Poor Man's Multi-Lane Electronic Finish Line with Times

vantage509 Saturday, 2/8/2014

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Upon setting out to build a simple track for my 3yo son and I to play on, I was discouraged to find how difficult it is to get/make either a slim-featured electronic or even simple mechanical finish line. After quite a while searching the web and viewing multiple different finish line options, I finally had a bit of an epiphany. I'll use my experience with online coding languages and make my own darn finish line!

At this point I have a promising proof-of-concept and am a third of the way to a working prototype (I don't even have a track yet!). I'm hoping to do a full walk-through on how to do this as I refine the process. In the meantime, here's a hint to get your collective taste buds salivating. I'm a complete novice at any lower level electrical work, so fear not, I will create a SIMPLE project!




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redlinederby 2/9/14
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When I tried to make my electronic finish line I used an Arduino board and some sensors, then it would hook into the laptop to post results to software I made. Kinda worked but had some issues with the sensors, never really gave it a second try but I should.

Looking forward to see what you come up with. If you crack the case you'll be a hero

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Preacher 2/9/14

Cool keep the information flowing...I personally like the DYI stuff!


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model40fan 2/9/14

sorry i posted on the wrong topic

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Keef921 2/9/14

Just a few thoughts..

I made a finish line for my slotcar track using a similar method on the video except I used a USB gamepad and connected LDRs across two of the buttons. It worked most of the time but seemed to caused the PC to freeze occasionally, I'm not sure why.

It may be easier to use a cheap laptop with a Parallel port and connect your sensors directly to the port, it cuts out the USB circuitry. This is what I now use (for slot cars with free UR3.0 software) but there is no reason why it couldn't be used on a Hot Wheels drag track.

My current plan for a Hot wheels finish line is to use a cheap 'Quiz Buzzer' electronic kit I have bought and connect sensors across the buttons, hopefully this will give me a cheap and portable option. When I get round to I will post back if it works.


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redlinederby 2/9/14
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I think I'm missing something...I watched the video but don't see how that relates to the finish line. He's making a push pedal, that I see. So is that used as the sensor?

@Keefe - Do you have a photo of the quiz buzzer you cannibalized? That's a good idea but never thought to use one of those. Where do you find them, teacher supply store?

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Milton-Fox 2/9/14

I think that is just one component of the system he is designing. Reminds me of the foot release for the drag tracks.

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Keef921 2/10/14

@Keefe - Do you have a photo of the quiz buzzer you cannibalized? That's a good idea but never thought to use one of those. Where do you find them, teacher supply store?

The kit I have is the Velleman MK133, I got mine from Ebay but there is a few on US Ebay


I am probably going to use this one thought....


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jojo 2/12/14

Probably an easy find for now since the threads are just a line or two apart in the forum, but for future purposes, here is my solution for a cheap-ish electronic finish line timer using an Arduino --> viewtopic.php?f=3&t=1681

Of particular interest for an ultra-cheap build would be the ability to use the same architecture as I did but without the LED displays and/or using parts you might already have around.

Also, for something to consider since I was in a very similar situation as you (one of the users being a 3 year old), I think the ability for the timer to operate as a "stand alone" unit which my son (or better yet Mom) can simply plug in and use without firing up a PC or having any idea how it all works is an important design factor.

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vantage509 2/13/14

@jojo: That's a fantastic solution using the Arduino. I did see your post and it helped inspire what I am ultimately creating.

Everyone else! Below is a link to the "software" I created. It's just a simple JavaScript web page that allows you to map keyboard keys to lanes (and a start gate!). All you need is an old keyboard, some switches/triggers and any computer. I'll work on creating a step-by-step as I get to the hardware piece.


Please play with the software (no need to tear a keyboard apart yet) and let me know of any problems or suggestions.

Quick Start Instructions:
- Defaults to 10 lanes, each mapped to the corresponding number key at the top of a keyboard
- Start is mapped to the ` (tick) key to the left of the 1 key
- With the software's browser window active, press the ` (tick) key to "Start" the race
- Randomly press the number keys to simulate each lane crossing the finish line
- When the race is "over" you can press the "Save & Reset" button and you're ready for the next race

Changing Settings:
- Some lane buttons not working? Have more or fewer lanes? No problem! Click the "Set Lane Buttons" link at the top right
- Set the number of lanes (1 - 99) and click the "Save Changes" button
- To change a lane's key code (two or three digit number that represents each key on the keyboard) simply click on the field and press the appropriate key
- Update all lane keys, click the "Save Changes" button and you're ready to go
- Click the "Get Racing!" link at the top right of the page and you're right back to running races

For a REALLY simple trial, stand a keyboard up at your finish line, program the lanes by running a beater car down them, then do a race! You'll have to manually trigger the Start key when starting (maybe a second keyboard?), but you'll get the idea.

Looking forward to getting my first track created!


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jojo 2/13/14

Generally worked OK for me except that it wouldn't resister additional key presses if particular other combinations were held down. I would guess this wouldn't be a "normal" use case, but hey, you asked for someone to try and break it

I suppose, though, that depending upon how the sensors are pressed as the cars pass the finish line, in a close race maybe you could get enough cars close enough together for this to be an issue?

Have you started on the track construction yet? In hindsight I probably could have guessed this, but my youngest two are generally just as happy (or more so) to take a bucket of cars to the top of the track and watch them all pile up at the finish as they are to see those lane times flash by

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model40fan 2/13/14

Bravo for the "bucket boys" !

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vantage509 2/13/14

Bravo for the "bucket boys"!

Oh, I'm sure my kids will be the same (for a few years, at least). But I'm looking forward to using this track myself with friends and the various youth groups I'm involved with. They'll love having times and some competition!


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