Version 2 of my Switch-mounted handwire controller

[LifeIsOnTheWire]

On Reddit, I recently posted pictures of my prototype batch of my Switch-mounted handwire controllers. https://old.reddit.com/r/MechanicalKeyb ... chmounted/

I got a bunch of good feedback from everyone, and I decided to go back to the drawing board and redesign it from scratch to address every concern.

Most of the feedback I got was regarding the fact that the 1st version required 90-degree rotated switches (which could cause clearance issues for Cherry Profile keycaps). Some people wanted Alps support. Also some people expressed interest in Type-C USB.

I've decided to make the controller 3x keys wide, to allow the extra space needed for Type-C, and also to keep the keys rotated the correct orientation. The keys on the 2nd row directly beneath the board still need to be rotated 180 degrees to provide clearance for the board (this is, of course, not an issue, as many boards have south-facing switches). Also, keeping the onboard switches rotated in the normal orientation allowed support for Alps switches.

Also, a major benefit to increasing the size to 3x keys wide, was that I had enough room to provide space for a TRRS 3.5mm headphone jack, which is wired up appropriately to provide support for I2C or Serial connection for those that want to make split layout keyboards.

The TRRS connector will not be soldered to the board from the factory, as I believe most people who don't need this would rather have a low overall height on the board. However, I should be able to include the spare connector with the board for those that would like to solder it.

I'm going to be ordering a fully-assembled prototype batch of these soon, and I'll be rigorously testing them.

[zool]

I like the audio jack for external i2c. have you built one up yet(v1 that is)?

[LifeIsOnTheWire]

I like the audio jack for external i2c. have you built one up yet(v1 that is)?

No I never assembled any of the V1 boards. I was going to order all the components and solder it up, but I very quickly started working on the V2 model, which doesn't share any components at all, so it didn't make sense to order components, unless I could order LOTS to make the volume worth my while.

These boards use a TQFP package Atmega32u4, where the V1 used a QFN package. Also, the V2 uses larger 0805 sized SMD components, compared to 0603 on the V1.

I wanted to change to TQFP and 0805 because after I've sold an initial batch (to basically pay for the costs of the project), I plan on putting the files up on Github and making it open source. I figure it should be designed to allow people to get the boards made, and hand-solder them if they want to. The larger components on this model will make it more hand-solder friendly.

[zool]

I like the audio jack for external i2c. have you built one up yet(v1 that is)?

No I never assembled any of the V1 boards. I was going to order all the components and solder it up, but I very quickly started working on the V2 model, which doesn't share any components at all, so it didn't make sense to order components, unless I could order LOTS to make the volume worth my while.

These boards use a TQFP package Atmega32u4, where the V1 used a QFN package. Also, the V2 uses larger 0805 sized SMD components, compared to 0603 on the V1.

I wanted to change to TQFP and 0805 because after I've sold an initial batch (to basically pay for the costs of the project), I plan on putting the files up on Github and making it open source. I figure it should be designed to allow people to get the boards made, and hand-solder them if they want to. The larger components on this model will make it more hand-solder friendly.

cool I get where your going, I like the open source route. Only point on the home soldering is the usbc, that would real pain point for most, easiest ones are those 1/2 through hole 1/2 smd, but they are still not great. maybe open version has mini/micro? tricky choice.

[LifeIsOnTheWire]

Only point on the home soldering is the usbc, that would real pain point for most, easiest ones are those 1/2 through hole 1/2 smd, but they are still not great. maybe open version has mini/micro? tricky choice.

Yes, I was thinking along the same lines, making a Micro USB variant for people to hand solder more easily.

But then again, the USB Type-C connector I've chosen has through-hole supports, so it is actually really easy to hand solder. You just solder up the through-hole GND legs first to provide stability, and then as long as you apply flux, the pins are pretty easy.

I would say that with flux, you could probably run a soldering iron across all the pins in one swipe, and probably be okay.