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Cheap Simple Pre-Loaded Sim Card? Answered

So I am looking at making some GPS/GSM trackers which are attached to a vehicle and then used in the case of theft.  They would be powered by the car's electrical and would also have a separate backup battery in case the thieves were smart and disconnected the electronics.  The only problem I have seen in planning is the requirement for a sim card on GSM modules.  I understand that I will be required to pay for service, but I need long range, maybe even international service which can send maybe 20 text messages at most.  A pay as you go would be reasonable too.  I just don't want to pay a monthly fee for a fake phone which just sits on a car doing nothing most of the time and doesn't actually do anything until it is called or texted.  Any car trackers I have found don't offer wireless capabilities and I really think my device would be useful.  


After taking one out of my wifes car and researching it your better off buying one. You can get a whole module for about $200 with a pay as you go plan for the service (tracking/disabling). Used car dealers use them for collection purposes, its a $200 insurance for guaranteed return on the vehicle when you default on a payment.

Why would you need something with international rates? Do you plan on traveling outside the united states to retrieve it? Shipping a car overseas would probably not be economical for theves.

If someone steals your car, more than likely they are going to strip it for parts. Plus if they park it in a parking garage the GPS may not broadcast, and if thats inner city, the GSM may not work either.

Driving into mexico is economical for thieves, its a common occurrence. I just can't understand why everyone is pushing to use a manufactured device on a DIY site, it surely isn't any cheaper to do that, it would cost roughly 100 dollars to make the device I want, if it even costs that much. I can restrict usage and not pay for a plan I don't use, I could have it send 4 locations every minute for better tracking, but I don't have to pay for things like knowing my car is still in the garage all day while I watch TV, I start tracking it only upon discovering it is stolen.

The device i pulled out of my wifes car had a GSM module, a lithium ion battery (for when car battery is not there), a Relay for the ignition, GPS, and was controlled by ATmega chip. You could probably build one for around $100 and spend a few hours coding it.

If someone drove your stolen car into Mexico you might just be better collecting the insurance instead of dealing with the Cartel. : |

This is a little old but tracfone offers cost effective sim card plans for these projects. 1 Year with 400 texts or 400MB of data is $100. You can add more texts or data if needed. and every card ads 30-90 days of service.

Without knowing where you are, the best advice I can give is to go talk to your local mobile phone stores. In the UK, you can buy pre-paid SIM cards for most networks for as little as £10 for a pay-as-you-go card.

Oh, I do apologize, Colorado, USA

AFAIK, similar deals are available in the US.

There are literally hundreds of real time GPS car trackers. They report the car's position, direction and speed in real time and can be monitored from any internet connect phone, tablet or PC. They do require a monthly service plan of about $30. Many offer options to only activate and start monitoring when needed. Most are reginal but can offer international service. The key words to search for are 'Real Time GPS tracker'.

and they also cost well over 100 dollars to make, I don't like paying for things I never use, I don't need real time tracking, I need 1 dollars worth of minutes which last for a while

Any DIY solution you come up with will cost upwards of $100 or more for the device alone. The Real time tracking systems actually sell the hardware for less than it cost them to have it made since they make there money in the service fees. Just like cell phone providers. Printer makers do the same thing. The printer cost less than they cost to build cause they make there money in the ink.

(Often overpriced) Sparkfun has GPS and GSM for about 50 dollars each. I have found much lower priced ones around on the web. I can then pick up an unofficial arduino for under twenty. A box for it is scrap to me and mounting is something I can do myself as well. I don't know where you got your numbers but the "best" real time trackers cost well over that and I have yet to find one for under 200 and then of course you have to include the plan cost.