Remote Start using Cell Phone: Part 1

Headphone jack plugged in.

Recently I added a remote start to my car.  All is good in the world.  Unfortunately, I work at an airport and my car is about a 15 minute shuttle ride from my office.  There is not much opportunity to ‘stand at the door and wait for warm car’ there.

But cruising the web, I happened upon the Viper website, where I read about a new system where you can start your car via an iPhone from virtually anywhere.  After looking into the system, I soon stumbled onto the fact that the system is ridiculously expensive, as is everything that has to do with the Godforsaken iPhone newer technology.  Further research on the subject yielded little hope, as all other systems were out of my budget (cheap as heck).

My co-worker and I started daydreaming on the subject (what goes on at an airport that we would need to pay attention?) When I stumbled on an idea.  My remote start has a wire called the Remote Start Activation Input.  Now the job of the RSAI is, from the manual:  “This wire will start the vehicle when it sees two negative pulses. Only used when incorporating into existing alarm or FOR TESTING PURPOSES.”  That last part I capped and bolded, as that is what is most important for me.  “Testing” consists of simply grounding that wire for two pulses in order to start the car.  Two more pulses shuts it down, exactly like using the remote.

Bingo, I had my way in!  Here is what I came up with:

Remote Start Using Cell Phone

I know, I suck at diagrams…

I hope you can tell what is going on there.  If not, here is a synopsis, and a little bit of method behind my madness…

The remote start requires 2 pulses within 3? seconds to initiate the remote start sequence.  So how to send those 2 pulses?  Easy, I remove the vibrate motor from a cell phone or pager and use that circuit to initiate the remote start by setting the phone to vibrate.  But wait…the RSAI only works when put to ground, that circuit has (after testing) a 1.35v current. I guess I have to use a relay!  Oh no…The remote start turns off after 2 MORE pulses.  How do I get the cell phone to STOP sending rings?  Hrm…

The answer came from beegbie over at  The remote start start up sequence goes like this.  Sense Input>Turn on Accessories>Try to Crank Engine.  If I put a normally closed relay on the vibrate circuit triggered by the vehicle accessory circuit, then once the remote start sequence kicks off, any subsequent rings by the phone won’t be ‘heard’ by the remote start.


Here are some pictures of the tear down and modification of the cell phone:

Cell phone to be hacked.

Kyocera Jax from Virgin Mobile

Purchased this phone for $10 from CVS Pharmacy along with $20 worth of prepaid minutes.  Phone came with a battery and wall wart charger.

Jax with the back cover removed.

Jax with the back cover removed.

Jax with the inner bezel removed.

With the inner bezel removed.

Removed the 6 tri-wing (fail) screws holding the inner bezel on.  Once off, all the goodies are revealed.  You can remove the PCB fairly easily, but for the most part it is single sided.

Wires soldered to vibrate motor resistors.

All wired up.

Here I have already removed the vibrate motor and soldered wired back into it’s place.  I wanted an easy way to remove the phone if I needed to make any modifications to it or add minutes, or hell, even make an emergency phone call.  I decided on desoldering the headphone jack from and isolating it with that paper stuff I got from another board.  I glued the paper down, then glued the jack to it.  Then I soldered the pins that correlate to the 2nd & 3rd pins on the headphone jack to the wires coming off the vibrate motor resistors.  I chose (had no choice) to solder the wires to the resistors due to me tearing out the traces on the pcb when removing the motor.  I was a little skittish applying the amount of heat required to remove that bish, thinking I might desolder some of the tiny little components around it.  Also of interest to some would be my choice of wire.  That is two strands from a IDE connector.  One is marked to denote it’s polarity.  (It helped, really.)

Picture of the headphone jack.

Headphone jack lookin stock.

Here is a picture of the headphone jack lookin’ all normal and stuff.  I like a nice clean install.  This way the phone loses only the functionality of vibrate and using a headset.  I can still set the ringer, make calls, etc.

Headphone jack plugged in.

Picture of the homemade jack.

