Im doing a project and need some help....

boebot_fanatic

Hi im in 2nd year electronics and am starting a project using the boebot to map out an unknown enviroment.
Any ideas about getting started would be greatly apprieciated (i.e. how do you get the thing to map out the dimensions of the room?)

achilles03

I can think of two ways, one easy (but not accurate), one harder (but accurate)

One way (easy way) is to have it go until it bumps into a wall, turn 90 degrees and go again until it hits another wall..... that should be the corner, and you can use that as a starting point. Then start timing how long it's traveling. Turn 90 degrees and go until it hits another wall, all the while measuring the time it's traveling (or wheel revolutions?) before hitting. That will give you one dimension (if you know the velocity or wheel size, depending on if you're using time or wheel revs)... repeat the turn/run cycle again for the other dimension. Maybe have it check to make sure it's following the wall (and not wandering off) for increased accuracy.

Another way (the harder way) would need additional equipment. It involves the bot finding a wall and following the perimeter of the room somehow, and have 2 "locating" beacons (separate from the bot, a know distance apart but anywhere in the room). If it knows it's location relative to the beacons, it can determine more accurately the dimensions of the room. The concept of behind aircraft VOR comes to mind...

For the beacons, maybe have a slowly spinning stepper motor with an IR LED flashing on top. As the motor rotates, have the frequency it's flashing vary. At 0 degrees, it might flash at 100 Hz... and have it flash faster as it rotates, then reset again at 0 deg. The second beacon you might offset to start at 400 Hz (so the bot knows which one it's sampling), and increase the frequency by the same amount as it changes degrees. The bot can stop until the beacon's beam "crosses" it, sample the flashes, and determine where it is in relation to the beacons. Just make sure the beacons don't overlap (shut one off when they cross paths) so that the bot doesn't try to sample both at the same time. It'd involve some math embedded in the programming, but that'd be accurate, doable, and cool.

Dave

achilles03

Oh, oh, even easier... just have the bot find the corners of the room and sample the beacons at each corner. Have only one beacon operate at a time, and have the bot wait until it's sampled both before moving to another corner.

Dave

boebot_fanatic

Thanks Dave

I was also wondering about infra red detection to avoid obsticles around the room and how can this be stored in memory??

achilles03

You're getting into some more complex programming there. I imagine the first thing you want to do is determine how the bot will remember the room... maybe think of it as a plane defined by blocks of X and Y coordinates. When it moves fully into a block without being hit, mark that coordinate as "open". Where there's an obstacle, record that block as "closed". You'd need a good position sensing system to make that work (like the beacons or something else). Once you've mapped out an obstacle, you could have a simple subroutine that determines if the block it's about to move into is open or closed... if closed, it might turn to the next block and determine if it can turn back on course...

Hope that helps,
Dave

boebot_fanatic

thanks!

upand_at_them

boebot_fanatic said...
Hi im in 2nd year electronics and am starting a project using the boebot to map out an unknown enviroment.
Any ideas about getting started would be greatly apprieciated (i.e. how do you get the thing to map out the dimensions of the room?)

boebot_fanatic said...
I was also wondering about infra red detection to avoid obsticles around the room and how can this be stored in memory??

Doesn't anyone in school TRY to think anymore?

·

George Sutton

No kidding.· When I was in both electronics tech school AND university EE, my Profs would have had a COW if I didn't take time to explore on my own, and THEN ask for particular help.

upand_at_them said...

boebot_fanatic said...
Hi im in 2nd year electronics and am starting a project using the boebot to map out an unknown enviroment.
Any ideas about getting started would be greatly apprieciated (i.e. how do you get the thing to map out the dimensions of the room?)

boebot_fanatic said...
I was also wondering about infra red detection to avoid obsticles around the room and how can this be stored in memory??

Doesn't anyone in school TRY to think anymore?

boebot_fanatic

screw you, all of you. im a lazy bastard and at the end of the day i wont even do the project, ye BASTARDS!!!! I'LL FIGHT YE ALL TO THE END

Bean

LOL boebot_fanatic, I think what we/they are looking for is for you to provide example of what you have though of so far. Then people will be more willing to help, if you show that you have at least thought about the problem and have tried a couple things.

Don't get discouraged, but what you are trying to do is not easy.

Bean.

Post Edited (Bean) : 1/26/2005 1:47:41 PM GMT

Nate

Now THIS is a real discussion.· Let's all remember that it takes all types to keep this world interesting: The inventive geniuses, The lazy bastards who steal the geniuses ideas, and lets not forget the really stupid people who by some stroke·of luck manage to get the girl, the money and the fame.· [noparse]:)[/noparse].

nate

George Sutton

Boebot_fanatic,

I apologize for my previous post. I should have been more supportive or constructive rather than destructive. Please continue to post your questions, as lots of good professionals including achilles03 and Bean, among many others, can offer great assistance. Please forgive my inappropriate post, and don't give up on your project.

boebot_fanatic

Sorry guys for losing the head!