Twin Tweaks ...
WIRING UP THE CONTROL SYSTEM FOR THE FIRST TIME.
CHECKING THE POWER FROM OUR REGULATOR.
DRIVING PROTOBOT WIRELESSLY.
72 SERVO 06.2011
had to get a little creative to power the TRENDnet router.
The solution was a simple voltage regulator circuit using a
7805 IC and a couple of capacitors. Because of the strict
warnings that came with the router that any voltage over
5.1V could cause irreparable damage, we thought it best to
check our circuit with the infinitely useful multimeter before
hooking everything together. Sure enough, the regulated
voltage was in the Goldilocks zone with an output of
5.028V. We couldn’t have gotten a better deal had the
Priceline negotiator advised us that we could name our own
voltage!
Physically wiring up the components was
straightforward. The 2CAN and CANipede come with free
wires that were easily crimped into the sockets necessary to
connect to the power distribution block. The TRENDnet
router comes with a USB power cable that allows the unit
to be powered from the USB port on a computer. We cut
the end of the cable that attached to the router and
extended the wires on the other side, so they could
comfortably accommodate the required sockets. The
compact components were easily mounted on an
electronics shelf on Protobot, and a few strategically placed
strips of Velcro were able to keep everything sitting tight.
The manual sagely suggests a bench test to make sure
everything is communicating properly. The first step is to
make sure that the 2CAN and the CANipede have updated
firmware which can be done with the 2CAN Firmware
Utility. The Firmware Utility has a fairly self-explanatory user
interface that gives helpful feedback as you go through the
steps of establishing communication with the 2CAN. The
only part of this process that was a hassle was synching the
IP address of the computer with the 2CAN. The Firmware
Utility ostensibly gives you a way to change the IP address
of your computer through the utility itself, but the changes
never seemed to take to our computer. Thankfully, the
manual also walks users through how to change the IP
address of their computer manually, which worked like a
charm.
After updating the 2CAN, you can open the Web
Dashboard to update the CANipede. The Web Dashboard
can be used to get helpful feedback from the entire control
system, with the CANipede being just one possible node.
Other nodes can be easily wired in parallel, but initial
implementation of the system does not require anything so
involved. Our only caveat about loading the firmware is to
be cognizant of the jumper on the CANipede. The jumper
can set the CANipede to termination resistor or bootloader
mode. For the purpose of updating the firmware, make
sure the CANipede is in bootloader mode.
After updating the firmware, the robot is ready for the
first bench test. The bench test uses the RCS to activate a
solenoid switch. No actual solenoids were harmed (or used)
in the making of this bench test, because the CANipede has
LEDs that light up when each solenoid switch is activated.
Using a USB game controller like the dual joystick model
from Logitech is recommended. We didn’t have one on
hand, but they can picked up at your local electronics store