Here is the modified headphone jack for the hookup.  This is a 2.5mm (mini) headphone jack that I had from a cheap headset from another phone.  The wires were those damned coated wires, and quite puny at that, so I cut apart the boot and desoldered them at the source.  I then removed 2 wires from a 10ft piece of cat5e and soldered them in place, shrink wrapped and Bob’s yer uncle.  Why, you should ask, did I use Ethernet cable.  Several reasons:  It is sturdy, it was solid not stranded, I could pick my length and I have about 300 feet in a box behind me.

All in all I think the thing may actually work.  I need to source some cheap solid state relays that initiate below 1.5 volts.  I am also thinking about maybe using an optoisolator, as I have 2 in a scavenged pcb beside me that are in the correct voltage range.  I will still need a 30A auto fuse for the other relay, though.  I have a breadboard on order from Sparkfun that should come in handy for testing.

The best part of this project are the possibilities.  Not only can I remote start my car from afar, I can also use the other features of the phone to automate the remote start.  I can set up to 4 alarms on this phone, and set them to vibrate.  Since I work 4×10 shift, that is perfect for starting my car everyday before work.  Also, that phone has a timer on it that can also trigger the vibrate function.  Haven’t figgered out a practical use for that yet.  But the Pièce de résistance is the Calendar.  I can set nearly unlimited events into the calendar, and set an alarm to trigger the vibrate at or before the event in 15 minute intervals.  I can also set the as ‘recurring events’, too. I could program in mine and my wife’s work schedules, upcoming doctors appointments, ANYTHING!  Not bad for a $10 phone.  I am glad that I decided to make the phone easily connect/disconnectable.

Check out Part 2 to see if I can actually pull it off.

185 Responses to “Remote Start using Cell Phone: Part 1”

  1. [...] on Dave Hacks’ cellphone-to-remote-starter conversion project, detailed at his blog (in parts one, two, three). Not for the faint of heart, and not for your brand-new, manual transmission BMW, but [...]

  2. slater182x says:

    Does this work with manual cars? I could really use this with my 97 TDI Jetta. It would sure beat going out in the middle of winter to start the thing and leave it run for 10 minutes while I shiver uncontrollably, and since I leave the defrost on, that would not be a problem either!

    Also, about the phone minutes thing. Wouldn’t there be a way to hook it up with google voice or some other free service like that?? Just a thought, don’t really know the requirements/merits of GV.

    • uh huh says:

      i’m sure it will. the only reason most companies do not install remote start of (TRUE) manual vehicles is due to liability. most people habitually place their 5spd cars into gear when they shut them off…so you can see the issue with adding remote start to a manual vehicle, which is in 1st gear while parked. insurance and possible lawsuits.

  3. khisanthax says:

    after many long hours of reading and researching I finally got it all figure out and … it works great!!

    If anyone is trying to replicate this same idea I’d be happy to explain how I did it as well, although it’s identical to dave’s hack.

    I’d give my email but i’m afraid of spam, lol. it does require a lot of patience and some skill with soldering since rushing will only mess things up. In the end I only had three wires to connect, one for the remote start, one for a 12v acc and one for a ground.

    There was one thing that I added, I bought a mini usb car charger from ebay and connected it to the car as well because i noticed the battery doesn’t last long and now when the remote start turns on or the car is on for any reason the cell phone gets charged automatically.

  4. jig says:

    hey plz. cn u tel me in which other phones this is available….v hve 2 make a project…so cn u plz. guide me for that…reply soon

  5. Roger Fresco says:

    Is this possible to do with any other cdma phones? I sell page plus and their minutes are good for 4 months instead of the traditional 1 month. I can use almost any verizon phone for page plus. Long term it makes more sense to go with that company as their minimum is $10 for 100 minutes, and that should last the 4 months so you would only have to add $30 per year to do it this way. I am certainly concidering this for my truck. Kudos

    • admin says:

      Actually the new version I am working (slowly) on should work on any phone with:

      - Customizable ring tones.
      - Automatic call answering.

      Should be pretty cheap if you have a regular cell account (i.e. Spring, At&t…) that you can add-a-line for $10/month.

  6. TONY says:

    OK, some time has gone by now i the kit available sale yet?

