How to start your car from a cell phone via GSM relay!

In this instructable I will show you how to start your car from your cell phone.  I already had a car starter installed in my truck years ago but the range was terrible and you had to press the button for a precise amount of time, otherwise it would just ignore it.  So instead of pressing a button all day long from 10 feet away I decided I wanted to start my truck from anywhere in the world!

Step 1 What do you need?

Parts:

-GSM activated relay.  This device will contain a SIM chip that can connect to the GSM cell phone network.  It's relays must be able to be activated by phone call or text message.  In my first build I used a GSM-AUTO, but found a cheaper alternative on eBay HERE for the Quad Band version (North America) or HERE for the Dual Band (Europe, Asia, etc.). it costs around $150 which has 7 relays.  One relay is controlled by phone call and the rest are activated by text message.  The relays can be set as either momentary or latched.
-Car Starter Key Fob (the remote control thing on your keychain).
-12V DC cigarette power cord
-Small plastic bag or ESD bag.
-A few wires.

Tools:

-A few screw drivers
-Soldering Iron

Comments

[thakur900]

I was thinking that would it not be possible to use this gsm relay for home automation? that would be really cool! can u give some suggestions??

[Tetragammatron]

Yes, you can use it for home automation quite easily! I have a friend who has his wired to his thermostat in his cabin. He visits about once a month, so he keeps the place very cool. When he leaves the city to drive to his cabin, he text messages the device to turn on, and it activates the furnace, warming the house up for him for when he arrives so he doesn't have to wait around while the place warms up. The unit texts back confirming the state that the relay has entered (on or off) so that there are no mix ups.

Same goes for a water heater (wired into the control box of the tank).

I'm planning on installing an RFID activated electronically controlled door to my home, and I'll likely add one of these so I can remotely open the door if someone needs to get into my house, or I don't have my RFID tag with me. Since it has a white list of phone numbers that are allowed, it would be secure. Another use would be for a garage door or gate opener.

The one I used above can only be powered by 12V DC, but there are units that can be powered by 110V AC or 220/240V AC as well. These ones also have inputs so they text message you when the inputs get grounded. You could use this as a sort of alarm system, or could attach it to some kind of sensor (door sensor, infrared sensor, etc):

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&rd=1&item=200536597466
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&rd=1&item=200545392665

[triscuits]

Wouldn't you need a voltage regulator on the key fob itself to prevent a surge of current or voltage from the vehicles battery? The voltage can range wildly depending on whether the truck is running or not.

[Tetragammatron]

The battery is a 12V 23A battery, so the current shouldn't be an issue from the battery. The voltage was a concern. I checked with a multimeter on my truck and it ranged from as low as 8V up to 15V.

A voltage regulator is a good idea (its the proper way) but I was a bit lazy and didn't bother. I've been using it for over a year and have had no problems, but tossing in something to regulate the voltage to 12 volts would be a nice addition.