August 2010 Technical Topicsfor Teams
SAFETY FIRST Safety glasses (Team supplied) Hearing protection “ Dust mask “ Buddy system Keep work area clean Supervise students at all times Read your power tools owner’s manual
Use only the parts supplied in the Returnables and Consumables kits to build the robot Items that are purely decorative such as paint, lights, decals, etc, may be applied to the robot, but not to Return Kit parts The robot must fit into a two foot cube and cannot weigh over 24 pounds. The robot may expand after it exits the start box You must use the supplied batteries and chargers The robots must be VEX Cortex controlled Basic Information
Basic Information Returnables kit must be returned at the conclusion of the competition unless the kit will be purchased Do not modify or paint returnable kit parts except for servo horns and the toothed belt segment All robots will be inspected for compliance with rules before the contest. Robots may be inspected at any time a judge suspects that a robot is out-of-compliance
Batteries • Two 7.2 Volt, 3000 mAhr NiMH chargeable batteries • Six 1.2 Volt, 800mAhr NiMH chargeable AAA cells • One standard 9 Volt battery
Manage your batteries carefully! Turn power off when robot is not running Recharge batteries when robot performance first indicates a drop in power. Minimize number of charge cycles Team-owned batteries are not allowed on the field on game day Batteries
Battery Chargers Chargers are included in the return kit Read charger instructions and follow carefully! Battery will become warm during a charge If a battery becomes hot during a charge, disconnect from charger immediately! Batteries can explode!
Cortex Microprocessor Battery Charger • Two blue 7.2 Volt batteries are included in the Return kit • Only one battery can be connected to the robot • Both batteries may be charged at the same time • the larger of the two power supplies works with the blue charger. • The 9 volt battery may be used for backup power via a special port on the Controller
VEXnet Joystick Battery Charger • Battery charger for six re-chargeable AAA cells that power the Joystick • Do not try to charge standard AAA cells • The AAA cells are installed inside the Joystick unit and accessed with a small Phillips screwdriver • Only the smaller of the two power supplies works with the AAA cell charger
VEXnet Joystick • Joystick communicates with Cortex controller via wireless 802-11g • Two X/Y joysticks plus 12 programmable buttons • Ports on the back are: - Partner – phone cord to another Joystick shares control (buddy system) - Program – programming cable from PC USB port - Competition - ? • On/Off power switch Top view 802.11 Adapter Back-side view
Cortex M3 VEXnet Controller 802.11 Adapter Two UART (data) ports One 12C (sensor) port 8 Analog ports 12 Digital I/O ports 10 motor/servo ports • 2 built-in speed controllers • 2 external speed controllers On/Off Switch Backup power port (9V battery) Rx 2 Rx1 7.2 V battery port
Cortex Controller Wiring Plan Black, - Gnd Red, +5 White, control/signal - Gnd + 5 V Rx (clock for 12C Tx (Data for 12C Black, - Gnd Red, + White, Control/Signal Two Wire Black – Red +
VEX Control System Small motor Switch Large motor Servos Speed controllers Large motor
Install VEX Cortex with two screws not too tightly Provide easy access to VEX Cortex power switch and battery The battery must be secured to the robot without applying tape or adhesive to the battery Wire Red to Red (+) and Black to Black (-) Recommendations
VEX Programming System • EasyC or RobotC software must be installed on a laptop or PC. • Programming may be downloaded to the VEX controller without disconnecting the controller from peripheral devices
Servos • Connect to the VEX Controller • Used to control microswitches, or drive mechanisms (like grippers, releases, etc.) • Do not open or otherwise modify servos! • You can change/modify the horns (wheels).
DC Motors • Do not disassemble or modify motors • Connections to motors should be made with crimped terminals from the consumables kit • Reverse power connections to reverse direction of rotation
Recommended Tool List • Emerald Coast BEST Tool Kit Recommendations *Tool set includes measuring tape, screw drivers, sockets, wrenches, pliers, allen wrenches, hammer, etc. Tool source is Harbor Freight. Equivalent tools may be purchased from other sources.