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Sharon Youth Robotics Association Vex Robotics Kit |
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Link to the New Vex Components page, including Vex Robotics Programming Kit. Link to the New VexLabs structural components. A great Vex robot drive speed chart on the VexLabs Mechanical Components forum. Mild steel structural components are somewhat similar to building with an Erector set, with more types of beams than previous. Bolts have hex heads, and are turned with hex drivers/Allen wrenches (the stainless steel hardware available directly from IFI is substantially stronger, with the hex heads much less likely to strip). Wheels have varied treads and sizes, no more soft foam that can't actually support the weight of the robot without deforming. Axles are still square, which simplifies wheel insertion and helps with shaft collars, and the Delrin bearing blocks let them turn freely. The key tools are included - two Allen wrenches for the bolts and shaft collars, and a open-end wrench for the nuts. The microcontroller has connections for two radio control receivers (now a single cable for each), and connections for up to 8 motors and/or servos. There are 16 analog/digital I/O ports, and the default software uses jumpers placed there to control drive and limit switch functionality. Interrupt input are still present, but solenoid I/O has been removed. The power connector now accepts the standard 7.2v battery pack jack, without requiring a cable adapter. The radio control subsystem now is bundled with the system, and it is a top quality system. A custom-housed Futaba system, it includes a 75Mhz 6-channel digital transmitter (dual joysticks and dual button pairs) and a receiver that requires just one cable connection. With an LCD display, a large amount of customizing is possible on the transmitter. For example, two transmitters can be configured on the same frequency to allow one driver to control chassis movement, and another driver to control other mechanisms. The transmitter can also be hard tethered to the controller with a phone handset cable. Additional crystal sets are available from Radio Shack at very reasonable cost. Three motors and one servo come with the kit, with digital proportional control (for speed and positioning respectively). The mounting is more secure, and an included clutch mechanism will hopefully reduce gear breakage. Limit switches and bumper switches come with the kit, but many more servos will be available in the fall of 2005. Functions such as a shaft encoding (rotation), light sensing, range sensing, etc. will be available, as will be a programming environment package including both C and a visual environment on the idea of LEGO Mindstorms coding. Gears have been added to the development environment, but sprockets and chains have been removed. These will be restored as add-on kits in the fall.
The above diagrams are reproduces here with permission from Radio Shack, and show the parts and quantities that are part of the Vex Robotics Development Syste. The Inventors Guide helps to teach the functionality of the full kit, and includes sections on: Structure Subsystem (building with the metal parts, including concepts like center of gravity) Motion Subsystem (building with motors, gears, axles and wheels) Power Subsystem (providing battery power) Sensor Subsystem (using sensor input, for now limited to switches) Control Subsystem (using the Radio Control system) Logic Subsystem (using the Vex microcontroller) Programming Subsystem (not ready at this time, to be based on C and a visual interface) Reference (Safety, Glossary, Challenges, Inventory, Control Configs & Transmitter Menus) and includes suggested paths for novice and experienced robot designers, as well as instructions for building the demonstration robot, squarebot. Batteries are not included. Battery holders for both the robot and the transmitter are included (suitable for individual NiCad cells), and battery packs and chargers are available from Radio Shack.
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Sharon Team Unlimited FTC website Last modified: 07/26/08 All Rights Reserved © 2007 by Team Unlimited |