FIGURE 4. Rob’s test bed.
FIGURE 5. Melty board.
(a commercial version due to size).
Motor control is via
STMicroelectronics BU941ZT
Darlington drivers, and the
accelerometer is a Freescale 200G
MMA2301EG.
Open Melt
The author, having rerun
sufficient material to add pocket
jingle without seriously enraging his
editor, now begins to generate new
material, at considerable more
effort to himself …
Rich provides information on his
robots and other projects at
www.nothinglabs.com, and has
now upgraded and refined the
software into a fully open platform.
He says: “I shifted from Bascom AVR
to C (WinAVR) to eliminate the
dependency on commercial
software. The full version of Bascom
AVR is about $130 — which is a lot
FIGURE 6. Death by
Translation.
relative to the hardware for the
project (which is only around
$50-$100).”
The code is licensed through
Creative Commons to acknowledge
his authorship. Rich also has posted
a schematic (Figure 3), a tutorial
video, and well documented code at
http://nothinglabs.com/nothing/
openmelt/.
Also on the site is a link to a
centrifuge calculator, links to parts
sources, and a video comparing
wheel types. He feels someone with
moderate electronics/microcontroller
skills could build a test platform —
similar to that shown in Figure 4 —
in a weekend. The photo shows a
test bed built by Rob Glidden,
author of the companion article in
this issue. He provides a nice segue
into the next section, discussing how
Rich’s brain melt has spread.
Open Melt is
Contagious
Showing impressive literary
skills, the author cleverly employs a
“hook,” neatly tying this section to
the eye catching article title …
Rob took Rich’s ideas and went
a step farther down the road. He
used Rich’s original Basic code as a
reference; I’ve done all of my work
using custom circuit boards and
programmed in C. He says: “There
are some neat tricks one can do to
get more out of the Melty bot
(control wise) but the biggest
problem with putting a Melty bot in
combat is making sure the insides
stay where you put them —
especially during hits!”
Kevin Barker collaborated with
Rich to build a Featherweight ( 30
pound) combat bot. Kevin did the
hardware; Rich did the electronics.
They used an impressive S28-150
Magmotor, two HFS33 solid-state
relays, an MMA2301, 200G
accelerometer, and a Pololu Baby
Orangutan B-328 microcontroller.
The bot — “Death By Translation” —
was a creative success but a combat
casualty. Kevin says: “The bot
actually did not work very well. It
spun plenty fast but due to a couple
factors, it didn’t translate very well.
It also was not strong enough to
absorb its own impacts and bent
several frame pieces in a huge hit
with Touro Feather.” Figures 5 and
6 show the custom electronics board
and the finished bot. Many more
pictures are available at
www.teamvelocityrobotics.com.
Information and photos for this article
were provided by Rich Olson, Rob Glidden,
and Kevin Barker. The Melty Brain logo was
drawn by Sean Canfield.
32 SERVO 06.2010