Single key USB keyboard. Help please

[toriw]

Hi everybody.

I would like to build a single key USB keyboard being this, the simplest, cheapest and smallest possible. I have been reading all you fantastic work here but I could not sort my ideas.

I would like to create a portable 'a' key for example. I don't want anything programmable, only one character and it would be great if it would be "plug and play" type.

I tought about using an old usb keyboard, but i am looking for something smaller as long as i will not need so many pins.

If anyone could tell me if this can be made in a easy way i would be very gratefull ( I am impressed by all the work you are doing here, maybe i am asking for the impossible :) )

thank you a lot!

[kishy]

If you want to just do it the messy kind of dumb way, you could get a typical USB membrane rubber dome keyboard and hack it up with a saw, scissors and the like 'till it was down to just one key, then reconnect what's left of the membrane matrix to the controller. Presto, mission accomplished.

There are better ways though.

What, exactly, are you trying to do with it? Someone with microcontroller experience could easily whip up a design to send a typically unused scancode to do something special I'm sure.

[trievalot]

you could use a Model M, remove all keys except one , plug into PS2 to USB and viola

[kishy]

you could use a Model M, remove all keys except one , plug into PS2 to USB and viola

I think that would not be so good, since the goal doesn't seem to be getting a keyboard with only one functional key, but rather one key available to be mapped to stuff that could be stuck beside your usual keyboard (at least that's how I'm interpreting it).

[Rajagra]

I looked in to hacking one of those EcoButton devices to do a similar thing, but it seems to be fixed in how it works (""hits "windows key + R", waits a second, then types in "ecobutton" then it presses enter. "")

Maybe it can do what you want, or maybe someone can figure out how to hack it properly to send a single keystroke.

Often seen cheap on ebay.

Edit> If you're feeling technical, something along these lines might be good.

[In Stereo!]

http://www.usbgeek.com/prod_detail.php?prod_id=0669

Or something...

[Mnemonix]

Or take a look at the 1-Key-Keyboard.
A bit like the panic button, but you get to build it yourself.

[toriw]

Thank you eveone. You are very kind.

I have a computer and it's keyboard has the "4" key broken. I know that there are plenty solutions to type the "4" char like using the numpad but i tought that it would be great if i could build my own "4" key to compliment the existing keyboard and use it to type the $ character.

I like this very much from http://blog.flipwork.nl/?x=entry:entry081009-142605:

What does it do?

This 1-Key-Keyboard can be plugged into any computer and will be recognised as a standard USB keyboard.
When closing the switch, the keystroke ‘]’ will be sent.
When opening the switch, the keystoke ‘[’ will be sent.

That’s all.  

That's all Seems to be small enough, cheap and portable. I will try this I think. Time to unwrap the old soldering iron. If you have more suggestions about this i will be very happy to read them. I will tell you if anything good (or bad) happens.

[lowpoly]

The Teensy might be easier. Then get a Cherry MX switch, a keycap and build a case.

[lowpoly]

The Teensy might be easier. Then get a Cherry MX switch, a keycap and build a case.

Is your keyboard beyond repair?

[Rajagra]

http://www.usbgeek.com/prod_detail.php?prod_id=0669

Or something...

Also from that site... I think I worked out why Ripster's USB hubs keep failing. At least it keeps his Topre space bars safe.

And one for the Cherry fans.

[itlnstln]

Sorry.  I'm not buying anything from a subsidiary of a company called "GizGeek."

[Hak Foo]

Aw c'mon.  There is a lot of fun stuff there.

Wireless keypad/keyboard

Show Image

It's a HK outfit.  Not exactly the best reseller ratings.

These HK outfits like DXtreme do have the weirdest stuff though.

What I don't get is why nobody sells a $20 USB programmable keypad, even with rubber dome switches  It's hilarious that the closest I see are:

* odd-lot Cherry products
or
* the X-Keys product at $100 for 16 keys.