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Building a laser car finder, expert input welcome!

Sethalvo

Sethalvo

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I've been working with vehicle electronics for most of my life, and have a lot of experience with car alarms... I had an idea the other day and immediately started ordering parts---here's the concept:

1. Your car is out in a huge parking lot at night, and you can't remember where you parked

2. You press the auxiliary channel on your car alarm, and green beam shoots up from where your car is

3. a police helicopter lands next to your car, and you get arrested

Hopefully step 3 will not be necessary. I ordered this laser module from Laserlands

Other supplies are:
  • Coby 12vdc to 3vdc adapter
  • DEI 528T pulse timer (to keep laser on for 10 seconds only)
  • 8616 mini relay to step up 50ma aux output of car alarm

Will I need a heat-sink with this module? Has this idea already been thought of? Any problems with the laser being exposed face-up during the summer time? Input and criticism is welcome.
 





photonaholic

photonaholic

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Sounds cool, face up = bird poop, rain, dust, etc.....

Why not a xenon strobe light, gets attention, sturdy, durable, etc...
 
Sethalvo

Sethalvo

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lol, it's going to be on the inside of the car at the base of the dash. I tried it with one of my lasers and the windshield doesn't impede the beam much at all. Why not strobes? Because a huge green beam is way cooler! :yh:
 
photonaholic

photonaholic

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on the dash, ok that would be far better, sure would freak out anyone standing close to your car at the time.
 
Sethalvo

Sethalvo

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Yeah that's what I'm hoping for. Let's face it, it's not entirely practical. I'll get a kick out of it though, and I'll post pictures of the installation and end result.
 
Rafa

Rafa

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You sholud defocus it. As the banner say, you shouldn't point a laser at an airplane.
 
photonaholic

photonaholic

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Pointing it up through a windshield would reflect a lot of it back into the car, not enough light from a low power module would really pass through the windshield to make it up to a plane.
 
bobhaha

bobhaha

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photonaholic said:
Pointing it up through a windshield would reflect a lot of it back into the car, not enough light from a low power module would really pass through the windshield to make it up to a plane.
Click to expand...

Glass has ~4% reflectivity on each side of the glass... so 92%of the power is going straight up... that means at 100mw, it would allow +-92mw. Also for 10 seconds I really doubt it would be much of a problem. I personally don't think its a good idea, but sounds fun and cool. Oh and btw if you point it straight up the helicopter/plane, it must be directly over the beam to be affected... and since they are not made of glass, it will not pass into the cockpit, so pilot should be unaffected by the laser.

Hope that helped! -Adrian
 
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Asherz

Asherz

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bobhaha said:
Glass has ~4% reflectivity on each side of the glass... so 92%of the power is going straight up... that means at 100mw, it would allow +-92mw. Also for 10 seconds I really doubt it would be much of a problem. I personally don't think its a good idea, but sounds fun and cool. Oh and btw if you point it straight up the helicopter/plane, it must be directly over the beam to be affected... and since they are not made of glass, it will not pass into the cockpit, so pilot should be unaffected by the laser.

Hope that helped! -Adrian
Click to expand...

It's a cool idea, but surely if your in range to use any remote control such as car keys to unlock your car, your head lights flash and beep when you unlock anyways...

It would only be useful if the range on the laser remote is insanely far.
 
photonaholic

photonaholic

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There is probably 100 reasons for it being impractical to do......

one of them would be that on o clear night, side viewing the beam would be difficult even at 100mw.

On a foggy night, heck yeah....but I take my labbies out at night and even at close range side viewing is difficult.

Another more serious factor to consider, windshields are angled as such that the reflected part of the beam could pass out the back window and be at eye level of some innocent bystander.
 
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photonaholic

photonaholic

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BobH said:
Nice creative thinking on this idea, but not really practical. A product will never be authorized that's over 1mW, and at that power, side viewing won't happen even at night. While I applaud the search for something less annoying than that idiotic blast of the horn when somebody arms or disarms their useless car alarm, I think a strobing LED is probably a better bet. And cheaper. And about as annoying as a strobing bicycle headlight which is as annoying as it gets. But nothing is more annoying than a blast from a car's horn at full volume to indicate alarm manipulation.
Click to expand...

I hear ya, hell anymore in cities people ignore car alarms anyhow.

A flashing LED on top of the radio antennae would be perfect.
 
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steve001

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Consider how are you going to operate this device in the extreme temperatures found in car interiors ?
 
Asherz

Asherz

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steve001 said:
Consider how are you going to operate this device in the extreme temperatures found in car interiors ?
Click to expand...

Good point, cars get cold inside at night (over here anyways) and greens are particularly temperamental to low temps.
 
Sethalvo

Sethalvo

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  • Great replies guys... Here are a few considerations/concerns
  • The remote I am using has >2000ft range, so distance is not a worry
  • Led at top of the antenna = awesome idea!! Not a laser but still cool
  • As far as reflectivity, I've tried it with my lasers and it doesn't seem to be a problem
  • Side viewing - yep, seems to be a problem. The module is 50mw, and unless it's foggy I don't see it being too effective. I set up 100mw laser on a tripod last night near some light pollution and I stood back---very hard to see. (I ordered the parts already, oh crap)
  • The extreme cold...good point. I usually go out into the cold with my lasers right after they were in my house, so the components are warm. I never considered that this unit will be in the car for long periods of time. Does the heat affect this too?
  • I'll post pics of whatever I do regardless, maybe a bright green LED on the antenna, great idea photonaholic! I wanted to use a laser (and still might) but that seems way more practical
 
Rafa

Rafa

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Asherz said:
Good point, cars get cold inside at night (over here anyways) and greens are particularly temperamental to low temps.
Click to expand...

Yeah, about 7-8ºC here in Spain and I had to warm it up with my hands a lot. And in summer the car can get up to 50ºC inside of it.
 
Sethalvo

Sethalvo

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Confirmed: Doesn't work

I set up my Opto in my car facing upwards (on a small tripod on the dash). I stepped outside the car and looked---it was bright as hell and shining straight upwards. As I stepped backwards, the beam became less and less visible, but not because I was viewing it from the side. The beam diameter is so small, that how COULD I actually see it from more than 20 to 25 feet away? Sure, I can make out the beam, but that's because I know exactly where my car is. It doesn't stand out enough to help me find the car. Actually, honking the car horn would be a beam finder. Now I need to think of something cool to do with this 50mw module that's being shipped to me. Thanks for all your help guys!
 
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