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[DPRG] toast

Subject: [DPRG] toast
From: David P. Anderson dpa at io.isem.smu.edu
Date: Sat May 24 11:52:01 CDT 2003


Capt. Bill wrote:

> I second that. 
> Very good job. I will toast your robot and you at the
> next RBNO

Thanks!  Always a good excuse to raise a glass!

I guess the word has gotten out because my web server which
normally gets about 5000 hits a day got about 30,000 hits
yesterday, almost all on the nBot pages!

Speaking of which, I have rebuilt nBot using the Pittman GM8712
motors we acquired last year, and it seems to be much more stable.
I went to a 24 volt battery pack, which also required going to
a different H-Bridge and battery charger.

I'm using the HVW L298N H-Bridge, even though HVW wouldn't send
me a schematic of the board and accused me of wanting to pirate
their design when I requested one! Here is their exact quote:

> A schematic is of no use unless you intend to knock-off the design.
> Sorry, we will not help people duplicate our products.

Is that right?!!  A schematic is of no use????!!!

What jerks.  All the other vendors I deal with, from the most lowly
serial converter to my Textronic scope, come from good companies
that seem to understand the value of good documentation.  I hate to
see this kind of nasty our-customers-are-the-enemy type mentality
infect hobby robotics.  Sigh.

For the battery charger, I'm now using an 18 cell pack of 1800 mAh
NiMH AA cells, about 24.8 volts.  After some fiddling around I
bought a really nice "intelligent" charger that can charge up to
24 cells, NiCads, NiMH, Li-ion, Li-Po (what's that?) and Lead-acid.
Check out:


I've added some images of the rebuilt platform, as well as a couple
of mpegs of the robot running around my home and office.  Go to


and scroll about half-way down the page to the "Update" section.

See y'all Tuesday.

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