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Long range motion detection — Parallax Forums

Long range motion detection

DeathbatDeathbat Posts: 4
edited 2013-07-10 00:30 in Propeller 1
Hey guys,

I have an interesting problem and am looking for a little brain storming. I am trying to detect a large moving object from a distance of about 300 feet. The object is a semi-truck pulling into a loading dock. I have an exact point where the truck will pass, but I cant position a sensor any closer because of how the dock is layed out. It will also need to detect the truck night and day. I want to tie the input into a Propeller so I may do other things based on the input like sound an alert and log arrivals.


Any ideas?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2013-07-07 13:02
    The only thing that makes any kind of sense at that range is some kind of laser-based sensor, like the surveyor's laser mentioned in your other thread. This assumes that there's space beyond where the semi would come so there would be a significant reading difference between the case where the semi is present and where it's absent.
  • kwinnkwinn Posts: 8,697
    edited 2013-07-07 13:11
    A pir sensor with an IR lens to narrow the focus to the entry point, a low res thermal imaging chip, or a parabolic microphone to detect the diesel engine.
  • DeathbatDeathbat Posts: 4
    edited 2013-07-07 15:34
    Thanks for the input guys,

    Mike, I thought of a laser based sensor but I have not found any with that range and that I can interface with. Do you happen to know of any?

    kwinn, I dont know that a IR will get the range I need and there is no way to really put it closer (its like a big parking lot with no place to mount). I think the mic would have to many false positives since there is a highway near by. The thermal is a good idea though. I will explore a little more on that. If memory serves theres a nice thread about a low res thermal somewhere on the forums.
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-07-07 18:03
    Deathbat,

    I believe kwinn was talking about the IR heat signature given off by the engine of the truck, not quite the same as the IR from say a tv remote.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-07-07 18:19
    HobbyKing sells a laser range finder that's supposed to work out to 700m. I have one I've been meaning to hack but I haven't gotten around to doing so yet.

    If you used a more powerful laser and modified the mounting geometry, I'd think Parallax's Laser Range Finder could be made to work at greater than its standard range.

    Is there a solid background color that could be monitored? If so, the CMUcam4 would keep an eye on the area and watch for changes in size of a color blob. This probably wouldn't work well at night though.

    Could you mount a reflector beyond were the truck would be to use with some sort of electric eye (bouncing IR or laser light back to a detector)?

    I'm still itching to try the thermal sensor Phil experimented with here. Is it the low-res imager you were referring to?
  • msrobotsmsrobots Posts: 3,709
    edited 2013-07-07 18:27
    How about a garden hose and a pressure sensor?

    lay it on the ground and let the truck drive over it...

    Enjoy!

    Mike
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-07-07 18:40
    msrobots wrote: »
    How about a garden hose and a pressure sensor?

    lay it on the ground and let the truck drive over it...

    Enjoy!

    Mike

    That's the way all the gas stations did so they know when to come out to pump the gas for you. That was before the selfserve days.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2013-07-07 19:25
    Duane Degn wrote:
    That's the way all the gas stations did so they know when to come out to pump the gas for you.
    Wow! There are some really OLD people on this forum!

    (Just kidding! I remember when the attendant not only filled your tank, but checked your oil and handed out free coffee mugs -- all for what? Thirty cents a gallon?)

    -Phil
  • HarbingerHarbinger Posts: 7
    edited 2013-07-07 19:34
    Greetings,

    I would use a laser pointer, a mirror and a photo-transistor. Place the laser such that its beam will be crossed by the truck. Use the mirror to relfect the laser to a location that holds the photo-transistor. Thats it and it would cost less than 10 bucks.
  • skylightskylight Posts: 1,915
    edited 2013-07-08 12:42
    what about radar?

    http://www.conti-online.com/www/industrial_sensors_de_en/themes/ars_300_en.html
  • NWCCTVNWCCTV Posts: 3,629
    edited 2013-07-08 12:52
    What about a CCTV camera?

    (Just kidding! I remember when the attendant not only filled your tank, but checked your oil and handed out free coffee mugs -- all for what? Thirty cents a gallon?) And they would wash the windshield? All the while letting you take free maps to get you where you were going!!!
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2013-07-08 13:10
    A long, long time ago i thought I would be a smart A**** and build a simple tracking device to follow a helicopter that had a cameraman in it and down linked at our usual 7GHz. To save having a rigger point the 2 foot dish at it all afternoon I had a CCTV camera sense what quadrant the heli was in, and track it.

    All when swimmingly well ... until a rather large crow flew through the field of view and the dish followed that. All the engineers fell about laughing, the director didn't.
  • prof_brainoprof_braino Posts: 4,313
    edited 2013-07-08 13:26
    Deathbat wrote: »
    laser based sensor but I have not found any with that range and that I can interface with. Do you happen to know of any?

    DS00 from Lightware is good in broad daylight up to 350 meters, and is accurate to a couple cm.

    The newer version is supposed to cost less with shorter range, but I haven't played with those.

    http://www.lightware.co.za/index.php/2-cat-lightware
  • rabaggettrabaggett Posts: 96
    edited 2013-07-08 16:44
    Ramsey's SG7 Speed radar kit has an output so you can 'hear' the doppler shift. I bet a truck at 300 feet would make a very distinctive 'sound' that could be sampled with a simple ADC. Pretty cheap, too!. Just look for a tone above a certain pitch-speed for at least so long.. Some experimentation would be in order.
  • Mark_TMark_T Posts: 1,981
    edited 2013-07-09 06:48
    Quick question: is it always the same truck? That would make things easier.
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2013-07-09 08:52
    Seismic ? .... A strategically placed speed bump for the truck might produce a measurable reading. I remember as a kid making a crude Seismograph with a magnet suspended on the end of a spring inside of a PVC tube. At the bottom where the magnet was, a pickup coil fed directly to an Op-Amp. On trash day, the "trash truck" three houses down would set it off.
  • DeathbatDeathbat Posts: 4
    edited 2013-07-09 15:27
    Thanks for the suggestions everyone. I think my best bet is going to be radar based. I found a system http://www.southwestmicrowave.com/products/microwave-sensors/ that looks capable. I will have to do more research to make sure but I like prof_braino's suggestion of http://www.lightware.co.za/index.php/2-cat-lightware as a possible backup.

    To answer your question Mark_T, no, it is not always the same truck. They receive a variety of trucks.

    Beau, I love the simplicity of your solution but unfortunatly I cant put anything in the drive. Though now I do have to wonder what you were like as a kid.
  • Heater.Heater. Posts: 21,230
    edited 2013-07-10 00:14
    If you are looking into radar solutions check out these units: http://www.isee.biz/products/igep-radar-technologyThey have been used for vehicle detection. A thousand dollars or so gets you the radar unit combined with a capable ARM processor board running Linux.
  • FernandFernand Posts: 83
    edited 2013-07-10 00:30
    Is there a one time cost limit? Recurring cost limit?
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