EMF Pinewood Derby: A Practical Physics Project

[Windadct]

Glad to hear things smoothed out with the team.

By the way I like the "switching" scheme you used, good use of logic.

I was suspicious of the "shoes" and not having too much friction. (Pinewood derby cars are all about friction (1) and Weight distribution (2) ... )

One way to reduce the issues with the brushes / shoes is to use relays, use them to energize relays, and the relays to energize the load ( coils) - however in a loose assembly and little time - the inconsistent connections of the shoes / brushes may make the relays chatter, and possibly make the issue worse. But since the load (current) feeding the relays is less than the coils - you should be able to reduce the friction, etc.

A good project since there are a good number of subtle issues to learn...

Oh -- at the end - post a video...

 

[Stinson]

Presentation day was yesterday. It worked and we scored a 2! Professor graded it himself saying he thought it was excellent and insinuated it may have been a 3 except the lack of teamwork. Easily put 100 hours into this thing over the last 10 days, so after the presentation I just skipped my next class (test debrief) and went to bed. Slept solid an uninterrupted for 20 hours until my alarm warned of this morning's classes. All in all it was a success and another judge invited us to a second presentation Friday which will be a high school field trip.

The group to our left looked neat on paper but the guy who had the physical representation didn't wake up to bring it in. Ow. He texted them half an hour after judging started to say he just woke up and the judges kept saying they would circle back around but he never made it. The group on the other side had electromagnets in the upper portion a clear acrylic cylinder with a piston head of permanent magnets in the tub below it. It was supposed to move up and down similar to a car engine and turn a crank shaft attached to a fan but didn't work unfortunately. I didn't get a chance to walk the room and check the others out, which I was really looking forward to.

Got some other stuff which needs attention at the moment but I'll hook it all back up and film it later this afternoon. Thanks for all your help!

 

[sophiecentaur]

Excellent, excellent, excellent! Congratulations; you deserve a massive round of applause for your stickability.
We will hear from you again, I am sure.
Don't forget to document what you have done, with plenty of pictures and writing in a file. It will impress someone when you apply for an academic course or a job. A transcript of this thread could also be good for you to record; it will show how you are capable of getting what you want out of people!

 

[Stinson]

Just letting you know I haven't forgotten this thread. Physically broke the car a week or so ago during trasnport. Tried to hot glue it back together but wasn't really successful. All the structurally unwise prototype sawing compounded together and it snapped in half where the magnet would go. Making a new car (and going all out to make it look great, as it will probably be simi-permenatly displayed in my house somewhere) which is why I haven't posted a video. Exams are looming, the follow-up project for this class is underway, and I'm just generally busy. I haven't forgotten about the video though and I will make it as soon as I finish this car. I'm using bondo to widen the classic pinewood derby block so the wheels will be covered like a real life car - and going for a corvette look. I go out to the garage and do some sculpting in-between studies as a fun active break and hope to produce a somewhat well done Youtube video, which I will share here when complete. Thanks again for all your help and support.