Mazda MX-5 with AKE (Advanced-Keyless-Entry) provides the convenience of locking/unlocking a car without the need to press any buttons on the key. You can keep the key hidden in your pocket.
The key fob is a bit bulky, and personally, I don’t like anything in my pockets. When I’m getting ready to leave work, I have to gather my wallet, phone and my car key, which I’m often forgetting. A couple of times I even forgot my key at the cashier station in the grocery store.
Recently I found a great blog about reshaping WV key and I decide to do the same for my Miata, as my weekend project.
The Mazda key fob is easy to disassemble; it has three major components: PCB, coin size battery and spare key.
I did quick prototyping on my 3D printer and I’m quite happy with the results. I made all the buttons functional, just in a case,
Because the battery was repositioned, to reduce overall height, I used a new low profile battery holder, which I found on Digikey.
The only reworking needed in this case is two extra wires soldered between the main board and the battery holder.
And finally, It has a 6mm thickness. It fits well in my wallet, without being too bulky.
Design files are available from the Thingiverse site.
Updated on 11/4/17:
Some other people are asking if I can add this kit to my store. To do this, I did a few modifications to make the whole assembly much easier.
Self-tapping screws are hard to use, they are too tiny and the T3 screwdriver sometimes makes them unusable. I replaced them with M2x4 Philips screws, with press-fit nuts. Second, to avoid wires soldering, I designed a little PCB, which is acting as a battery holder and as a bottom cover. As a result, the thickness of the assembly is just 5mm. Now everything can be assembled simply by putting board and battery in, and 5 screws.
Updated on 11/22/17:
After experimenting with several processes of 3D printed faceplates with embossed lettering, I decided to use laser engraving instead, on 0.8mm black Delrin plastic.
Now the construction has 3 parts: 3D printed frame, laser cut Delrin faceplate and PCB with contacts.
This kit is now available for ordering from my store.
Discussion on Miata forum is here.