  7. TONY says:


  8. Which remote started did you get? I have looked at a few and not all of them seem to have a “test” option.

  9. Tom H says:

    I would really like to buy this as a kit, and hook it up to my car alarm/starter. It would work quite well.

  10. Boris says:

    Awesome project, but really it can be done with only using simple pager which also eliminates possibility of someone diling the wrong number.

  11. bert says:

    Who knows how to wire GSM to send stored sms to preprogrammed no when receiving a signal say from power loss alarm? I thought of maybe soldering contacts to redial button but was unsuccesfull Do car kit/handsfree kits maybe have wiring available for this?

  12. scott says:

    Hey, im thinking about doing this project for myself. Think you could shoot me an email so we can talk back and forth so I can ask some questions?

    • admin says:

      I am sorry, but I do not want to share an email address at this time. You would be AMAZED at the amount of spam this blog gets.

  13. cityville says:

    hey there nice site and web theme. I hope I am not troubling you I just wished to ask precisely what wordpress plugin you have to display the most recent commentary on your blog? I really want to do something along the same lines for my free apple ipad site but I cannot find the plugin or widget for it. Thank you for your time :)

  14. Bill Meaden says:

    Hello, if i do the phone install, will my regular transmitter still work, having both would be great.

    thanks, Bill

  15. Phoghat says:

    This sounds like a fantastic project. I’m wondering what would have to be done in order for it to be able to shut off the car as well

  16. WILLARD SMITH says:

    My son is 16 and is takinga digital class in high school for his first semaster he had a projec and an idea to biuld a remoat start for a car using text messaging and with a few chips and a sim card holder made it work it is on a proto type bord right now for his second semester project we are installing it in my wife car i use att all i do is pull my sim card out and install it in his device and it works start the car roll up windows lock unlock what ever we want all it needs is cell signal to recive a text

  17. rayr says:

    guess that will work with cruddy 10 dollar phone. But what about a Smartphone that you pay 100 a month for Internet and is currently discontinued. Yeaaaahhhh..DIDNT THINK SO

    • admin says:

      As long as the phone will vibrate, this hack will work. You can use just about anything that has a mechanical output. Cell phone, pager, etc. If I ever get around to working on it, my next version is going to work off the headset jack, and will work with nearly ANY phone. But, thanks for the smartass reply. It was motivational.

  18. franco says:

    hello. can you tell me if i can use remote car strart rs-4 in every cars?? thank you

  19. franco says:

    franco :hello. can you tell me if i can use remote car strart rs-4 in every cars?? thank you

  20. awesum-o says:

    Hello, I am designing a similar system to start my car. Currently I am looking for cheap phone that has the option to have it vibrate from single number, and ring or be silent from the others. Does anyone know of such a phone that has this option. Used and cheap is what I’m looking for.

  21. Al says:

    Damn, that is crazy cool. Nice job.

  22. Sam says:

    Great info. Keep up the good work

  23. puneeth says:

    Great job sir.Please keep updating projects like this.Its informative.Infact I am struck with an idea after seeing this post. can i start an electric motor automatically by making a phone call? please explain and guide me in this.

  24. SLP says:

    So, pretty much you just need to make the phone vibrate to start the car right? I’m new to this field, so I really don’t know what’s what yet. But, most phones will vibrate if you press the volume buttons on the side to turn the volume down to (what else?) vibrate. Would save minutes which seems to be the big F that factor. Same as calling the number? Or does turning the volume down to vibrate eliminate a needed pulse that you talked about?

  25. SLP says:

    I got excited and didnt realize I forgot to read parts 2 and 3. Sorry man.

  26. Don says:

    hi Dave,

    i have been thinking about doing this mod for awhile now and i had it figured out in my head except for the second relay needed to shut down the cell phone so thanks for the idea of adding the second relay. im going to install on my remote starter very soon. also i was thinking that if you had a light sensing or sound activated relay you could use them without having to modify the cell phone at all what do you think about that?
    p.s. i also work at an airport and hate to have to be near my car to remote start it and thats why i need this mod also, thanks!

