I Need A Simple Mechanism

Did you want a girl in a bikini that kisses the winner and presents a trophy too?

That sounds good too, but I'd probably just lose my marbles.

I don't gotta show you no stinking safety features.

That might work. Colored Christmas Scotch tape - the winner gets it, the loser gets zilch. That's not a mechanism, but it's so simple even I could make it. Course, it might not stick to a moving car. What's plan B?

I could use a lever flipped by the two cars and let the lever grab the tape. I probably could even use Velcro if I had to.

A GA. Thanks.

Read this first.

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As promised PLAN B. While safety is no feature we continue in destruction:

This system needs some space on the track (central), or in the track or under the track. If you drill some tiny holes in your wood, you need no bearings for the first 300 races. Because of the economic situation we propose 1 flag (stiff = viagra type)

It will create less jobs but will cut expenditure with a higher profit margin.

I hope this decision to change the 2 flag gig, is not too disappointing. Please don't get depressed.

I have no idea of the scale of your racing business but the flag pole can be e.g. a TIG welding rod that has to be cut and bend to specs.

The triggers can be paperclips, they come in all kind of sizes. The spring can be a modified ball point pen one.

I have not written a user manual yet or a troubleshooting sheet and the copyright is herewith free to you.

The two triggers put the flag in a pre-stressed (spring) center position. First trigger moves the flag to its track.

Have fun

Your cherry.

Although I don't understand anything you've said so far, I think you are on the winning track. Be it right or left.

Okay I'm not so sure about the "cheap" part but this is inexpensive and will remove all doubts! Forgive the lame "paint job" but I'm tired and about to sack out after I post this. Before you bite my head off it isn't a complete schematic, but if you understand electricity you'll get the main reason of what I'm emphasizing.

So if you look at the first pic you'll see each lane has an embedded micro or momentary switch. So lets say Lane 1 wins...what happens? Coil 1 is activated. If you look at the lower diagram you'll see Coil 1 has 2 contacts labeled "R-1". BEFORE the race started BOTH LEDs were lit. Once Lane 1 was the first to cross the lower set of contacts were activated. Lane 2's LED goes out and stays out, and the coil for contact A opens and prevents Lane 2 from activating Coil 2. Lane 1's light stays on and it's time to pop the cork on the champagne! Should Lane 2 be first the inverse happens.

I ain't gonna bite yer head off. Thanks for the idea. I want to find something mechanical if I can. I'll only go with that new-fangled electricity if I have to.

Cheers and get a good night's sleep.

If you go with a piece of tape or ribbon you can still get a lot of mixed results. It's a very short distance so the races could be very close, like in millimeters. If it was a ribbon and the second car was finishing with more speed it could cross the line second but still have more momentum and appear to win as it took the ribbon off the winners bumper.

In reality its just a few 12V relays, a 12V source (batteries) and a few cents for resistors and LEDs. And as to it being a kids toy, what kid doesnt dig LEDs???

But I admit the only real part that's mechanical is the micro switch.

Whatever you decide on you should post a few pic for us to admire.

A single long bar over all tacks movable in slots at both ends and spring loaded, when spring releases all tacks door will get closed, A rat catcher like trigger provide on all tracks to release the spring force. Car that hits trigger first will close the doors for all others.

Wow, talk about weird responses to what is obviously a child's game.

Girls in bikinis and electrical circuits? Come on.

With a 40" track the cars must not be very big, so I'd keep it as simple as possible. Go with the trip gates. The kids don't care about sophistication at that age. You might find a way to have the winning car knock the runner-up off the track and wreck.

Good luck.

Ooh, I like that! Just a small hydrogen rich atmosphere at the bottom and the winning car strikes a flint for the other track. Crikey, the kids'll love it!

did nobody mention firecrackers? perhaps this is going to end up on the 'crazy things parents do for their kids' thread...

Although it isn't purely mechanical, how about a "photo finish" Webcam, with a way to store the last second's worth of images as the racers cross the finish line? The right two adjacent images from this set should resolve any questions.

Yeah, that was a fall-back idea. With everybody carrying a cell-phone camera these days, they could get into that pretty easily.

This sound like the Boy Scouts "Pine Box Derby" type of racing?

If you have ever played with Mattel "Hot Wheels" when you were a kid you would remember the simple Finish Line mechanism they used to sell with their racetracks to indicate who the winner of the drag race was. Ohhh my, I'm dating myself back to the late 60's and early 70's! LOL My mom still have those cars and tracks that my brother and I used to play with....my kids, nephews and nieces all played with them too when they younger. They're probably worth small fortune now days as they're all in great shape! Still love the chromed Mustang and Barracuda I received when my Bro and I joined the Hot wheels Club back in ???1969???

