Society of Robots - Robot Forum
General Misc => Misc => Topic started by: Gordo4444 on February 11, 2008, 07:34:43 PM
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So for my graduation project for highschool I was going to build a robot that would complete a custom maze that the teachers would make. So I've been working on some ideas... It would either have a camera or an IR sensor on it that will read the wall/floor position and tell it where to move from there. It would be differential drive bot (2 big wheels and a small undriven wheel for stablility). This is the pseudo-code I've been thinking of. I haven't worked out how it will see so keep that in mind.
Pseudo-code:
Start moving forward
If it sees a wall infront of it, turn left
If there is a wall to its left, turn right instead
If it is at a dead end, do a 180 turn
When it reaches the end (A bright orange spot or something) Stop
So thats what my idea so far is. But i have a few questions...
1. Micro-processor- Would the microprocessor from the 50$ dollar robot work? or would I have to get a new one? If I DO have to get a new one, Would it be better to buy one or to make one? If it would be better to make one, anyone have schematics?
2. Vision- I was thinking I'll either need an IR scanner or a camera which the microprocessor will interpret. But which would be best? The IR scanner or camera? Or another vision sensor that I didn't think of? Maybe touch sensors?
Thats what I have so far, but I will update this as I have questions... Thanks!
~Gordo~
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nice desighn
couple things
use a led and photocell setup to fing the dot
use two scanning ir sensors so that it is more accurateand takes less time to navagate.
you can use the $50 robot circut baord but use the ATmega 168 chip so thats it's faster
http://www.societyofrobots.com/step_by_step_atmega168_swapout.shtml
maybe use DC motors instead of servos for speed
how will it know if there is a opening to go through and how will it know if its already tgone past a spot (ot could go around in circles)
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http://www.societyofrobots.com/programming_wavefront.shtml
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If you are getting your teachers to bulid the maze, makes sure its a maze with an entrance and an exit, instead of like the micromouse one, where the ojective is the centre. Because your algorithm can't solve many of the micromouse type mazes.
There are analogue versions of these simple mice, called wall followers. You might get a load of helpful info searching for these.
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I planned on using DC motors instead of servos. Mainly because I don't have any servos... I was thinking of a different idea for the pathfinding... It will have 3 IR sensors, 1 in front and 2 in the sides. Every time it sees a possible left turn, it turns left. If there is no left turn, it go's straight. If it can't go forward, and it can't turn left, it turns right. If there is no right turn possible, it does a 180 and resets the algorithm. Thus, the next time it comes to a left turn, it turns left and so on and so forth. And eventually it WILL find the exit. I'm almost positive. Please someone correct me if I'm wrong, and post an example. This will eliminate the need for complex pathfinding algorithms. The only problem, is that there is a chance that it will take forever to solve the maze. To combat this, i will make the maze small enough so it will take a maximum of 5 minutes or so to solve it. I also like the entrance exit idea, better then the "micromouse" one. This was my idea of the maze. Build a flat piece of wood with slots cut into it on a grid pattern. Then build several small walls that will slid into the slots in the flat piece. That way, they can make what ever maze they want, and it will show that it can solve ANY maze. So what do you guys think? Am I in over my head?
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Gordo4444, the maze solver algorithm you describe is called 'wall following' . . . its the simplest maze solver you can do, and a good start for a beginner. As long as the solution is connected to a wall, the maze can be solved. Otherwise, the next simplest (that can always find the solution) is the wave front algorithm.
As for motors and servos . . .
http://www.societyofrobots.com/robot_faq.shtml#servo_motor
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Sweet, thanks for all your help guys. This really is a great site. One question though. Im no a tight budget and I really don't like ordering things online. I'd rather buy them from a store. Would Radioshack sell servos? Or would I have to go to a hobby shop?
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Would Radioshack sell servos? Or would I have to go to a hobby shop?
Im not sure if they still sell them, but Radio Shack at one time sold Vex servos for a reasonable price.
Hobby shops should have servos too.
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If you rethink ordering online, ebay has A TON of cheap servos! ;D
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I guess ill break down and check eBay. Thanks for the tip!