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Inferred drag strip timing system? — Parallax Forums

Inferred drag strip timing system?

HammerHammer Posts: 4
edited 2006-09-13 14:52 in BASIC Stamp
Hello folks,

I am not a basic stamp user yet, but I want to build a little project which I might use this for.

I want to build a timing device for a drag strip! The trackk is 500ft long and I thought I might be able to use two sets of garage door opener sensors for inputs to start and stop the timer. I am wondering if anyone has used garage door opener sensors as inputs on the Basic Stamp? Or is there another low cost inferred sensor of choice? Also what kind of digital display would I need to record seconds down to hundreths of a second?

Any suggestions would be great!

Thanks
Hammer

Comments

  • JonathanJonathan Posts: 1,023
    edited 2006-09-12 15:40
    Hammer,

    Should be no problem to do. I made a similar setup to measure the velocity of a Gauss cannon. Here is a link to it: http://madlabs.info/stamp_velocity_timer.shtml

    I have actually since built a better one but have not yet made a page for it. I am sure you can use garage door sensors as you suggest. I used IR leds and phototransistors. If you really want hundreths of a second, you will want to get the fastest Stamp you can, or consider the SX series of chips. As to a display, I would reccomend a serial LCD, which will make it simple to display any data you want.

    HTH,

    Jonathan

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • HammerHammer Posts: 4
    edited 2006-09-12 16:47
    Do I replace the switches with the garage door sensors in you circuit, or do I replace the emmitter circuitry? Where do I get a display like that?

    Like I said I'm new at this stuff.
    Thanks
    Hammer
  • JonathanJonathan Posts: 1,023
    edited 2006-09-12 17:06
    Hammer,

    I have never used garage door opener sensors. Hopefully someone will chime in here. Do you have the sensors already? If so and you can give us any information, that would help. Search around on the web, I'm sure someone has used these with a Stamp before.

    As far as the display, look on the Parallax website. They sell them there, with complete instructions and code samples.

    On my example, ignore the switches. You want to use the photodiodes. The switches are for the user to change settings. You can go to radio crack and get all the parts you need to implement the circuit I used. One thing you should know is the range of such a system is limited. How wide is your track? Also, bright light or flourescent lights can interfere with such a simple system. There are other ways to skin the cat if need be.

    HTH,

    Jonathan



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • HammerHammer Posts: 4
    edited 2006-09-12 18:02
    Jonathan,

    I have absolutly no idea of the sensors I currently have. There are no markings on them whatsoever. The only thing I found was on the circuit boards which is printed "31200A-R2
    PC-A-P92-94V-0, and 31190A-R2 PC-A-P92-94V-0 (whatever all that means, I don't know) I will try punching those numbers into the web and see what comes up though.

    I see the displays at the site.

    The track is going to be 10 feet wide x 500 feet long and be used outside in varying degrees of light.

    Thanks again.
    Hammer
  • JonathanJonathan Posts: 1,023
    edited 2006-09-12 18:49
    Hammer,

    I have doubts that the sensors you have or the ones shown at my site will work for you, at least reliably. The IR led setup I use will not work for sure.

    I think you need to find another sensor type to use. One might be a pressure switch connected to a length of hose across the track. When the vehicle crosses it, it pressurizes the hose, activating the switch.

    What kind of vehicles are we talking here? How heavy?

    Jonathan

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • ChrisPChrisP Posts: 136
    edited 2006-09-13 02:42
    The circuit should work actually, replace the IR emitter with a laser pointer, you can easily get 20ft of range, and it will make alignment far easier. Be very careful using them though because looking into one can damage your eyes. For outside use put the detector in the end of a piece of tube painted flat black inside to shield the detector from stray ir.
  • HammerHammer Posts: 4
    edited 2006-09-13 11:21
    Were drag racing snowmobiles on grass, so they would puncture anything we place on the ground with the studs in their tracks.

    I like that laser idea! Is that just an ordinary laser pointer, or is it something which needs to be wired into the system?

    Thank you
    Hammer
  • JonathanJonathan Posts: 1,023
    edited 2006-09-13 14:52
    Chris, Hammer,

    The laser pointer sounds like a great idea. It doesn't need to be wired into the circuit in any way. One thing is I would try to get a half way decent one, not the cheapest you can find. I built a laser communicator for my students to play with and discovered that some cheap ones do not like being left on for extended periods of time. One of them burned out and another will work again after a cool down period. I finally wound up buying a nice green laser for the project, but mostly because its cool. I would try a decent quaity red one for this project.

    Let us· know how you progress!

    Jonathan

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
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