Search found 20 matches

by ironband
Sun Jan 14, 2018 12:28 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - relationship between COM and drift
Replies: 10
Views: 193

Re: Rail Riding - relationship between COM and drift

It is a nice track. I spent the better part of yesterday with our cubmaster extending the stopping area - over the years the original foam rubber compacted in the box, and previous years' attempts at adding grip tape, sandpaper, and who-knows-what else on top have been ineffective. We built an exten...
by ironband
Sat Jan 13, 2018 9:59 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - relationship between COM and drift
Replies: 10
Views: 193

Re: Rail Riding - relationship between COM and drift

Ah, that makes sense - thanks for the clarification! We're on a wood track (20 year old Piantadosi, but in pretty good shape).

My daughter's name is Emma - so we'll be rooting for you!

Andre
by ironband
Sat Jan 13, 2018 7:16 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - relationship between COM and drift
Replies: 10
Views: 193

Re: Rail Riding - relationship between COM and drift

Speedster wrote:
Sat Jan 13, 2018 7:06 am
Always, and I mean Always, the car will drift to somewhere close to 36".
Thanks for the info Speedster - but do you mean 36", as in 3 feet of drift over 4 feet of running? My tuning board isn't that wide...Is this a typo?

Regards,

Andre
by ironband
Fri Jan 12, 2018 8:43 pm
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - relationship between COM and drift
Replies: 10
Views: 193

Re: Rail Riding - relationship between COM and drift

As you make the COG more aggressive, you need to increase the drift so that there is more pressure on the guide rail to help keep the car going straight. (since there is less pressure on the track itself) OK, I can get behind that. So if at 1.5" we had success with 2" of drift over 4 feet, do you h...
by ironband
Fri Jan 12, 2018 12:48 am
Forum: Car & Semi-Truck Construction
Topic: Rail Riding Question - indenting RR wheel
Replies: 9
Views: 259

Re: Rail Riding Question - indenting RR wheel

Last year we had a similar situation - 2.5 deg rear axles, 1.5 deg front axle, and no thinning of the front end, though that was just due to poor planning rather than rules concerns. We solved the problem by gapping the rear wheels with a credit card (about 0.030") and gapping the fdw with the kit b...
by ironband
Fri Jan 12, 2018 12:40 am
Forum: Car & Semi-Truck Construction
Topic: Rail Riding - relationship between COM and drift
Replies: 10
Views: 193

Rail Riding - relationship between COM and drift

Hi all, 'Tis the season! And my cub and I are hard at work on our cars for next weekend's pinewood derby. Last year he wound up with a 1.5" COM on an extended wheelbase 3 wheel rail rider set to about 2" of drift over 4 feet. Racing on a wood track in pretty good condition. He took first in the pack...
by ironband
Sat Mar 18, 2017 9:15 am
Forum: Electronics
Topic: Lasers as better finish-line emitters?
Replies: 3
Views: 771

Re: Lasers as better finish-line emitters?

I think part of the appeal of infrared or visible light is that it doesn't have to be *precisely* aligned, just aligned enough to get enough light in the hole to keep the phototransistor activated. With the laser approach, you would need to keep precise alignment throughout the race. I'm not saying ...
by ironband
Sat Mar 11, 2017 11:01 pm
Forum: Electronics
Topic: Raspberry Pi based Instant Replay system
Replies: 2
Views: 797

Re: Raspberry Pi based Instant Replay system

I like the view from the end of the track, looking up towards the start line. I like to see the whole drama of the race, not just the finish, as some cars get a fast start but then get passed in the flat. I like the idea of that, but it makes it hard to see the finish clearly if you aren't a little...
by ironband
Mon Mar 06, 2017 8:37 pm
Forum: Electronics
Topic: Raspberry Pi based Instant Replay system
Replies: 2
Views: 797

Raspberry Pi based Instant Replay system

Hi all, As some of you know, I've been working on retrofitting my Microwizard P2XL with an Arduino timer for serial communication as well as timing. As an adjunct to that project, I picked up an old Raspberry Pi B+ as well as a V2 PiCamera, and thought it would be cool to interface them with the Ard...
by ironband
Thu Mar 02, 2017 12:08 pm
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

http://www.youtube.com/watch?v=P9TFidUFHKw As promised - electronics and code are working well! Unfortunately the camera module for my Raspberry Pi broke when I tried to put it in an ill-fitting case, so I'm waiting for a new one to come in before I do development on the instant replay. In the mean...
by ironband
Tue Feb 28, 2017 2:43 pm
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

Update: Almost done! I need to mount stuff in a project box and set up a long cable for the start gate switch, but everything is working! Here I have soldered leads from an old ethernet cable onto the header in the finish line: http://i517.photobucket.com/albums/u332/ironband/20170224_123530_zpsmorw...
by ironband
Thu Feb 23, 2017 10:29 pm
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

Happy to report that no smoke was generated in the first successful test: http://www.youtube.com/watch?v=1R_juWSSQjs I loosely attached some leads to the three phototransistor pins (3,5,7) and had a successful test. I used 1kOhm resistors to ensure that the slight overvoltage wouldn't be an issue. S...
by ironband
Thu Feb 23, 2017 11:11 am
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

OK, update - I got the finish line from my cubmaster and tore into it last night. The key is this ribbon connector: http://i517.photobucket.com/albums/u332/ironband/29237212-34ab-43a8-9e54-5884ed126942_zpsl9i6vayu.jpg After tracing the circuit through, the pin-out is (starting from upper left) 1 - u...
by ironband
Thu Feb 16, 2017 10:55 pm
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

I Love Derby Talk, I Love the generous people on Derby Talk, I think Derby Talk is the Greatest Site on the Internet for Pinewood Derby Information. Even though I'm new here, I wholeheartedly agree with this sentiment. This site was a big help in getting my family "on the podium" after years in Cub...
by ironband
Thu Feb 16, 2017 5:58 pm
Forum: Electronics
Topic: Arduino upgrade of Microwizard P2XL
Replies: 15
Views: 1666

Re: Arduino upgrade of Microwizard P2XL

This is correct. The Arduino Uno can take a voltage source between 7 and 12V. Just be sure you're running through the Vin pin, and not the 5v pin. I get that much - I'm talking about tapping the photo-transistor circuits to the Arduino digital inputs to detect when a lane finish occurs. I'm hoping ...