Key battery replacement & reprogramming. Permanently serviceable key fob | BMW e46 e38 e39 e53

In this video, I'll show you how to replace the battery on the BMW e46 key fob. Unfortunately, BMW didn't make these key fobs serviceables from the factory, and they want you to go to their dealerships and buy a new one for approximately 120€. That's why people normally cut them along the seam, replace the battery, and then glue them back together. This solution is fine, but I decided to design & 3D print a plastic case to be able to assemble/disassemble the key as many times as I want, even though you may only need to do this once every 10 years.
You can download the files and print one if you want. The link to the STL files, it's for free:

https://www.thingiverse.com/thing:622...

0:00 The problem
1:28 Part1: Key battery replacement
2:54 Battery specs
3:02 Part1: Key battery replacement
4:00 Desoldering old battery
5:03 Installing new battery
5:19 Key synchronization issue
5:48 The solution to the key synchronization issue
6:14 Key synchronization
6:54 Part2: Making a key fob case
7:38 Iterative design process
11:33 Final design & full assembly of the key
12:01 Aesthetics
12:04 Final result
12:15 Requirements validation
12:39 Link to files in the description
12:52 Regrets & Coffe