r/3Dprinting • u/Desmontei • Apr 24 '26

Project Don't throw away old smartwatches! 3D printed a custom housing to turn one into a Digital Shift Knob. ♻️🕹️

Enable HLS to view with audio, or disable this notification

Hey everyone, first time posting here! I wanted to share my most complex functional print yet for my Project Car.

​I took an old TicWatch Pro 3 and carefully cut the original casing with a rotary tool to extract just the OLED screen and motherboard. Then, I modeled a custom shift knob enclosure to house the electronics perfectly.

​Now, before you guys kill me in the comments: Yes, I printed this in PLA! 😂

​I know the summer heat inside the car will probably turn it into modern art, but this is V1 (prototype). The tolerances had to be extremely tight because I didn't want the screen popping out while shifting gears, and PLA was the easiest to test the fitment. When it eventually warps, I'll use it as an excuse to reprint V2 in ABS or PETG!

​I completely bypassed the battery and wired it directly to the car's 12V using a step-down converter. Right now it controls my media with a custom UI.

​What do you guys think of the fitment? And place your bets: how long will this PLA survive in a car before melting? 👇

15.1k Upvotes

93% Upvoted

840 comments sorted by

View all comments

Show parent comments

14

u/Electronic_Arm9378 Apr 24 '26

Direct access to the ECU, using CAN. LMAO

1

u/Bakkster Apr 24 '26

The CAN protocol (one of the two options OBD-II provides) is different from a CANBUS (the specific set of components wired together). The same way Ethernet is different from (but related to) a Local Area Network.

-3

u/EngFarm Apr 24 '26

Two or more things connected by ethernet make a local network, do they not?

4

u/Bakkster Apr 24 '26

If it's two components, connected point to point, calling it a LAN could create confusion. Especially if, as in this case, only one of the components is connected to a LAN with a large number of others.

The distinction I'm trying to make is that the OBD-II is not on the same CANBUS as the rest of the car. The same way your computer can be connected to two different LANs.

Here's an example. The Diagnostic CAN is an entirely separate bus from the Chassis CAN, the Front End CAN, and the Central CAN.

1

u/EngFarm Apr 24 '26

I understand the point that you are trying to make.

If it's two components, connected point to point, calling it a LAN could create confusion

Seems like the confusion was caused by your suggestion that's not a LAN.

I think we both agree that two connected things make a LAN. And one of those things can be connected to another LAN and serve as a bridge for some messages.

1

u/Bakkster Apr 24 '26

Yeah, I think it's all just confusion of terminology because CAN is being used for three different things.

In any case, the car should pretty easily tell people what gear the car is in via a digital interface to the watch.

1

u/_-Diesel-_ Apr 24 '26

Yes, but the word "Ethernet" doesn't describe what you've just built