More Tips & Tricks from Todd: PVC Rollers & Motors

Posted on February 2, 2012 by tmw2010

Recently, Todd Lovelace, mentor of Team Resistance was asked the following questions:

1) I’m sure you guys have tested the PVC rollers/poly cord on these new balls. The balls are a bit heavier than in the past, but does that system still work? 

2) What motors have you used for the rollers? I think we’re sticking with 4 CIMs on drive, the 2 fisher price (possibly 2 FP and 2 banebots on the turret). Would a L/R window motor or a banebot give those rollers enough speed to handle these heavier balls? 

This was Todd’s entertaining and highly useful reply:

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Polycord will have a great capability to carry these balls. Be sure to stagger the rollers that the cord runs on to keep from trying to squeeze the balls while carrying them.

We are also reserving the CIMS for brute force with great reliability. We have not chosen the rest of the motors yet.

You will want to size the motor/gearbox speed on the conveyor so that the linear surface speed is the same as the circumferential surface speed (Pi*D of the roller x roller RPM) in feet per minute…ie, the surface speed of the roller in feet per minute will be the same as the conveyor cord speed and the ball-thru-the-machine-speed. The window motors are very slow with lots of torque, you will likely want something faster with less torque.

The floor pick-up roller circumferential speed needs to be about 20% higher than your top robot floor speed in feet per second to be sure you snatch the ball into the machine before it has a chance to bounce off your pick-up roller.

 

Note the criss-cross belting for roller direction reversing…….


Don’t let this happen to you.

The worst team member ever……and what an annoying sweatshirt.

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Got more questions for Todd? Drop him a line at T.Lovelace@comcast.net.   19 more build days to go!

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FRC Guest Column: Where to Start

Posted on January 3, 2012 by tmw2010

Team Resistance

Team Resistance has been actively participating in the FIRST robotics competition for the last fifteen years. This team focuses in areas such as fabrication, 3D Modeling, AutoCAD, and web design. The following is adapted from the reply of mentor Todd Lovelace – “Chief Geek, TEAM RESISTANCE aka “the Trailing Edge of Technology”" -  to a rookie team seeking a veteran “buddy.”  We thought it was chock full of great advice and share it here for veterans and rookies alike to enjoy and from which to hopefully benefit!

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Where to start?   You’ve already done it – you called on an elder team!   FIRST Teams always look forward to an opportunity to mentor and boot up new teams. To make things easier, let me ask a million questions to address and get some answered.

Are you signed up for a Regional Competition yet?  The Orlando Regional-  All the kool kids (us’ns!) will be at Orlando and it’s one of the toughest, coolest places to compete. We’ll be close by if you have an emergency. The kids will get to see the some of very best robots in the FIRST organization there.

Next step - Find out what’s about to happen!  It gets very wild very fast – starting at the Kickoff meeting on Sat morning, Jan 7, 2012.  The 2012 game (game? task, torture) will be announced via NASA TV  mid morning on Sat, Jan 7.      To minimize your stress/cost I suggest that your team join us at the JEA Customer Center auditorium for the NASA TV Kickoff Broadcast.  We can get together an hour or so early for snacks and to help get your kids and adults up to speed.

Are you signed up to attend a remote kick-off (Melbourne? Orlando?)  Do you have plans to pick up your Kit of Parts (saves big $$$)?  Let FIRST ship the very heavy KoP to Melbourne. Send one adult to  pick it up and watch the same remote kickoff there.  We’ll send two of our adult mentors down to pick up the kit.  Maybe we can group up to save some bucks.

Huge tip: Anything you can do in the weeks between now and Kickoff will pay back in diamonds.

Tools and equipment:

  • If you have access to a mill and lathe you’re ahead of many rookies. They’re not absolutely necessary, but very helpful.
  • Hand tools and small power tools are a must.
  • Cordless drills are awesome.
  • One of the best things money will buy, if the school doesn’t have one, is a Harbor Freight cheapo horizontal bandsaw.  Have (a local manufacturer) make your saw blades.
  • A BIG vice mounted on a sturdy table is one of your best friends.
  • Don’t forget a collection of sharp, new files. (best brand “Nicholson”).
  • And a Metric and ‘Merrican tap and die set.
  • “Tap Magic” lubricant for tapping threads without breaking expensive taps (I have a fresh case of cans, come get one!).
  • And a full letter-decimal-fractional drill index……….and……
  • Any aluminum round, square, flat, or sheet stock is available from a number of online hobby or “drops” retailers. We use rectangular and square tubing for structure…but you will be able to build a very serviceable robot “traction platform” from the kit ‘o parts that they provide. Look at last year’s kit of parts to get a feel for what is likely going to be included.  Most places only sell 10′ and 24′ long sticks of metal stock. We have a large stock of “junk” aluminum stock from 15 years of playing here so ask what we might have before you make a purchase.
  • Get some additional #12 red and black wire. Teach someone to reliably crimp electrical connectors.  Teach someone to solder properly. Go to last year’s robot manual and learn how to hookup the electrical power circuits that the robot controller controls. (Big current, big wires stuff).   (We can help here!)
Organization
  • See and learn the required robot power hook-up 
  • Find someone(s) who has done some programming to be the robot control system leader (student or adult).  Download the info on the robot control system (National Instruments C-Rio controller) and get them moving to familiarize themselves with the system components, how to hook it up, how to download to the robot from the PC, familiarize yourself with the basics.  see http://www.usfirst.org/roboticsprograms/frc/2011-frc-kit-of-parts  “Control System” - … If anything is gonna be a weak spot on a rookie team, programming is gonna be it.
  • Find SEVERAL motivated technical HANDS ON adults to assist you or you’ll go NUTS!  They don’t have to be engineers…..the best kind are the guys/gals that motorcycle race, hot-rod, restore cars/bikes/boats, build dog boxes, – the ones with a good feel for building mechanical stuff. My lead designer for the robot is a garage door installer. Raines HS’s original robotics mentor was a circle track racer gone bad……
  • Find a mom/dad who will volunteer to do your travel arrangements.  Do it now. Have  them start looking for rooms ASAP after Jan 1.
  • Determine who will be working on what ASAP.
  • Set up a shop schedule.  Fer instance, we work four week-nights  (M-Th 5:30 to 9:30) and two shifts on Sat and Sun (1-5 and 5:30 to 9:30).
  • Have someone responsible for snacks each work session and make the kids take turns bringing drinks and goodies. (We’re a Union Shop here so we have an Official Union Break complete with a siren to announce quitting time). (I’m not kidding :) )
  • Don’t be afraid to call for assistance! Florida FIRST can help connect newbies with veteran teams and resources and help answer questions as needed. Many veteran teams are eager to help !

Everything you can absorb, organize, delegate, obtain, set up, learn between now and New Years will surely help ease the strain after the 7th.

Todd Lovelace, Chief Geek

TEAM RESISTANCE

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