NExT & Off The Shelf Car Starting Module, but still a work in progress

Projects
1

Okay, so. Last week, I got my first implants Spark2 + NExT.

Then I ordered a Proxmark3, which arrived yesterday. Was able to get it going thanks to the very detailed instructions (thanks Amal). Used it to clone the backup key card for my Digital Guard Dawg (https://www.digitalguarddawg.com/keyless-ignition/automotive/ikey/) pushbutton start system. The system uses active powered keys, but has a backup key card like so:

20220324_182813
20220324_1828131920×1440 301 KB

Which was easily cloned with the Proxmark3.

I had to move the antenna from under the dash, because while the backup key card was easily read through the fiberglass, I didn’t suspect the NExT would be. Antenna is the black thing in my hand here:

20220324_182317
20220324_1823171920×2560 296 KB

I can start the car successfully, but the antenna will HAVE to be mounted away from the aluminum dash, but even when held at a distance, it takes some fiddling to get it to start.

Any tips on boosting strength, or sourcing/building an antenna better suited to the implant?

Either way, I’m pretty stoked that this worked (sort of) with my already installed system!

3 Likes
2

first I would ask them if you can buy a replacement antenna to see if you can get a spare… then measure the inductance of that spare antenna… then you can go about re-creating it in a new shape (with the same inductance) that may work better for you… for example, a cylindrical coil shape?

3 Likes
3

Perfect, I’ve reached out to them, I’ll keep everyone posted when I have more info. Having an off-the-shelf system that requires minimal modification would be a great tool-kit add!

2 Likes
4

Update: for $50 they sent me a replacement antenna. Kinda steep for something I’m not eventually going to use, but now I’m committed.

For much less, I also picked up an LCR meter and some 28 AWG enameled magnet wire.

Tested the new antenna in the system to verify it’s function. Same okay-ish result. Measured the inductance of the antenna:

20220406_212221
20220406_2122211920×2560 676 KB

Then it was time to play. I wound some of the magnet wire around a screwdriver shaft, taped it, sanded the ends, pulled it off and fell WAY short:

20220406_212113
20220406_2121131920×2560 608 KB

Next up was the same process with a marker. 10x improvement:

20220406_211824
20220406_2118241920×2560 680 KB

I was also able to use a special method to inspect the inside of the antenna:

20220406_213919
20220406_2139191920×2560 785 KB

A magnet was able to tell me the black core is ferrous.

Any insight into:

  1. What does the core do?
  2. Did my inductance increase because my diameter increased, or because more wire was used to get the larger diameter with the same antenna length?

I can see this turning (zing) into a fun hobby!

1 Like
5

The core increases the inductance.

For the second question should look up the formula :smiley:

I used this (https://benl.rs-online.com/web/p/ferrite-cores/4674065) ferrite rod to wind my own coil to 1.33 mH. Used some wire from old electromagnet :slight_smile:

1 Like
6

Thanks @Tehol,

I’ve played around with making a few more antennas, using new wire, and reusing the wire from that antenna. I think I have a good antenna now (the one that came with my DG Access Kit actually worked pretty well too) - I’ve built several - the best tool for testing is the small LF blinky that came with the NExT. The brighter the flash, the stronger the signal.

Now I just need to create a mount for it away from all of the metal on the car - the dash, frame, center console… All metal.

1 Like