28 SERVO 05/06.2018
in VEX competitions. Tank control was
second nature to me, allowing me to
focus on strategic driving.
We also redid and replaced all the
wiring in the entire robot, both to
save space and to eliminate all shorts.
Rigorous testing showed us that this
had eliminated the intermittency
issues we experienced at HORD, so
we moved on to mechanical
The last fight at HORD exposed a
number of structural flaws in the
frame supporting the weapon. To
solve this, we made three changes.
First, we switched from 4-40
screws to sheet metal screws with
large threads to really grab into the
UHMW frame rails so that the top
panel wouldn’t rip out as easily.
Second, we added standoffs under
the top panel to anchor it directly to
the base plate for the same reason.
Last, we ground flats onto the dowel
shaft, allowing the setscrew hubs to
grab it more securely.
Another notable issue from HORD
was the sluggishness of the weapon
spin-up. Multiple bots were able to
box rush this bot with ease at HORD.
Phantom II ran with four 180 mAh 3S
batteries in parallel, but with power
split between the drive and the
weapon so that a weapon failure
could not disable the entire
robot. Because of this, only 360
mAh was available to the
We found that the four
Silver Sparks didn’t need more
than 180 mAh to last a three
minute match, so we shifted
one of the drive batteries to the
weapon, which spun with much
more authority when it had 540
mAh (75c, according to
HobbyKing) of batteries to draw
from. Additionally, we found
out that round belts transfer
torque best when they are
stretched somewhat, so we
replaced our 10. 25”
circumference belts with 8. 5”
The final major change was
adding an alternate
configuration of front armor.
We made some modifications to the
front structure, allowing us to swap
our solid chromoly wedge for four
hinged AR400 forklets.
This made us able to slip
underneath wedge and drum bots,
and also freed up some weight for
things like modular top armor and belt
This fixed some weaknesses
against hammer bots, and also
protected Phantom II from shots like
the one it took from Underdoge.
With these modifications and our
different weapon bars, we felt ready
and able to adapt to any opponent
we could face at CIRC.
RIP King Googly. We barely knew ye.
Sparks fly as k-too sends Phantom II
into the nth dimension.