Mazda MX-5 with AKE (Advanced-Keyless-Entry) provides convenience of locking / unlocking car without 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 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 tis case are two extra wires soldered between main board and the battery holder.
And finally, It has 6mm thickness. It fits well in my wallet, without being too bulky.
Design files are available from 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 taping screws are hard to use, they are too tiny and T3 screw driver sometime 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, thickness of 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 face plates 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 face plate and PCB with contacts.
This kit is now available for ordering from my store.
Discussion on Miata forum is here.