2015 Kit Review Outline What’s Changed for 2015 Various Topics David Kwast April 27, 2015

What’s Changed for 2015

2015 Consumable Kit Changes Added 3/4” Foam Board Removed 1/8” PVC Sheet Added 1/8” Polycarbonate Sheet Changed 1/4” Diameter Dowel from Hardwood to Oak (higher quality) Changed Length of #10 Socket Head Screw to 1” (3/4” is still allowed) Allow Bank Wrappers on Pennies

Consumable Kit Changes Increase Length to 1’ (3/4” still okay)

2015 Consumable Kit Changes Per the Random Elimination Protocol for 2015 Removed 3/8” Plywood Removed Heavy Door Spring Removed 2.5” Hinges

Consumable Kit Elimination Items

2015 Returnable Kit Changes Removed MXL Belt Items Added HTD Belt Items Removed 9V Cortex Backup Battery Holder Removed Optional 1/16” Allen Wrench Allow VEX Competition Retention Clips on the Cortex

Returnable Kit Changes

VEX Competition Retention Clip

2015 Kit Related Rules Changes Allow Use of Video Capture on the Robot

2015 Kit Topics VEXnet Keys The feedback I have received on the new white VEXnet keys has been good in general. There have still been issues with loss of radio connection or the inability to establish a connection at all, but there has been a significant improvement from the old black VEXnet keys. Below is a list of things to consider if you are having connectivity issues:   Poor connection to main battery Trouble shooting: Jiggle wires in between the main 7.2V battery and the Cortex with the unit powered up to find intermittent contact. Notes: The old style white Molex connector common to the Cortex can have very poor retention capability (as in almost zero retention sometimes). The newer black Molex connector has much better retention. Both styles (white and black Molex connectors) become unreliable if they are plugged in and out very many times. Remind your students to only unplug the main 7.2V battery at the PowerPole connector.

Example of White Molex Connector in Cortex

2012 Kit Tips To eliminate white Molex, ask VEX for the Cortex black Molex pigtail connector or participate in the refurbishment program.

2015 Kit Topics VEXnet Keys (continued) Poor connection at USB port Trouble shooting: Jiggle the VEXnet keys with the units powered up to find intermittent contact. Notes: Taping the key in place at the Cortex can help (but not on the Joystick because tape is not allowed on the Joystick). Using the optional battery cover thumb screw on the Joystick can help (because it pushes against the key).   Radio interference from low-profile Cortex unit Trouble shooting: Try using a USB extender cable to get the VEXnet key away from the Cortex to see if there is an improvement. Notes: The VEXnet key is in a greater EMF influence on the low profile style Cortex. A USB extender cable of up to 18” is allowed per the RK list. A USB extender may also help if there is a lot of metal surrounding the Cortex/VEXnet key on the robot.

High profile Cortex with Molex to PowerPole adapter. Low profile Cortex with optional USB extension and Powerpole conversion.

2015 Kit Topics VEXnet Keys (continued) No connection at all Trouble shooting: Try re-establishing the Cortex to Joystick pairing by connecting them together with a USB cable and then retry the VEXnet keys. Try different VEXnet keys. Try updating firmware in the Cortex, Joystick and VEXnet keys. Notes: We have had good luck solving this issue by doing a firmware update on all of the components. If this doesn’t work, you probably have a bad component (or heavy RF interference).

2015 Kit Topics Cortex I don’t think we have had a single outright failure of a Cortex at my hub. Although some units have been cantankerous when it comes to up loading firmware or a user program, as in requiring more than one attempt to get the firmware/software to load. The most significant weaknesses of the earliest units have been resolved (which were as follows); low profile unit has decreased range and is more susceptible to radio interference (because VEXnet key is closer to microprocessor); white Molex connector has poor retention force with interfacing cable (Molex to PowerPole adapter in our case). Note that if you do the VEX refurbishment program, these old style units will be replaced with up-to-date units.   Cortex 9V Backup Battery The ability to use a 9V battery Cortex backup battery/holder will be eliminated for 2015 (was optional for 2014). Note that unless you are using the VEX field controller/hardware/switches (which plug into the Joysticks when teams are competing on the field), the backup battery doesn’t do anything beneficial (and can cause battery drain if used incorrectly). I would also contend that the backup battery is just a band-aid for things that can be avoided in the first place (keep your main battery well charged and address any poor connections to the main battery).

2015 Kit Topics Joystick The only failures I have heard about or experienced are sticky or stuck buttons. The units seem to be fairly robust in terms of impact damage. I have seen them dropped on hard floors on multiple occasions, and I haven’t seen them break yet.   Note that the recalibration procedure is easier with the new white VEXnet keys; no connection to the Cortex and no VEXnet key required; just turn on the Joystick and run it through the recalibration steps. Belts and Pulleys We expect better performance from the new HTD belts and pulleys. The old MXL standard is not designed to handle the torque that we are subjecting them to; belts slip and parts break. Large Motor I have received some feedback that some wear related failures have been occurring in the large motors.

2015 Kit Topics Motor Controllers We have seen a fairly high failure rate with the motor controllers at my hub. Most of the failures seem to be due to shorting out the units (sloppy wiring). So all of the failures of these units at my hub this past year were limited to just two teams (who had poor wiring - strands of exposed copper just waiting to short out), so this doesn’t seem to be a general problem (we also charged these teams for new units).   Motor Terminal Cables I highly recommended that stress relief be provided for these cables (see the “Mods” tab on the kit list spreadsheet); otherwise the wire strands will break where they run into the metal ferrule at the white terminal end. The modified cables are much more durable (also helps to prevent shorts that fry the motor controllers).

2015 Kit Topics Servos The servos tend to fail at high rate due to abuse. If the servo is used such that forced into uncommanded position or is in a state of constant dynamic oscillation, it is likely to fail. We warn our teams about this at kickoff. We charge our teams for stripped gears (usually caused by abuse), but give them a pass if the servo is electrically dead.  

2015 Kit Topics Software The utility and drivers to update the Cortex and Joystick firmware come with the easyC installation package, but they can also be downloaded separately. The utility and drivers to update the 2.0 VEXnet keys is a separate package.   Latest easyC package: http://www.intelitekdownloads.com/easyCV4/ Firmware utilities: http://www.vexrobotics.com/wiki/index.php/Software_Downloads Note that an easyC user program cannot be loaded into the Cortex if the firmware version in the Cortex is higher than what easyC was expecting. The solution is to download the latest version of easyC and then try again. Also note “connection” problems when downloading programs to the Cortex can be sometimes be solved by manually selecting the Comm Port (look at \Tools\Options\Download menu in easyC).