Subject:
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Re: Backlit screen and external power
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Sat, 5 Jul 1997 08:20:10 GMT
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Original-From:
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root <ROOT@SNOTNOSE.WIZARD.spamcakeORG>
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Viewed:
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1377 times
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> Hi,
Hi there Joe-
> 1.Does anyone know of a backlit and/or larger compatible LCD screen?
Yes, you're gonna like this- just about any "Optrex-compatible" LCD display
can be used on the HandyBoard. There are two caveats however, most of these
displays have a 14-pin header connection and not the 14-pin inline connection
like the handyboard. This means that you will have to make an adapter cable.
It isn't hard to do- if you can spell "soldering iron" you can probably do
the work :) The other (and more ticklish thing) is that you will need to
recompile the PCODE with the right number of characters and lines. This is
also not too difficult to do, but it does take a little bit of preparation
and it helps if you've done it once before...
As for what types of displays you can get- I have used 16x2, 20x2, 40x2 on
my robots. I generally buy the displays from All Electronics or Alltronics
because the have great prices (both companies' information can be found in
the sources section on my page http://www.vnet.net/wizorg. Also most of the
companies in the sources section will send you free catalogs).
As far as the backlighting goes- many of these displays have backlights and
they just aren't hooked up. If you look at the right hand side of the display
you'll see two little sqaure pads- those are the power connections for the
backlight if you've got one. As far as what sort of power to hook up- (and
I must say this: DO YOUR OWN RESEARCH- DONT COUNT ON MY NUMBERS!!!) according
to the zeroxed sheet I got with the last 40x2 display it says 120VAC!! This
seems a little excessive to me- particularly since these displays end up in
battery devices a lot- I am personally skeptical that this is correct. But
who knows- it might be. I have not needed the backlight so far so I haven't
experimented any further.
> 2.Are the problems the with using a larger power supply than 500ma related
> only to battery overcharging and in this case can the battery be replaced
> with a larger amperage power supply?
Hmm- I think in general you would probably be ok- but if the new power supply
is very much bigger you will definately need to rework the battery charging
aspect. I haven't ever given more than a cursory glance at that part but I
suspect that all it would require is changing the charging resistor(s). If
you're wanting to increase the power supply so that you can drive motors or
something- my advice would be don't do it. If you never have excessive power
running through the board then you will never have an excessive power accident.
At $250 per HandyBoard I'd rather keep my motor power off the board.
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