May you could take a look at one and make a reasonable facsimile of one out of wood or glued together plastic parts......ie, make a modified version of it, but not copy it per Se. Not sure if the patent is still in effect for that gizmo or not. If you're not selling these you will probably be okay, but then again I'm not an attorney either...

Good luck playing with the kiddies! Wish I was there too, as the Pine Box race cars are always pretty kewl!!!! Now I play with HO railroads and HO slot-cars (the 'ole Aurora AFX cars to be exact) instead......

Yeah, that's what I'm trying to remember. All the pinewood sets use electronic timers these days. But the Mattel idea might be good if I can find one. I'll watch yard sales.

Why reinvent the "wheel"? The system you are requesting help on is almost identical to that used by Cub Scouts for their "Pine-wood Derby". A gravity track with several lanes, a parallel starting gate at the top and some kind of "first finisher" indicator at the bottom. Contact the local Cub Scout Pack and ask to see their arrangement. If your requirements are similar to theirs they may let you use it. The best thing about that would be you don't have to store it!

To find the local Cub Scout Pack, not the Boy Scout Troop, ask some 7-10 year olds who runs their pack. If that doesn't work ask their parents. If all else fails look in the telephone directory for the local Boy Scout Counsel. There usually is one every few county's, at least in the USA.

When I was involved with this in the early 80's we used three reputable individuals to "eye-ball" the finisher with the Pack Leader having the final tie-breaker authority if necessary. Being tall and of muscular build usually helped me when it came to having to make the decision. Now I have seen sophisticated optics with elap. time indicated for each vehicle. I even saw one which does a photo finish just like at the horse race tracks! Each contestant was eventually given a CD of all the races and all the finishes.

Good Luck, Old Salt

How about a couple of pieces of paper that the cars run over? They start off bent up enough that they don't touch at the center line, even though they are angled to make an arrow showing the direction of travel. After a run, it is easy to see which one is on the bottom. A little bit of fancy bending to make a very shallow cone in the middle can make the paper strips snap either up or down, to hold the reading better.

When I read the question I came up with two mouse traps mounted on a goal post over the track with a vertical rotating shaft in the centre holding four flags, draw, win, draw, lose. As the winning car trips the mousetrap (extended wire on the cheese holder), the spring hits a pin through the shaft and turns it trough 90° so that the win flag (starts positioned up stream) is rotated to over the winning lane, and the lose flag moves over the other lane. At the same time the other side of the pin is rotated out of the way so the spring tripped by the second car won't hit it. If both cars trip at the same time, the two springs hit both sides of the pin simultaneously, the shaft does not rotate, and a draw flag is shown over both lanes.

Then I read the answers, and I like the marbles better than my idea.

From a health and safety point of view. A child with a marble stuck in it's throat is a hospital job, (mine once got a marble stuck up her nostril), whereas as finger in a mousetrap is a "there, there kiss it better and don't do it again job"

You seen the "no entry/ barrier one way spikes" www.borderlifting.com

Make similar (and install the opposite direction taht the spikes goes down upon contact) and fit on finishing lines on all 5 tracks. Each spike with spring and linkage (linked to a small flag x 5 flags each with each track). So the moment any car hits its end line first the flag will come up.

thanks Griz! Some people know a good idea when they see one

Fredski your idea is good but I read somewhere he requested mechanical for kids and not electrical.

I read and comprehend quite well (most of the time). I actually took the time to consider his problem as well as the fact that he came to a group of engineers for a solution. My idea (depending on what final configuration he wants) costs about 10 bucks. It will never be wrong, there will be no ties or arguments. And as Griz suggested they should have to run twice, switching lanes for each run.

So try tape or ribbons or 2 cars hitting a gate and "almost" the same time...nothing but arguments. So yes I deviated from his original request but I gave him more than he asked for. The ribbon or tape method is weak, mine is an actual solution.

I know the electronic solution would be "better". I even have a pile of 12 V relays in the basement that I could use and still make it "Rube Goldberg". But I'm old. I remember mechanical dogs on railroad logic circuits. Humor me.

Your secret's safe with us.

I think you've hit on a simple solution.

Thanks, Lyn

Score one for the vintage flash drives used as cars.

I like your solution and it should work in any case where the cars rectangular or at least similar in shape.

The two conditions where I believe there will be a problem is:

1. The contestants are similar shape but arrive within mm of each other with the second car having slightly more mass. There is a possibility of the second car forcing it's way farther into the trap.

2. One contestant builds a car that is shaped like your jump drives and the other builds something resembling a rail (Top Fuel) dragster (very pointed front end with narrow taper to the rear) or a car shaped like a wedge (very low front tapering to higher rear). In both cases the tapered car could be the clear (visual) winner and yet the slab sided car would trip the indicator first and be shown as the winner. The wooden vane/wedge would help but not eliminate the false result.

