Using RSSI to locate an object

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Go with the backup plan, usehhte webcam. Processing power is cheap these days.

Reply to
The Real Andy
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achieve?

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You are wasting your time, visual object recognition is the best method in this particular instance. All the other methods (RSSI, acoustic, and IR) require a transmitter on the boat and multiple receivers. Visual recognition on the other hand doesn't require any transmitter, will work with almost any size or type of object, is simple, fairly accurate, will most likely only require one receiver, and reduces the problem to essentially a software solution.

The decision is blindingly obvious.

Dave.

Reply to
David L. Jones

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Thanks for everyones help, especially David Jones, I will be going with the visual recognition. It was originally my first choice though, as you do, I wanted to exhaust all possible options before finalising the decision as you never know there might of been an easier, more efficient way.

Josh

Reply to
Josh916

I've worked on someone else's image processing software that used a camcorder to track a lizard's frame to frame movement down a small track ~1.2M long or so.

You'll need to correct for parallax unless the camera is very high above the tank, so having a X,Y marks around the edges of the tank would help.

Python and Python Imaging Library was used to convert the colour image to greyscale first and then to two bit black and white if a pixel was either side of a set threshold value. This gave a black background with a white moving object on it that could be scanned vertically in my case to give the amount of movement in pixels which was then corrected for parallax and converted to millimetres.

Reply to
Mark Harriss

received signal strength indicator

martin

Reply to
martin griffith

I think if he can equip the box with a wire grid and have a receiver on the boat, then each wire of the grid could have a different tone signal on it. The antenna on the boat receiver would pickup the tones so the 2 strongest tones would indicate the position of the boat. He could simply program a pic micro to sample the tones and output the x,y coordinate via a radio signal from the boat. This would be an example of RSSI. This same setup may well work with the robot soccer games. Jus my 2 cents worth :) JTT

Reply to
James Thompson

Personally I think Phil is quite right to call you a stupid troll. It's not as if you are not fishing for ideas.

I'm even less amazed that one of your skills appears to be hunting down information about someone who has the gall to call you stupid.....

Strange that.

Did you use Google to find out Phil is occasionally slightly obnoxious rather than reading this 'newsgroup' for a while?

Uuuuuhmmmmmmmmm............

Anyway.

Since I am brilliant, capable of thinking outside the box and it sounds like a 'fun' way of solving your problem. What you should really do is this....

Think in polar coordinates.

Pick one of the 'vertices' of your box as your 'origin'. Get yourself three 'dual light pipe' type things and lay them out along the XYZ edges of your box as defined by that origin.

Plug the mechanical ends of your light pipes into some mechanical type rotating scheme, stepper motors with microstepping drive systems, so you can rotate them.

You will probably need some blu-tac to stop the water dribbling out.

Excellent opportunity for mechanical design of things that overcome dribble problems.

Then you shine a bit of light up one side of your dual light pipe thing and you recieve the reflected light back down the other side of it.

Lots of opportunity for transmission/modulation/detection/demodulation stuff there.

And rotate the pipes for maximum signal.

Lots of opportunity for feedback/control stuff there.

Once you have aligned all your pipes. Then all you have to do is do sums to convert the angles to where your object is.

Good stuff for the mathematics of the problem.

Now, kindly piss off and do your own research.

DNA

Reply to
Genome

Look at opencv , it has most of the functions you need , its free and os available on linux , mac and windows. Use it with c , c++ or python.

Could even do object tracking fairly easily.

Make sure you boat has a nice bright colour that stands out wll. Once you have the detection working , then you can change the colour to one with a lot less contrast to see how well your solution works.

Alex

Reply to
Alex Gibson

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