the manual said something about priming the fuel system between cranks; so we'll see.

Chris Luongo wrote: Depends on what kind of remote starter you have, and how it's programmed. Some units require multiple pulses, some require a single pulse, and some can be selected by programming. In any case, your idea sounds like a good one. You might want to look into pulse timer relays like the DEI 528T or PAC TR-7. Not sure if they might help your project or not but worth looking at. You could probably set up the timer relay to either ignore or create double-pulses as needed

My remote starter is a Directed Electronics "Cheap as hell but works" brand.  Don't have the model # in front of me right now.  I can program my remote start to use 1, 2 or 3 pulses; as it has the flexibility to let one remote start many vehicles with different inputs. 

I don't know what a pulse timer relay, but it the name fits what I need exactly!  I wil definitely Google that and do more research.

All in all, you guys have already put down some solid solutions.  Thank you!  Now all I have to do is wait until it is not 22 degress (F) where I am at and I will get some wiring done.

I mod stuff...yeah...

"Not sure if I understand 100% of what you are getting at here, but from what I gather you want me to hook up a relay that will open the circuit when the ingnition current is active so that the remote start will not sense any more pulese from the cell phone? If so, there are a few problems with that, although it is a promising step towards a solution. -The remote start has about a 5 second delay from the time the pulses are sensed until it kicks over the starter. It does, however, turn on the ACCESSORIES during this time, so I may be able to splice into the acessory output grid to open this relay. That, however, brings us to the next problem...." This is why I told you to use ground while running dei calls it the status output(blue w/white wire). It comes on immediately when the start gets triggered and stays on until the car shuts off. As far as the car not starting, I'm sure that by the time it tries to start again the phone will have stopped ringing by then. That and you should hook up the tach input so the remote start will crank for as long as it needs to start the car. Even a 12 year old car should not take 3-4 tries to start unless there is something wrong with it.

We sell Titan systems and they have a basic start, unlock & starter disable system available. The TT100 is the one that your wanting and it can accept a single or a double pulse to remote start.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

beegbie wrote: This is why I told you to use ground while running dei calls it the status output(blue w/white wire). It comes on immediately when the start gets triggered and stays on until the car shuts off. As far as the car not starting, I'm sure that by the time it tries to start again the phone will have stopped ringing by then. That and you should hook up the tach input so the remote start will crank for as long as it needs to start the car. Even a 12 year old car should not take 3-4 tries to start unless there is something wrong with it.

Actually, I think I am going to use a setup pretty close to what you put out, but instead use a DPDT relay and use the Accessory current to cut the cell signal.  Everything else you are right on with.  I am just waiting for my relays to come in on order, as I need 1.0v triggered relays as the phone current is way low.  I will post a crude drawing of what I am going to try here in a few.

Thank you beegbie for all your help, and to everyone else that posted up!

I mod stuff...yeah...

This is a crude diagram of what I am going to accomplish.  The voltage coming from the phone is going to be 1.3 - 1.5v, and very low amperage.  The Remote Start Sense only puts out 0.6v according to some documentation that I found online, si don't think I need any resistors or diodes or anything.  If anyone smarter than me (which is most people on here) can think of anything I need to add to this circuit for convenience, safety, etc.; please let me know.

Also, so I can access the phone easier; I plan to remove the surface mount earphone jack, insulate it from the board and re-glue it down.  Then I will solder the two trigger wires into the jack.  That way I can "plug in" the phone and use it to remote start, or I can remove it to work with the menus or charge it with minutes.

Here is the diagram, sans the headphone plug.

I mod stuff...yeah...

Why not use a remote? If you are trying to start the vehicle when you are out of state or the country, or when the possessor isn't aware of it, then I understand your application. Just make sure you keep the number secret, and don't vibrate on SMS (we get civil emergency SMSs etc here, and several wrong numbers!).