Build Log: Bluetooth, hot-swappable 60% keyboard project

[nubbinator]

So, for a while, I've been thinking it would be cool to try and make a BT keyboard that I could take with me.  I've been looking around for a bit to try and figure out how to make this possible.  After a lot of research and a fair bit of putting things together, I think I finally figured it out, but some double checking would be nice.

This project will be built around two things, my hasu 60% Alps board and the Bit-Trade One USB2BT module.

Summary of parts so far:

Parts on hand or in the mail:

• Bit-Trade One USB2BT Bluetooth adaptor - Everything I've seen indicates that this should enable me to turn any keyboard or mouse into a bluetooth enabled device.  I still have to assemble it and take it for a spin on my HHKB and other 60% boards.
• Ultraslim USB Hub - Since I want to have everything internal in a case, I have to go for the smallest I can find with the best layout.  I couldn't find a small USB hub that was completely horizontal that only had one additional slot, so I had to go with this.  It's two more hubs than I need, but it's also super small, so that should help me fit it inside of a case I plan on making.  I hope future iterations of the USB2BT module have an additional USB input on it so you can bypass needing the hub or, better yet, they build the BT module into the device.
• USB BT adaptor - Unfortunately, the USB2BT doesn't have an integrated BT module (which it should given then price, IMO), so I have to buy one.  This was the slimmest and cheapest I could find that used a newer BT iteration.
• Short right angle Mini B to left angle USB A - this will be internal to the case and go from the keyboard to the USB hub.  This will let me be able to swap in any standard 60% PCB and it's small enough that I should be able to integrate it into the case.

Parts I'm looking at:

• Adafruit Powerboost charger - I need some input on this to make sure it's not pumping out too much power since it's at 5v, but it should, from what I can tell, let me charge the battery in the case without removing it and also let the battery power the BT module when the cable is unplugged.  Ideally I think I'd need a switch between this and the USB2BT module so I could turn off the module instead of always having the power on.
• 2500mah LiPo battery - to power the keyboard and, hopefully, make it so I can go at least a month between recharges.
• PCB pins/receptacles -  There are some Mill Max PCB receptacles that look like they should work for Alps on my hasu board.  E3E showed me some, but I think they'd be too large.  They're also about twice the cost of some of the others I've been looking at.
• Hasu 60% Alps PCB and plate along with stabilizers and various Alps switches

I'll do more updates as I work on it more, but if you see anything that might not work or if you have any suggestions, please pipe up.

[piemancoder]

This sounds like it's going to be amazing. Which switches do you plan on using?

[Sent]

Bluetooth 60%.  Yes.  If I was able to I would convert all of my boards to bluetooth.  No cables, please.  Interested to see how this all turns out.  Good luck, Nubbs.

[nathanrosspowell]

So if I understand correctly you are going to:

• Use battery pack to power the USB hub.
• Use the bluetooth adapter for a connection between the hub and your laptop.
• Plug the keyboard into the hub.
• Plug the bluetooth module into the hub so you can connect a mouse

So in theory you just need to turn on your mouse and keyboard and you have wire free connectivity all around? Very cool. When building everything you should be able to remove all of the USB connectors and just straight up wire them in to save on some vertical height.

I'm wonder what the input latency of the mouse would be like if it needs to go through two bluetooth connections. Probably not noticeable for normal laptop operation.

I don't have any experience in this area for building (I do have a hasu BT HHKB), but here is Jacks Planck PCB bluetooth modification and parts list: https://redd.it/3psx0q

[nubbinator]

So here's the connection order: keyboard to USB hub, USB hub to BT module and USB2BT module, USB2BT to power hub which then connects to the battery and, when needed, external USB.

There is no mouse involved, it's purely for the keyboard.  The USB2BT module requires a BT module to work.  Most of the examples I see people use are a

[Leslieann]

They really could make that a lot nicer by incorporating the bluetooth and just leave the one usb port for the keyboard to plug into.

Here's the layout. Power can be from a cell phone charger or battery pack.



I was going to say you could probably find a smaller, cheaper USB 2.0 hub, but given the price on the one listed, that's hard to beat really, good find.  Most USB hubs, if they are single layer, are all similar in height once you take the housing off, so no real need to find a super slim version, but again, that's a nice find. One problem you may find is drivers for the BT module, I've had several that needed special drivers installed, so they might not work on that.

I love the idea of wireless keyboards, wireless is so elegant, I just always find them more problematic that they're worth. This however, might be worth considering for the Magicforce though. I would probably consider a dual use external port though, one that could charge the battery and/or use in wired mode.  I might be able to put it all inside... Maybe.

[bocahgundul]

This one gon be a big project

wish you the best of luck and I'm gonna see what I can help for this!

[nubbinator]

I really wish that they included the bluetooth module on the USB2BT device or, at the very least, had a breakout board or "backpack" board (adafruit's term) BT module that you could attach instead of having to use a hub and a BT module.  It would use up less space and be more elegant.

The huge problem with the USB hubs is that all of the ones I found with fewer USB ports were horizontally stacked hubs, vertical hubs with a horizontal plug, or twice as thick as the one I got.  That was the slimmest one I could find that took up the least amount of space.  I would kill for an even smaller one, but I couldn't find one.

The module didn't say anything about drivers and the stuff I say indicated that people didn't have problems with it, so I have my fingers crossed.

And I would love to do a dual use external port, but the only ways I see it being made doable are a huge PITA and probably outside my know how.  If you have any suggestions, I am definitely open to it.  I believe you can plug the module into the computer and use it wired (I can't read Japanese, so I'd need someone to confirm).  If that's the case, there's probably a not too difficult way to set it up so that I can charge the battery and use it wired.  Again, any suggestions there would be greatly appreciated since I'm currently in the getting things figured out stage.

[Leslieann]

They are also called daughter boards.

Use a cell phone external battery pack, they have their own charging circuits built in that stop charging when full, something the batteries you listed lack. Find a small one and rip the guts out of it.

Here's a few small ones I found, cheap.
1 Thick, but small in other dimensions.
2 Thin but large flat battery.
3 should be small enough, but short battery life.

Wiring
Your external port should have power wires running from the external port into the lines running from the battery pack, to the USB2BT device. Black to black, red to red. That should be able to charge the battery and power the USB2BT device at the same time. Because it's powered (though not sending signals), the hub can power the keyboard. This could be altered too but adds more complexity, simple is better, it's less efficient since the USB2Bt and hub needs powered, but it's not like we're talking about wasting 500 watts.

The signal wires is where it gets complicated, we will use yellow and green for our signal wires (which wire or color doesn't matter here). You want the yellow signal wire to go from the keyboard port to both the external port and the USB hub. The other wire needs to go from the keyboard to the center pole of the switch. One outer pole on the switch directs it to the external port, the other pole directs it to the usb hub. I don't believe you need to interrupt both signal wires.

Keep in mind that a common USB 2.0 port will be hard pressed to really charge this at any decent rate of speed. If you want to charge it fast while using it, use a powered hub or put a switch between the neg running from the battery and external and redirect it to the keyboard (cutting out the usb2bt device and hub from the circuit).

[heedpantsnow]

Cool, watching dis.

[MOZ]

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