IBGizzly,

Your right, I just had a race with an ice cube relay. Clearly the relay won, but without my high speed camera you would have though the vantage stick drive was the winner. I guess using this device you will have to have classifications in the vehicles you race.

If it is Pine wood derby style racing it will be the wheels that win the race not the nose as the wheels are standard on all cars. So the wheels will be the item triggering the mechanism.

The micro switch is a good idea but one upping that is a light reflective relay at the end of the track that turns on the winners light at the top of the track.

Break the beam and you win.

The wheels touches my no-entry barrier which triggers the flag. I win

That is NG. It's the most extremity that crosses the finish line first that wins, not the wheels. BTW, I think this is a great question; getting back to basics that sometimes eludes us.

I do like that!

This isn't the mechanism I remember, but it's so darn clever I made a mockup. It works and it's cheap and easy to make. I haven't figured out how to add flames and explosions, but we'll see.

I widened the wedge a little, added side walls on the outside, put a felt washer under the pivot to give it friction and put a crude pointer on the front. Either car now jams in the wedge, but the winner shifts the wedge, turning the pointer, before jamming. The angle is shallow enough that the loser can't backdrive it. Oh, I made the wedge solid so it couldn't deform.

Thanks a ton. That's good for 25 000 points. Save those points. I don't know what they're good for, but you never know.

For my critics-in-waiting, I really do have a set of ultrasonic rangers that will give me the velocity and position profiles all the way down. I'll break those out after everybody buys into the results of the mechanical indicators.

I'll post photos as I get these up and running. Thanks to all who helped me. I spend my days around non-engineers and I lack good people to bounce ideas off.

Right on!

Am I correct that the width/shape of the cars is fixed, or at least not an issue?

Send pix.

Not an issue. It's like racing at Pimlico; only the nose counts. I'll get pix.

Really? How about a swordfish nose?

You should probably do some testing of "photo-finishes" -- if the cars are closer than a few millimeters, you may not get an accurate indicator with the mechanical device.

We'll just call those "ties". Although, I'm told, there were more ties in horse racing after photo finishes were added.

Excellent, we look forward to hearing from you about how your racing track it turns out.

I thought your idea pretty clever, and TVP45 has clearly identified yours as a GA.

So, I vote accordingly. Well done!

Thanks, Doorman

Very Good and creative. GA.

Thanks, rakest

Give me your address. If you don't make it, I will come to kill you. My in-box is getting 5 incoming messages by the hour.

its the cops, at the in box Mr. killer

When I was young I recall my matchbox cars had a mechanical device to show which one was the winner. It looked like a single flag on a pole which sat in the middle between both tracks. The flag was hinged so it could fall left or right onto either track. Holding up the pole on both tracks was a lever. The first car to pass and press the lever would cause the pole to fall onto the track of the car that won.

I found a picture of what I was trying to remember, not quite what I recall, but this is what I was trying to think of.

http://2.bp.blogspot.com/_BXiLAmoEpMI/TPR7YPd3diI/AAAAAAAAHjg/9Oox4U6gzjY/s1600/Pinks%2B2.jpg

The picture in my first post is the one I remember but I found a slightly different design on ebay, although the principle looks to be the same.

Here is the link for the ebay search on "matchbox finish line" for as long as it works.

http://shop.ebay.com/i.html?_nkw=matchbox+finish+line&_sacat=0&_odkw=finish+line&_osacat=0&_trksid=p3286.c0.m270.l1313

Thanks. That's similar, though prettier, to what I had decided on before dkriley greatly simplified things.

It wasn't fancy, but we had a finish line that worked well for our matchbox cars. A flag with a central pivot point was held vertically between two flexible plastic pegs. When a car would cross the finish line, it would push back the peg allowing the flag to fall. To make sure that the flag fell the correct direction, the pegs exerted a force from the side that would force the flag to the side where the peg had been disturbed.

The following video shows what we had, but the video quality is poor.

http://www.youtube.com/watch?v=kR8beTLccR4

If needed, I could produce a sketch to try to detail this device a little better than in the video.

I also see that Sears or Kmart may have a track with a functional finish line.

http://www.sears.com/shc/s/p_10153_12605_004W730427110002P?i_cntr=1312989194269

I also found this post for a pinewood derby finish line.

http://www.uchobby.com/index.php/2007/05/21/pinewood-derby-finish-line-detector/

We all had Hotwheels when I was a kid and used these:

http://www.youtube.com/watch?v=kR8beTLccR4

*****

Opps...I should have read all the way down....