Team Unlimited visited the headquarters of FIRST in Manchester
NH on June 26th 2008. Joann Halloran was kind enough to show us around the
facilities, and we were able to meet with FTC Director Ken Johnson as well.
James Rahaim from the FIRST technical staff was generous with his time,
answering a whole list of questions for us concerning the new Tetrix FTC
building system. Following are photos from our visit, and the questions
that were answered (also on our blog).
Q: How many controllers can be operated on the new system?
A: Two controllers can be used to operate the NXT for the new FTC challenge. The
system is laptop based and transmits controller data to the NXT through a blue
tooth dongle. In competition there will be a central computer being operated to
control all the rounds. Each NXT has a unique address that allows Bluetooth
signals to be sent to it in order to perform functions during operator mode.
Q: What does the controller connect to in order to operate properly in operator
mode? Are there any limits on the amount of robots that can be run at any given
A: As stated above, a central competition computer will run the rounds.
Switching out of autonomous mode will be determined by this computer also. The
Bluetooth dongle on this computer will communicate to NXTs on the field. There
is no theoretical limit for this system, but a practical limit must be
introduced or else a lag occurs in the system with too many signals being
received and transmitted.
Q: How are the drive motors controlled? (e.g. H-bridge, speed controller, etc.)
A: There will be multiple “black boxes” mounted on the robot to control the
motors, daisy chained to a single NXT sensor port. There are 2 of the DC
controllers units (each DC controls two motors) and 1 of the servo control units
(driving up to 6 servo motors). LEGO NXT motors are controlled directly though
the NXT controller.
Q: Who are the new sponsors for next years providing the metal, sensors,
A: HiTechnic, National Instruments, and Pitsco (LEGO Education). Pitsco is
proving a large portion of the metals for the new kit, custom made.
Q: Are the parts in this kit commercially available?
A: Yes, the providers of the parts realize that the parts will be under stresses
from usual competition strains. Seeing this, new parts will be available in the
form of kits, such as a metals kit that includes a selection of metals in one
kit. (NOTE: This is similar to the Aluminum kit that Vex provides that has many
metals in one kit, no idea on prices yet)
Q: For next season, will teams be able to buy more of these metals, sensors,
etc.? Will there be kit restrictions?
A: Teams will be able to purchase new parts for the kits, for spares, additions,
etc. Dealing with kit restrictions, the teams will have their electronics
limited, including motors and sensors.
Q: What is the average range for the controller in operator mode?
A: The range for this system is about 30-50 ft, more than needed to run on the
competition field. One can see a substantially larger distance depending on the
particular dongle and area where the robot is being driven. (e.g. a large open
room without obstructions will get a much larger range than a cluttered room
full of boxes).
Q: How many types of wheels will be available in the kit?
A: There are two sizes available in the kit as of right now. In the demo, most
of the teams used the larger wheel to get more speed from their robot, but there
were two wheel sizes included in the kit.
Q: How many control channels are available?
A: There are two joysticks, an eight way d-pad, and eight buttons. (NOTE: The
controller we used was similar to the Logitech PS2)
Q: What vex components in addition to the metal can be used next season? (e.g.
wheels, gears, chain, etc.)
A: For the time being only the Vex metal will be allowed to be used in the
competition for next year.
Q: Will we able to modify the Lego and metal components?
A: You will be able to modify the metal components as you have been allowed to
for FTC competition for the 2007-2008 season. The Lego components will not be
allowed to be modified at the current time for competition.
Q: Will there be a rotation sensor provided in the kit?
A: Yes, there will be a rotation sensor in the new kit. The one that was
installed on the demo robot (they were US Digital rotation sensors) may not be
the final sensor included in the when it is released.
Q: How open is the kit? Can we use components not provided in this kit? (e.g.
other metals, other sensors, etc.)
A: The kit will be relatively closed, there will be the ability to buy new metal
for the kit. There is the possibility of other materials being added to the kit
to allow teams to fabricate parts for their own use.
Q: Will there be continuous rotation servos that can be purchased for the kit?
A: There will be 170º / 180º servos. No regular servos can be used besides the
NXT Lego motors provided with the kit. The 170º / 180º servos will not be
allowed to be modified to become continuous rotation servos. The servos in the
kit were HiTec 475 servos.
Q: Will there be more sensor connections available? (e.g. connection extenders)
A: There will be one daisy chained box for four touch sensors. There is the
possibility for other connection extenders being provided at a later date for
other sensors besides the touch sensors.
Q: Has the strength of the connection between the metal and Lego components been
improved? Several teams expressed concern about this after collisions that
caused the Lego components to fall off.
A: These connection points have not been altered since the demo exhibition.
(NOTE: On the robot we were shown, the connections did not seem to been weak at
Q: For the Bluetooth dongle, are there any recommendations? Are there any
dongles that are best?
A: The DLink DBT120 is recommended. In the kit there is a dongle provided.
Bluetooth dongles that don’t require the installation of additional drivers over
the Microsoft drivers are best as they cause fewer problems for the users.
Loading a driver might add complications cause problems for the robot. (NOTE:
They said Toshiba chipset dongles seemed to cause problems in testing, might
want to avoid these).
Q: Are there any problems with the Bluetooth system currently?
A: There seems to not be any problems once the link is established. The only
major problem occurs if the user unplugs the dongle during an active connection
to the NXT. To fix this remove the batteries from the NXT, reset, and reconnect
Q: Are there any there any changes to the competition format for next year?
A: Nothing too major will change; they would like to see the use of more sensors
by teams in the competition.
Q: Are there any major kit changes that will occur from between now and when the
kit is released?
A: The optical shaft encoders that are on this robot might not be the final
encoders at the time of the kits release. Also the DC & Servo motor control
units will have a redesign for esthetics, not for function.
Q: Is there a limitation for the number of “channels” for the new Bluetooth
A: No, but there is a problem when too many signals are in the same area. There
might be a tether, like for Vex, in the pits to cut down the chatter in the
Q: How much of a kit was used to make the demo robot here?
A: The robot shown here is about 2/3 of the kit planned to be provided.
Q: What is the material on the bottom of this robot, and will we able to use
this in competition?
A: This is a sheet of polycarbonate. We are hoping to provide some material like
this to the teams so that they can use it for shielding, decoration, etc. in the