invisible (or hardly) tracking marker for a robot
I was trying to think of something I could use to have my robot track a path, like a line following robot, where the line on the ground would not be easy to see with the human eye. The ideal thing would be a transparent piece of tape that an IR or color sensor picks up the way IR sensors can detect a white line on a black background. Other more exotic alternatives could be very small RFID stickers, or some kind or marker that is really small or hidden from view.
The idea is to be able to have my robot follow a path on a hardwood floor without having to paint a big white line on the floor.
This seems like a problem that others have probably thought about, but I didn't get any good hits from Google. Does anyone here have suggestions? Ideas? Something they saw someone else try?
Thank you for your help.
The idea is to be able to have my robot follow a path on a hardwood floor without having to paint a big white line on the floor.
This seems like a problem that others have probably thought about, but I didn't get any good hits from Google. Does anyone here have suggestions? Ideas? Something they saw someone else try?
Thank you for your help.
Comments
I think the jest of it is each beacon would flash its IRED at different frequencies. The robot would know ahead of time were each beacon is located. The robot could then triangulate its own position base on the angle to each beacon.
Duane
I just use black masking tape on my kitchen floor and leave it there, even though it comes up easily. But, hey, I'm single and can get by with stuff like that!
-Phil
I'm pretty sure the paint is transparent to visible light. I doubt you want to paint your hardwood floors with it.
Duane
So they think! Anyone who's gotten a ticket from one of these (not me, but my son) knows they're color cameras. No amount of IR blocking paint is going to keep you from getting a ticket. Those products are a sham, at least for any red light camera made in the last decade.
I second Phil's suggestion of an "invisible ink" which will fluoresce under a UV LED. The only trick is to get the fluorescence into the green/yellow region where you have a better chance of detecting it using an ordinary photo detector. A CdS cell works well here, but is slower-acting than a phototransistor. So-called blue enhanced photo detectors tend to be fairly expensive. (Parallax has one, though, if you go this direction.) You can also try a phototransistor in a CLEAR casing. Don't get the kind with the built-in IR filtration.
-- Gordon
Thank you everyone for your good suggestions!
I've found glow-in-the-dark stuff fluoresces very nicely with a violet laser. Some glow-in-the-dark paint can be nearly invisible in daylight.
@Gordon, I thought they use IR photography to cut through the glare of the windshield? Those type of things are much too high tech for my neck of the woods.
P.S. I grew up in Pacific Beach, San Diego. What the heck I'm I doing in Idaho?!
It's the opposite. IR increases light glare. UV filtration + polarization reduces glare. And that's exactly what any modern red light camera does.
The typical setup may include an IR camera in case the photoflash doesn't trigger, but most now include a VERY high resolution color camera capable of maintaining resolution even at 50X or 100X zoom, plus a color video camera.
(IR plus photoflash is a mess; the photoflash is used for the color image which has IR filtration, just like our eyes see it. They use both to circumvent exactly this sort of thing -- and likely send an additional violation if they see any attempt to block the license plate!)
A few months back I met a woman at a craft show at the Del Mar Fairgrounds that was headed to Coeur d'Alene. Greener pastures, I guess. Personally I'd have a hard time living outside Southern California.
-- Gordon
This reminds me of an Idea I had a while back, one I'll never build and test.
Put an LCD screen over the plate with a activated bar wide enough to black out a couple of the numbers. Then scan the bar across the plate fast enough that a human can't see the bar. It would look like a slightly tinted plate, but otherwise normal. A camera with it's shutter fast enough to capture a moving car, would see some of the plate numbers blocked out.
When I thought of this I didn't know video cameras were involved. At lease a human would have to watch the video and figure it out from several frames, A computer couldn't just send you an automated ticket.
I was planning it as a political statement, but the installation of cameras in my community was killed by others quicker and louder than I.
That's so pre-Y2K. It always seemed to take more effort to maintain the lines than the robot ever saved.
@erco, I'm impressed that your company was shampooing carpets once a week 12 years ago. I think my company might have shampooed the carpets 12 years ago - cost cutting and all.
'Interesting idea! Bright yellow polypropylene rope or sash cord might also work.
-Phil
all just a thought with little resourcing
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