Re: TI-H: Keyboard

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: Keyboard
From: rabidcow@juno.com
Date: Tue, 17 Oct 2000 20:39:06 -0700
Reply-To: ti-hardware@lists.ticalc.org

i have an old supposedly nonfunctional webtv keyboard.  it's controlled
by a zilog keyboard controller (marked "zilog 3475 / twm-0102")
zilog's ir keyboard controller chips take 15-40 mA (depending on device)
of active current, and a few uA in standby.  if they're designed
properly, they'll be on standby most of the time, so this would not draw
much current (i mean, really, they designed this thing to run on two aaa
batteries for months at least, right?)

you'd need to build an ir receiver, and maybe have a microcontroller
convert to the ti-protocol.   worry about any current draw there, unless
you want to have three sets of batteries.

as a bonus, you get a wireless keyboard for your calculator... 

-josh


On Tue, 17 Oct 2000 22:07:55 BST "Simon Trimble" <gingerno1@hotmail.com>
writes:
> 
> Na, you dont want to use a ready-made keyboard. You need to design a 
> 
> keyboard yourself that is controlled by a uC. That way it will only 
> consume  
> < 1mA insted of  > 1mA. It could also possibly be wired into the 
> calcs own 
> power supply when it is drawing that small current.
> 
> You could use the keyboard for the keys, but i suggest re-wireing 
> the keys 
> into ure own uC.
> 
> What u think???
> 
> 
> Simon.
> 
> 
> >From: Nivek <nivek_ent@yahoo.com>
> >Reply-To: ti-hardware@lists.ticalc.org
> >To: ti-hardware@lists.ticalc.org
> >Subject: TI-H: Keyboard
> >Date: Tue, 17 Oct 2000 04:56:21 -0700 (PDT)
> >
> >
> >remember i asked about a keyboard for the calculator a while back?
> >well I have been thinking, and you know the guy that said the 
> keyboard
> >would be a power sucker?  A WEBTV keyboard doesn't use a lot of 
> power,
> >i saw one at Target that used one AAA or AA battery.  And they are
> >small.  Just a thought but it might work.
> >
> >=====
> >Nivek
> >Nivek_ent@yahoo.com
> >http://come.to/NivekEnterprises
> >
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>
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