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Subject: 
Re: when they say "fresh" batteries, they mean it!
Newsgroups: 
lugnet.robotics
Date: 
Fri, 13 Aug 1999 15:19:47 GMT
Original-From: 
alex wetmore <(alex@phred.)spamless(org)>
Viewed: 
450 times
  
From: John R. Galloway, Jr. <jrg@dbengines.com>
I was having problem getting any comm working between the
IR tower (on my Mac) and the RCX.  I was using unused batteries,
but the 9 volt in the IR tower was old enough that it was only
providing 8.25 volts with no load.  Replacing it with a brand
new one did the trick.  Seems like a piss poor design to be that
sensitive to battery power.  But at least now its working.  A
USB design that took power from the USB seems like a better
plan.

I believe RS232 is in the 9v range (or maybe even 12v), so they are probably
fighting that spec there.  They could use a voltage up-convertor, but at a
loss of efficiency.  Two 9vs might have made sense.

USB really wasn't an option a year ago.  It has only recently begun to take
off.  NT still doesn't support it.

They could have powered off of the keyboard port or some hack like that, but
it would have been ugly.

alex

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message has 1 Reply:
  Re: when they say "fresh" batteries, they mean it!
 
(...) Actually it is common practice these days to power small peripherals off of the supply voltage pins on RS-232 ports as long as you're not trying to pull tooooo much juice. And even a device with a 9-volt power supply can produce higher (...) (25 years ago, 13-Aug-99, to lugnet.robotics)

Message is in Reply To:
  when they say "fresh" batteries, they mean it!
 
I was having problem getting any comm working between the IR tower (on my Mac) and the RCX. I was using unused batteries, but the 9 volt in the IR tower was old enough that it was only providing 8.25 volts with no load. Replacing it with a brand new (...) (25 years ago, 12-Aug-99, to lugnet.robotics)

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