Roll Your Own LoJack Clone


If you’ve ever worried about your car getting stolen this hack can help give you some piece of mind. It’s a cellular enabled geolocation device. These things have been in use for some time, the most common brand we know of is the LoJack. That company gives you a little box to install on the vehicle and if it ever goes missing they can grab the coordinates and forward them to theĀ authorities. This custom version builds a lot into an addon board for an EFM32 board.

The image above shows the main components of the add-on: the GPS module and the GSM modem. Along the top edge of the board is the voltage regulator circuits which aim to keep the standby power to the slightest of trickles so as not to drain the car’s battery. What you can’t see is the SIM card slot which is located on the underside.

You can find the Eagle files for the design at the link above. We’ve embedded the video description of the project after the break.

34 thoughts on “Roll Your Own LoJack Clone

    1. OK, so LoJack devices transmit RF chirps when activated. But how does the company “activate” the LoJack device and tell it to start transmitting in the first place?

      It’s not clear at all.

      1. They have their own network of towers that send the activation signal, but local LEO have to have the LoJack “tracking” radio receivers in their cars to pick up the transponder’s signal because it’s relatively weak. The system is flawed, IMO, because it depends on them having a piece of third party equipment in their car and it can’t tell you where it is, just the general direction the transponder signal originated from.

        I like the cellular systems better because they allow specific location tracking and don’t require the owner or LEO’s to be anywhere near the object being tracked.

  1. It just occurred to me, you could have your car send a message by WiFi, whenever it is in the vicinity of a free WiFi. So, if the car thief makes the mistake of stopping at McDonald’s, you’ve got the location!

      1. doesn’t mc Donald’s use captive portals? if so doesn’t that complicate the matter?

        i have been using old cell phones running gps loggers for similar activities for a while now and have not had much luck with finding effective open-WiFi auto-connect apps for Android.

  2. Having a kill switch would be very handy as well. Text a code to your device and the car stops or better yet will not start. You could also have it honk the horn and put on the flasher.

  3. Do they make GPS / cellular radios in one chip yet? Since all mobile phones that cost more than cornflakes seem to have GPS built-in, I’d imagined it’d found it’s way into popular phone chipsets. What about throwing an ARM CPU in there too? And I suppose the screen and camera drivers.

    It’s probably cheaper to just hack a phone, or to write some custom software to do it. The proper software, and maybe, as people have mentioned, a USB link to an MCU that can cut power to the fuel pump / ignition etc thru a relay, would be quite formidable. It’d need an external antenna, and ideally a default-to-locked mode if somebody steals the phone part. But it’s be easy enough to hide away. I think modern thieves know about the popular security built into cars, obscuring the system could be enough to put them off for the few minutes it takes to steal a car.

    I wonder what the OBD system could do, if you interfaced to it? I wouldn’t want to do it lightly, and affect safety, but could you do something like disable the fuel pump through it? It’s a popular anti-theft measure, because the thieves don’t realise it’s there til they’ve driven a way, so they don’t know to defeat it.

    My Grandad made his own car security that did the job well enough. Just hid a switch in the passenger cab that connected to some of the engine wiring. I wasn’t old enough to ask what part it was. If they don’t know where it is, and it’s taking too long, hopefully a thief will travel to a greener pasture. That’s how most security systems work, really. They don’t prevent crime, they just move it on to the easier targets.

    1. Question: do you need a voice/data subscription on your cellphone to actually read the tower IDs and signal strengths? If not then you could wardrive and store locations on something like pachube or google latitude.

    2. Greenaum. I know what your gramps was talking about. My dad told me about it or at least the jist of it. What you do is get an old model T ignition coil and connect it’s output to the metal of the car. You turn it on when you leave and anyone that touches it get a hell of a zap.
      I guess back then there weren’t a bunch of people in society that sue you at the drop of a hat.

  4. I’m curious, when I see all these projects with cell modems, about how you provide service? Can you get prepaid SIM cards or can you get a carrier to put all your cellular projects on some kind of cheap plan for you? How is this usually done?

  5. You can buy several GSM enabled car alarms that already do this. MY favorite function of the car alarms is you can listen in the car and be belligerent to the thief while you honk the horn and kill the ignition.

          1. No it currently does not. All the GSM radio is there for is sending SMS messages. It doesn’t do data–yet. The GPS receiver is VERY sensitive though, and I have had it stay locked under bridges and the like.

            Also I didn’t make it, but I did kickstarter it.

  6. In the event I where concerned about my pickup being stolen, I finally get around to installing an APRS tracker in it. As it is a thief would be likely to return it with a sympathy card on the seat for me.

  7. Cool project. For an easier and possibly cheaper option, could we just buy an old used android phone which already has most of this hardware and wire it up with a 12v to 5v converter?

    Might need to code a custom app but should be doable.

  8. Until a month ago there was a free service called instamapper. All you had to to do was get yourself a cheap ($10.00) boost mobile phone, install a GPS app and then it would send real-time gps pings to the free instamapper. WAS a great free vehicle tracking service until they shut down the site. Best part? Boost mobile’s cheapest pay-as-you-go service somehow didn’t register the data so if you had a $10.00 balance and tracked a vehicle all day, every day – you’d still have a $10.00 balance.

  9. Interesting project. I was looking for a LoJack tracking schematic and was wondering if someone has one or knows a website that has a DIY schematic for a tracker/scanner of LoJack pings. We have a lot of stolen cars here and cops are always trying to find the cars. Would be nice to have one and perhaps find some of the cars.

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