Race line finish sensor

Projects General Guidance
1

Hi all,

First I want to say thanks for reading and helping out. I am a noob at this but feel this should be a doable project for me.

So I have been asked by a friend to look into this for them. They do snowmobile drag races 1on1 and are looking for a way to tell who the winner is outside of judges. We thought for awhile and thought that the safety garage door sensors would be perfect... or that concept.. we would have two senders and two receivers one for each lane. Then the first one to break the line a light or trip the sensor, would turn a light on their lane. I had some concerns about making sure both lights didn't turn on in each race. Only the first lane to trip the sensor the light should go on. Then it would reset after a delay of X seconds and it would be ready for the next race...

So doing some research I found that Arduino might be my best bet because I can actually code for what I want to happen and have future capability to expand if needed.. For example if input 1 (lane 1) goes from high to low first then turn on output 1 light (lane 1)and shut off and keep off output 2 (lane 2) all for 20 seconds or a manual reset....

My question(s) are:

  1. The sensors off of a garage door, do you know if they are regular sensors and can just be used alone or do I still have to incorpoate the garage door's circuitboard.

  2. As said I am a complete noob, any advice would be helpful, but it looks like I should be able to create the two "sensor lines" for two different inputs and code for the outputs?.?. If I am going about this wrong please let me know.

I am only asking for any advice and to confirm I can use those garage sensors by themselves with a 555 timer (for the pulse needed on most) or if there is a better way/easier way. Please keep in mind the lanes at around 10 ft or more each. So any or sender/receiver would have to reach that far.

Again thanks for the help I look forward to any response. ( I did check the forums and felt like this should be its own topic, sorry if it is duplicated!)

2

A sensor that works in depth may trigger ahead of the finish line.

You could shallow-bury metal detectors at the line and be really close.

Arduino is more than fast enough if your code does not have parts that block the rest from executing quickly. That is a programming lesson to learn, how to make multiple things (run two sensors and lights) "at the same time".

Suppose you sat at a desk with two switches with a light over each well apart in front of you and your task was to immediately switch either switch when its light came on.

Would you watch just one light while holding the switch, ready to get that one right? Of course not but what beginners start with is code that works like that.

Here is one good tutorial to get that lesson: Gammon Forum : Electronics : Microprocessors : How to do multiple things at once ... like cook bacon and eggs

I recommend going through more than one tutorial/thread on the subject. It is key to automating, which is what your project wants to do. You can come out with much more.

Where are you that Skidoos are a regular thing? I have an uncle who used to hold jump records in Maine.

PS, I did some calculations. 162KPH moves 45mm per millisecond. That is the kind of scale you should be able to measure on though I'm not sure how fast a metal detector circuit works.

3

Hi thanks for the quick reply,

Yea that's what I planned on doing, doing things in steps and learning on the way.

I guess the real questions I had were if any one used the garage door sensors by themselves?? Or do they need the garage door circuit board due to something proprietary in the sensors and garage door opener board..

If someone used this before with just the sensors it would save me a few days testing and playing around with it.

I am in Michigan, but the sled race on a grass track in summer and fall and snow in winter.

4

a photo finsh should be the easiest to do.
in a car race, any part of any car that crosses the line makes that car the winner. in your sport, the finish line could e 10 meters wide. so any part of that could be the place where a snowmobile could cross.

put a laser sensor about 10 meters before the line, have it start a high speed camera.

post the video to a website for everyone could see it.

5

Hi,
Often Infrared Beam sensors are used for this.

Some have the transmitter section run on 5 Volts so no other electronics needed and no connection to the Arduino on that end of the finish line. They are "light Beam" but fairly insensitive to visible light as long as you shield them a little.

Example HERE:

6

Lodgingsensor:
I guess the real questions I had were if any one used the garage door sensors by themselves?? Or do they need the garage door circuit board due to something proprietary in the sensors and garage door opener board..

If someone used this before with just the sensors it would save me a few days testing and playing around with it.

I am in Michigan, but the sled race on a grass track in summer and fall and snow in winter.

I don't know what garage doors use but I can guess, an ultrasonic sensor you can get for about $2 and get running using existing code. To detect they take a few milliseconds to many depending on range and temperature (sound is slower in colder air)

v = 331m/s + 0.6m/s/C * T ....... given normal air pressure and humidity which are small factors.

331 m/s (1086 ft/s) at freezing, 343 m/s (1125 ft/s) at 20 C (68 F).

Where you put the sensor makes a difference.

Beam breaks are about instant by compare but can be falsed by snow, rain, splashed gunk, flying bugs, etc.

Beam reflects are also subject to stuff in the air but offer more placement positions.

Electric/capacitance and magnetic sensors work in most environments and can be near instant to milliseconds (snowmobile might move a whole foot, maybe two between detects at over 100MPH) slow for capacitive sensing.

If the snowmobiles can have side-pointing lights (left one points left, right points right) masked to make flat up&down light-wings then apart from crud in the air, those can sense within inches.

If you can get a high school physics teacher involved, you may get even more solutions.

All of this probably costs less than the garage door opener and be more accurate.

7

If you do a search on this forum for "lap timer" you will find a lot of information on using IR transmitters. A lot of them include code and schematics which might help you get headed in the right direction.

8

Thanks all for the answers. This helps me a lot. I think I will scrap the garage door sensors and look into the infrared beam sensors. Looks like their reaction time should be sufficient. There is usually races after races so I'll set it up to reset itself after 20 seconds or so. Thanks again!

9

Lodgingsensor:
Thanks all for the answers. This helps me a lot. I think I will scrap the garage door sensors and look into the infrared beam sensors. Looks like their reaction time should be sufficient. There is usually races after races so I'll set it up to reset itself after 20 seconds or so. Thanks again!

Might want a button or two and some leds. Connect a red button or switch to the board reset.

Check these rocker switches from a salvage warehouse, some are well built. Prices so-so to good.
Years ago they had switches with the flip-up covers, I forget if I got any.
http://www.allelectronics.com/category/720/switches-rocker/1.html
http://www.allelectronics.com/category/716/switches-pushbutton/1.html
http://www.allelectronics.com/category/730/switches-toggle/1.html
http://www.allelectronics.com/category/708/switches-key/1.html

With hardware like that available, don't you neeeeed buttons?

The system should track races by states like 0=ready --> 1=start --> 2=finish --> 3=display --> 0.

And here's a thought. Can you lay a 2x4 across each lane finish line? It would have to be held down enough to stay in place, might be asking a lot I dunno. But a piezo disk vibration/"door knock" sensor at one end would pick up a lot less than the board getting run over at speed by a snowmobile. You could know which one hit first as close as you place the boards right. These disks are used as sound pickups, they're sensitive.