Tesla owner modifies $20 Casio watch to become Model 3 car key

An enterprising Tesla Model 3 owner has modified his “old school” Casio watch so that he can use it to open his electric car.

It’s a genius hack that allows Mattia Dal Ben to simply walk up to his Model 3 and wave his wrist near the front driver’s door until the car makes its characteristic “beep” and unlocks.

Tesla provides owners with a key card for opening their cars, and the cars also open when the owner’s smartphone (onto which the Tesla app has been loaded), is near the car.

Dal Ben shared the details of the modification via Hackaday.io, saying he decided to try out the hack because he’d discovered that sometimes his Tesla keyless entry didn’t work as expected. “This usually happens in the worst of circumstances,” he write in a description of the project.

“(Water is pouring from the sky? Well I won’t open for you sorry…). Something hacky was needed….” he writes.

Seriously, we think that this hack takes Tesla ownership into James Bond territory – and raises speculation again about why Tesla is reportedly involved in the development of a smart watch with Norway’s Xplora Technologies.

While we wait for more reveleations if Tesla will give new owners their own Tesla-branded smart watch with which to open their cars, we’ll have to be content with this Casio watch hack.

With tips from a fellow hacker Dacroneous, and inspired by a similar project, Dal Ben used a classic F-91W Casio watch, which costs around $20 to buy new, and a third party NFC (near field communication) card and a bit of wire to make his own antenna.

“I didn’t want to use an official Tesla card for this because the phone call to request a duplicate, if things went south, would have been quite awkward,” Dal Ben explained in his description of the hack.

As hacks go it’s ingeniously simple if not a bit fiddly – for techie types, at least. Dal Ben says there were a series of steps, including 3D printing a new back for the Casio watch, dissolving the card from its original casing and creating the new antenna.

Fine tuning the antenna to the correct frequency, and uploading an applet loaded onto the J3A040-CL Java card brought the project together.

The project impressed the typically canny Reddit crowd at /r/Teslamotors.

“Well done man. And nicely documented too,” commented one such Redditor.

“Like it wasn’t cool enough already….. ???? Nice job!!!” said another.

“Is your name Micheal Knight? Cool mod and great write up, thanks for sharing!” said another referring to the 80s’ TV character from Knight Rider.

Dal Ben says he was also quite happy with the results – and that it’s even easier to use than opening his Tesla Model 3 using his smartphone or key card.

“The NFC communication is quite good and usable even in a pinch (more than taking out my phone or the key card from my wallet for sure) and the watch is comfortable to wear almost as it was before,” he said.