Bluetooth addon pack w/built in battery [HALP PLEASE!]

[bueller]

I've been looking at options for adding bluetooth to existing keyboards and came across the Bluetooth Keyboard Adapter from Handheld Scientific. While this looks good I think it can be done using existing parts cheaper and in a more 60% friendly size that can be adhered to the back of a Poker next to the USB port. I've done a basic drawing to illustrate what I'm thinking, what I'd like is input from members regarding the requirements and parts below.

PARTS

• BlueFruit EZ-Link or EZ-Key if the link doesn't support HID.
• Lipo Battery (800mah+ - depends on size)
• Lipo Charging Circuit

FEATURES

• Bluetooth connectivity for 60% boards w/ the usual connect button
• Ability to pass the USB through to the keyboard while charging the battery
• Small form factor to allow it to be adhered to the back of the keyboard (<= 1" height)

The second feature is the one I'll need the most help with, I'm pretty sure I'd need some way of switching between sending the USB to the bluefruit or the keyboard based on whether it's connected to a PC. So if connected to a wall wart it just charges the battery and if connected to the PC then it charges the battery and passes the USB through.

Any other comments or concerns regarding the parts I've chosen are welcomed as well!

[SpAmRaY]

Watching this with interest!

[Nickelbawker]

I really like both of the pokers and pure so this is a possible option for my wireless 60%.

http://www.keyboardco.com/keyboard/usa-majestouch-minila-air-67-key-soft-linear-action-bluetooth-keyboard.asp

No specs on Battery life... guess ill check into it elsewhere than the official site.

and it's layout isn't as traditional as the poker pure I believe. Prefer traditional.

So considering waiting for this and or building one.

Not only that but the big plus is that you get full wired performance when you want / need it.

One other thing is with all this nasty weather in the U.S. I would suggest not investing in a lot of batteries in the winter time as cold weather provides the most damage to batteries.

http://www.ebay.com/itm/like/400625098633?lpid=82

BTY 3200mAH AA rechargeable batteries can be configured into a series to achieve proper voltages. Downside to such high amp hour is longer charge time but you get that in use so pretty much if you charge while you're not using you should never run out. I got one pack 5$ and rebuilt my 20$ dremel with it bought another pack and they never worked and never got reimbursed. Not sure if there is a easy way to charge either but I have a lot of DC 1amp 15watt usb chargers from the dollarstore that work on a lot of stuff.

[bueller]

Yeah I want this to be something that can be installed on existing keyboards, I don't like any of the options with bluetooth built in.

[Nickelbawker]

Yeah I want this to be something that can be installed on existing keyboards, I don't like any of the options with bluetooth built in.

Filco lasts 6 months I guess. Approximately but I'm more interested in having a device that can also communicate through PS/2.
Also roughly 40$ cheaper and lighter weight makes your idea more attractive.

[bueller]

Anyone? Really just need some insight into the USB switching, I could move ahead without it but it would be better if I could get pass through happening.

[AGmurdercore]

I really wish that i was able to help you but sadly i have no knowledge on this matter but i will watch this with great interest as i love the idea. If this becomes a thing i would be interested in building one for myself too. Good luck!

[pasph]

I may be wrong but i think you need this instead
http://www.adafruit.com/products/259#Description
"Separate JST connectors for battery and load system so batteries don't have to be removed for charging"

[bcg]

EZ-Link won't do what you need, but the EZ-Key HID will.  However it won't work as a keyboard converter without a microcontroller, but if add a microcontroller into the mix you can send Bluefruit EZ-Key 6-key HID reports using the serial connection, provided it is EZ-Key HID 1.1 or 1.2.

I integrated a Bluefruit front end to tmk_keyboard firmware a couple months ago, I use it and it works fine.

I'm still working on a power circuit for pass-through USB switching.  The larger USB lipo charger from adafruit is more along the lines of what you need, but unfortunately they don't break out the data lines from the usb connection so you we need to account for that.  Also the voltage that comes out of the load terminals is ~3.7V so if your keyboard expects 5V you would need a boost converter.  Rechargeable USB battery packs are relatively cheap tho, not much more than the lipo+charger from Adafruit and would have a boost converter built in, so it might be faster/better/cheaper to gut one of those for the battery and circuitry.  Also I believe hasu is working on that problem for his replacement hhkb controller

I'm almost finished writing a tutorial on this which I plan to post soon if you are interested - I intended to post one a while ago but I've gone through a couple iterations of this design and I've been really busy

Here's my original post if you're interested:

http://geekhack.org/index.php?topic=50183.0;topicseen

[bueller]

Thanks for the info bcg, you've confirmed a lot of the thoughts I was having and gave a lot of insight in other areas too!  Will give that link a read

[atlas3686]

This would be amazing, don't have any insight to add unfortunately but will be watching this closely.

[Nickelbawker]

hmmm have you started ordering stuff yet or are you still designing?

Here's a direct link to the EZ key

http://www.adafruit.com/products/1535

Link to 1200mah battery, this looks like what we will probably use since I don't seen 850mah, its still pretty small looks like its almost flush with Poker II edge.

http://www.adafruit.com/products/258

[bueller]

Still looking around to see what's available from China, want to try and get the price a bit lower for the batteries and charger.

[Nickelbawker]

Hey

this battery is on sell for really cheap just got the email!

http://www.ahappydeal.com/product-174584.html?utm_source=mail_api&utm_medium=mail&utm_campaign=regular.0407u1&email=b2t8bm1lc2VjaGVyQGdtYWlsLmNvbXw2NjI=

Let me know if you're working on this!?

[agodinhost]

Whatever LiPo you get remember to get one "low discharge" battery.
It's important.

[bueller]

Really wish I had some positive info on this but unfortunately I'm without work at the moment so no new toys for the time being. Hopefully I'll be able to buy all the parts and prototype something in a few months.

[bcg]

FYI - I wrote a tutorial related to this:

http://geekhack.org/index.php?topic=58015.0

Adding in the part for USB shouldn't be TOO hard... this post might be helpful

http://geekhack.org/index.php?topic=58048.0

[bueller]

FYI - I wrote a tutorial related to this:

http://geekhack.org/index.php?topic=58015.0

Adding in the part for USB shouldn't be TOO hard... this post might be helpful

http://geekhack.org/index.php?topic=58048.0

Cheers bcg, I'll take a look!

[Nickelbawker]

Hey guys thinking about building one of these soon for a Poker II let me know any updates