  27. i hope i can need it in my thesis and can u give me some
    schematic diagram bout this system.
    tnx hope u help me =)

  28. i hope i can use it in my thesis im an I.T student. will u give my some schematic diagram about this system. we have proposed thesis as AUTOMOBILE CONTROLLER SYSTEM FOR CAR/MOTORCYCLE by using a mobile phone in controlling this system. like on/off engine,horn,light and alarm system by sending a SMS command. the problem is we don’t know how to connect cars a receiver for the text command.hope you can help me thanks.=)

  29. [...] on our theme of cellular hackery, Dave has a three part series on his blog dedicated to the creation of a remote start system for his car. What’s the catch, [...]

  30. Mr. di says:

    Well it seems a bit complicated, I suppose that the more reliable and convinient way is to install the car alarm system that already supports cellular control of the vehicle, for example Viper 5902

  31. I actually did exactly that. It works fantastic. Well, worked, lol. Using solid UTP cable was not the best as the vibration in the car made it break off. I need to re-do the connector to the project box with stranded cable. Link to your project if you get it done!
    Have you thought about just using the alarm function of the cell phone? That way you don’t have to keep paying for the cell phone minutes. I’m thinking of using my old T-Mobile Nokia RH121 to turn on an irrigation system for my greenhouse.

  32. Mainly needed to submit and question where you bought your layout? I’m shopping around for one for my current blogging site and really like yours. Thanks.

  33. [...] done this already but using the power wires from the vibration motor to trigger the start signal. Remote Start using Cell Phone: Part 1 | Dave Hacks See link above. I currently have an apache phone I was looking at doing this with but am planning [...]

  34. MOE says:

    I got a few questions, the Activation input is only used for another source of turning on your car? Such as what you did by using the cell phone? Can I not use the activation wire if I am using the remote key that came with the starter? Also what if someone dials your cell phone numbers by accident (Not Friend or Family) just wrong number? Isn’t that dangerous or you have a way around that as well. Thanks.

    • admin says:

      Would not be dangerous unless you were napping in your car in your garage when they called. The car cannot be shutoff with a remote start once the key is inserted, it’s a built in safety to prevent someone (kids) from fooling with the remote and killing the engine at 65mph on the freeway!

  35. Matt says:

    Just curious, couldnt you have just hooked up the headphone jack to your rig without all the desoldering/resoldering. The phone would ring thru the headphones correct? Or am I missing something?

  36. @Meredithrpb says:

    Thanks. This is actually a good read.

  37. Léovine says:

    le boin coin is a good process.

  38. [...] There are hacks floating around where you can do the same thing with a cheap cellphone. Here’s Dave Hacks for how to start your car remotely with a $10 disposable cell phone. But the only thing you are [...]

  39. [...] bit of circuitry knowhow and Dave Hacks could help you turn that old cellphone (with a few calling minutes) into a cheap remote start for [...]

  40. Oh my goodness! an amazing article dude. Thanks However I am experiencing issue with ur rss . Don’t know why Unable to subscribe to it. Is there anyone getting equivalent rss problem? Anyone who knows kindly respond. Thnkx

  41. Elia Leneave says:

    I gotta favorite this internet site it seems extremely beneficial .

  42. Chris says:

    Yes sir, I do approve.
    I stumbled across this looking for something else related to this.
    The manual states that this wire can be programmed to one pulse. Not sure how though.

  43. joeyboy says:

    i have myphone t28tv duo the problem is totaly grounded how to make remove this problem pls help.

  44. [...] out pics, a diagram and project info on his Dave Hacks [...]

  45. stilltrying says:

    I found this page trying to locate the service manual for the same phone — nice hack — would you send me the link for the service manual.

  46. [...] Remote Start using Cell Phone: Part 1 | Dave Hacks Jan 8, 2010 … But cruising the web, I happened upon the Viper website, where I read about a new system where you can start your car via an iPhone from … [...]

  47. tom says:

    I would like to be able to turn on my 12 volt furnace at my island cabin which has only dc power. I have a wifi hot spot out there and a basic 12 volt thermostat (rv type) . I thought maybe I could put a switch in line that I could activate with my cell phone??
    Any ideas?

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