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### Author Topic: Detecting Density of lines ?? -Help  (Read 2935 times)

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#### evilknight007

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##### Detecting Density of lines ?? -Help
« on: September 08, 2007, 10:00:20 PM »
Hey Guys .
am doing an autonomous bot a for a competition . which should evade the obstacles and go through a exit ..
There are white lines on a surface to aid the bot guide through to the exit . The density of the lines increases as v go towards the exit .
I'm putting a copy of the statement and the pic .

Quote
The obstacles will be so placed that, there shall be only a limited number of pathways through which you may exit the arena.

There will be white lines (on the red surface) to guide the robots towards the exit. Any normal drawn to these lines will be along the direction of the exit. There will also be an increase in the density of the lines as one gets closer to the exit. The robot may use these lines to find its way out. The lines will be present only in the outer region.

Can anyone suggest a good method to do this . Thank you guys !
The Full problem statement can be found here.
http://www.shaastra.org/n/events/The+Mission+To+Mars
« Last Edit: September 08, 2007, 10:03:05 PM by evilknight007 »

#### dunk

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##### Re: Detecting Density of lines ?? -Help
« Reply #1 on: September 09, 2007, 03:23:41 AM »
so what are your ideas so far?

to find the exits i would treat this as the opposite to a line following challenge.
rather than following the white lines you want to be going at right angles to them.

line following bots often use reflected light from bright LEDs sensed by LDRs.
i would use 2 lines of LDRs along the length of the bot, one line on each side so it can tell which side is reaching a line first and adjust it's heading accordingly.

dunk.

#### evilknight007

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##### Re: Detecting Density of lines ?? -Help
« Reply #2 on: September 09, 2007, 06:33:34 AM »
|----------- |
|  *      * |
|  *      * |
|  *      * |
|  *      * |
|-------------|
u mean someting like this ?? where the * is for LDRs??

#### evilknight007

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##### Re: Detecting Density of lines ?? -Help
« Reply #3 on: September 09, 2007, 06:43:09 AM »
Quote
so what are your ideas so far?

I thought of using two IR detectors at the sides and when both the sensors detects the line at the same time then to move the bot forwards .. It has its short comings .and what exactly is a LDR.

+-----------+
+           +
===+           +===
+           +
+           +
+-----------+

Planned to something like this . Using IR Detector emitter pair.

#### Admin

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##### Re: Detecting Density of lines ?? -Help
« Reply #4 on: September 09, 2007, 02:23:34 PM »
To calculate the density, measure the time (use a timer on your microcontroller) it takes for your robot to pass between two lines.

At a constant robot velocity, the shorter the time, the more dense the line spacing.

#### evilknight007

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##### Re: Detecting Density of lines ?? -Help
« Reply #5 on: September 09, 2007, 08:36:16 PM »
Thanks admin .
And why has the topic been shifted to Misc.?

#### Admin

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##### Re: Detecting Density of lines ?? -Help
« Reply #6 on: September 09, 2007, 08:56:23 PM »
Quote
why has the topic been shifted to Misc.?
It didnt really fit anywhere too specific . . . it could go into electronics as a sensor thing, or software as an algorithm thing . . . but misc just seemed better . . . its a subjective thing on my part

#### evilknight007

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##### Re: Detecting Density of lines ?? -Help
« Reply #7 on: September 10, 2007, 07:43:49 AM »
i don't think its getting any attention here .
i badly want some ideas .. i have already constructed the base . So should do something tat's feasible .

#### Admin

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##### Re: Detecting Density of lines ?? -Help
« Reply #8 on: September 10, 2007, 09:13:34 AM »
hmmmm whats wrong with the previous ideas?

maybe this might help:
http://www.societyofrobots.com/robot_mobot_2007.shtml
it will let you scan for the lines . . .

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