Friday, January 16, 2015

Robotic Desk Racers - Part Three

A novel experiment this session.  I made up a work list.  Specific tasks to accomplish with my estimate of how many kids could effectively work on each one.  I let them sign up for what they wanted to do.  Sixth graders first, then seventh, then eight.  Within a class it was alphabetical order of sign up.  Next week the grades will be reversed and the kids will sign up in anti-alphabetical order.  It seemed to work out pretty well.

As always, we could have put an extra half hour to good use.

Racer A needed some reinforcement.  Here the kids are "under the hood".

I have to say, they have done a good job on this one.  The wiring issues have been resolved and it is now fully operational.  The test drive they took over the anticipated "Grand Prix" course through the hallways came in at just under 1 minute 30 seconds.  That is about what I was aiming for so I do not think we will have to bump the power up to 24 volts.

Most of the effort today was on Racer B, and we were fairly close to having it operational too.  The motor/gearbox/wheel/mount units ready to attach:

Liberal quantities of wood glue and drywall screws have them securely on, and the desk attached to the platform.

We need to string wire from the drive units to the speed controllers, add a battery mount and a main power switch.  This is at most one hour of work assuming nothing gets broken.  Here we have units A and B next to each other...

Unit A on the right certainly looks bigger and meaner, but I think they will be competitive for speed. B has, I think, gearboxes designed for 6 volts so running them at 12 will be a 100% over volt and should compensate for the roughly 50% smaller wheel diameter.  B is more fragile, so it will be important to not let lunk heads try and hop on for a ride during the race!

Unit C will be harder, but we have five sessions left, so I think it will be possible if I fab a couple of custom adapters for the wheels.  B and C do not have any spare gearboxes, so they are on the NSP engineering program.  No Spare Parts means any serious mishap is fatal.

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