geekhack Projects > Making Stuff Together!
[BUILD] Magic Keyboard 2 but mechanical
Limentic:
Hey everyone, guess who’s back? ;)
I know, I know, it's been a while... But I've got some exciting updates in store for you all!
In the meantime, here are some sneak peeks to tide you over:
Stay tuned, more news coming soon... 👀
Rikudesu:
This looks amazing I would one of these kits when they're available
Rob27shred:
This is wild, very cool stuff! GL with your efforts on this, hopefully we'll be seeing a finished build sooner than later!
phanguy:
I registered to let you know that I I'm VERY interested in this project and would love to build one myself. I've been toying with the idea in my head for awhile, but I'm busy enough as it is so I kept kicking it down the road. So seeing your progress is super exciting!
Limentic:
Hi guys,
Sorry for the delay between the teaser and this post, but I didn't have time to write it up before today. A lot has happened between the teaser and now.
As you can see, I've finally taken the time to make the ribbon that connects my main board to the Apple motherboard, and to route my main board. These were the two things you saw in the little teaser I posted a few weeks ago.
I've also changed the way the Touch ID sensor will be mounted on the motherboard. I've decided to use a tactile button instead of a mechanical switch. I know this solution isn't going to satisfy everyone, and some people might be disappointed, but bear with me—it was the best solution. This, along with a lack of time, is one of the main reasons this project has taken so long to continue.
The Touch ID sensor will be mounted in almost the same way as before, using a small plastic piece on which the sensor will be screwed in place. This plastic piece will be force-fitted to the stem of the tactile button, and a fake keycap will be used as a cover for the sensor, as before.
The reason I decided to switch from a mechanical switch to a tactile button is simple: the length of the sensor's ribbon and how the sensor plugs into the connector.
The connector could not be mounted on the top face of the custom mainboard because the connector on the ribbon needs to be facing up, and if we want to mount the sensor on top of a keycap, the connector on the ribbon would face down. The only way to avoid making another custom ribbon (which could degrade signal quality due to introducing extra connectors on the line, especially since we still don't know much about the signals of the Touch ID sensor) was to mount the connector on the bottom face of the mainboard, with the ribbon going through the mainboard. This way, the ribbon connector would be facing up, and the sensor could be mounted facing up.
The other issue with using a mechanical switch is its travel. It was too long and couldn't be reduced for the sensor ribbon to reach the connector on the bottom face of the mainboard. So, I decided to use a tactile switch instead because the travel is shorter, and the button can be pressed with less movement.
I think it could theoretically work with the mechanical switch, but the way the ribbon would have to be bent, in my opinion, would stress the ribbon too much and potentially damage it.
I didn't want to take that risk, so I decided to use a tactile switch instead. I know it's not the perfect solution, but it's the best I could come up with. I still think it's a good solution because you don't press the button that often, it will still look almost the same as the other keys, and the same principle is used in the original keyboard to avoid too much movement of the ribbon.
Here's a little schematic I made to explain the issue:
With this out of the way, I could move forward and route the mainboard. As you can see, I've length-matched the traces on the mainboard as well as on the Touch ID ribbon. I know it's not perfect—there are many factors that could have been taken into consideration—but since I don't have much information about the signals of the Touch ID sensor, I decided to length-match the traces as best as I could and hope for the best. At worst, it won't make a difference; at best, it will work.
Here's the mainboard:
And here's the custom ribbon:
After that, I double-checked everything and sent the files to PCBWay (still not sponsored, but I would love to be, this order was pricey) to have the mainboard and the custom ribbon made. I use PCBWay because I can get the TF22-16S from them without having to buy the full roll, and as a bonus, they offer good quality and great customer service for the price.
Even though I double-checked everything, I made a mistake. For whatever reason, the 0805 footprint for the Caps Lock LED was removed from my board layout, and I didn't catch it during my final check. So, in the Gerbers I sent to PCBWay, the footprint was missing. I only noticed it when the board was already in production. It's not a big deal—when I receive the board, I'm going to scrape the solder mask a little bit, use a lot of flux, and solder the LED directly to the traces. It’s not the best solution, but it will work.
As promised, here's the full GitHub repository with all the files I used to make this project:
https://github.com/limentic/the-hephaestus-mod
I hope you enjoyed this little post, and I'll see you next time when I've received all the parts and start assembling everything.
Pray with me that everything works as intended!
See you next time!
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