Twin Tweaks ...
WIRING UP THE SRF-05.
THERE CAN ONLY BE ONE ... BATTERY PACK.
PRIME REAL ESTATE.
70 SERVO 09.2012
improving performance, and that sometimes the “if it isn’t
broken then don’t fix it mentality” can actually lead you
down the primrose path.
With one battery pack eliminated, we still needed to
get rid of one more. The 9V battery powered the board
electronics for the Mark III brain. We were worried that
the higher voltage LiPoly pack might be too much for the
board electronics to handle, but a quick look at the board
specs revealed the comforting news that the Mark III brain
had onboard voltage regulation that could handle up to
16V, making the 11.1 LiPoly pack well within the
Goldilocks zone. The only remaining task was to make
sure the LiPoly pack could connect to both the board
terminal and the TinyESCs.
The LiPoly pack has two connectors branching off
from it: a JST connector for the power and ground leads;
and a larger header for charging. The header for charging
had more leads going into it than we were used to
seeing, and it turns out that it is normally charged by a
device that both charges and balances. A balancer ensures
that all cells are charged to the same state of charge,
which ensures that lower capacity cells do not unduly limit
the entire pack. This seemed like an appropriately
competitive feature for a competitive chassis, so we would
do what we needed to ensure that this was the only
battery pack the bot needed.
Since the LiPoly pack was capable of meeting all of
the bot’s power requirements, we just needed to make
sure that it was wired up correctly. Last time, we just
twisted the power and ground leads from the respective
TinyESCs together and stuck them into the JST connector.
Now, we also needed leads to go from the JST connector
to the terminal block on the Mark III board.
To avoid butchering the wires on the battery pack, we
acquired a JST socket for the battery connector to mate
to; the JST socket had a power and ground lead to solder
the TinyESC leads to and to also add power and ground
leads to go to the Mark III board. With this setup, we felt
like the wiring on the bot was much more up to our
standards of cleanliness, and we were able to store the
battery under the brain which was held in place by a
bracket fastened to one of the main standoffs protruding
from the base.
With the bot down to one battery pack, it was finally
starting to look like something that could dominate the
dohyo. From what we had seen from the kit so far, its
efficacy as a Sumo robot was fairly beyond approach.
Serial tinkerers like us, though, are often just as interested
in a kit’s potential for areas beyond its intended scope. In
particular, we were interested in the Cobra’s ability to act
as a platform for electronics experimentation.
Whenever we come across a new sensor or come up
with a new mechanism we would like to test, we usually
don’t like going through the rigmarole of cobbling