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Projecting a 'target' dot from the barrel of a toy Sherman tank Answered

I would like to modify a 1:35 scale model tank (it's about 6-7 inches long) so that the barrel projects a dot on the wall and I can determine whether or not 'firing' the tank hits a target.

A low-power laser would obviously project the dot, but there are two big problems: the risk of it getting pointed at someone's eye, and the logistics of mounting it in the chassis. Regarding the safety issue, that danger could be lowered by limiting the laser to a 0.1 second burst each time. That's still not safe enough for my tastes, so I don't know whether I'm willing to go that route. And as for the logistics, the turret of the tank will be full of servos, gears, etc., so the laser unit would have to be in the hull of the tank, with the beam channeled to the barrel somehow. Would a length of fiber optics do the trick? Does anyone have other suggestions for channeling the laser?

It would be easier from an engineering standpoint to mount an ultra-bright LED in the barrel, but is there any way to focus that into a dot?

And finally the target would have to be big enough that there's some chance of actually hitting it - I'm thinking the size of a quarter. I haven't found any laser/visible light receptors that big - any ideas?

As an aside, I don't like posting questions without having done some legwork first - I have actually researched this, but haven't found useful info...



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2 years ago

A 1/2 milliwatt laser such as you can purchase at the dollar store has no danger at all !!