A better alternative are chargers
with delta peak detectors. These
can tell when the battery is charged
and then will switch it over to trickle
charge and turn on an indicator
light to let you know.
The cheapest ones have low
output current and so need several
hours to bring your battery to full
charge, but you can plug your
battery in and forget about it. If you
have a slow charger, you may need
two or more batteries to get your
robot through a full day of fights.
You can also buy higher current
chargers that will recharge your
battery in an hour or less but they
will cost you more.
The pursuit of energy density
will ultimately lead you to Lithium
Polymer (LiPo) batteries which have
the best performance available.
However, LiPo batteries and their
chargers are outside the scope of an
article about cheap power. SV
All photos are courtesy of Michi Mathias.
ROBOT PR FILE
THE ULTIMATE ANT
Due to circumstances beyond my
control (plus a bit of laziness),
I’ve been out of building insects for
about four years. I follow the
technology escalation on various
forums, particularly the Antweight
forum on Delphi Forums (http://
forums.delphiforums.com/ant
weights). As I creep back into
building, I realized the state-of-the-art in components moved on without me. So, I started a thread to
garner the fruits of the best insect
bot building brains. “We” (they)
built the parts list for the 2009
Ultimate Antweight full combat bot.
There was surprising little disagreement on the top one or two brands
of hardware in each area.
As we’re taking a short break
from our “Top Bot” profile series,
(due to the apparent exhaustion of
Event Organizers, who slipped a bit
After being battle tested in 51 fights
through three major upgrades, Babe was
very competitive in the 2005/2006 season.
● by Kevin M. Berry
in getting brackets into BotRank), I
decided to use this wealth of data
to profile the 2009 Ultimate Ant.
My baseline is my tired old
2005 machine Babe The Blue Bot.
At the time, as a box bot, it
approached the Ultimate level of
technology. Now, it’s hopelessly out
of date except for possibly in a few
areas. Babe has appeared numerous
times in SERVO, both in my articles
and as a standard header in another
series. Here are the specs:
• Drive Motor: Four Copal 60:1
gearmotors
• Wheels: 1.75” Lite Flite
• Hubs: 4 mm Lynxmotion
• Drive ESC: Sozbots Classic
• Drive Batteries: 350 mAh LiPoly
Triple Cell 3S 11.1V pack
• Weapon: 0.040” Ti 6Al-4V wedge
• Armor: 3/32” hardened kevlar
honeycomb with 0.012” 6Al-4V
titanium overlay
• Radio System: JR Quattro 75 MHz
PPM with GWS four channel
receiver
• Power Switch: RadioShack
• Fittings/Parts: Zip ties, hook and
loop, aluminum, UHMW
I went in thinking the only
components on Babe that might still
be state-of-the-art quality are the
armor and the LiPoly pack. Sneak
peek at the results: Lite Flites are
still current and I’m not giving up
on my Lynxmotion hubs.
For pumping the forum’s
expertise, I laid down the following
ground rules (which later caused
some trouble, explained under the
Motors heading).
“Assuming the following: unlimited budget for components (but
value matters too, not just cost);
two driven wheels; spinner (drum,
disk, horizontal, vertical, whichever);
2.4 GHz radio system; Robot
Fighting League compliant. Don’t
worry about raw materials or manufacturing unless very specialized.”
This post accomplished exactly
what I desired. Eleven builders
posted their lists, along with some
advice from other seasoned
veterans. The results were
surprisingly consistent.
Drive Motors
Nine of the 11 builders opted
The 17:1 Maxon was the
overwhelming choice for
driving the Ultimate Ant.
28 SERVO 05.2009