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Thomas Helm

Something to use - 6 views

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    This is im pretty sure everything we have
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    i think that this is a great idea
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    this would probably work very well and if we added a touch sensor *i dont know if they had one* which would activate the ultrasonic sensor and it would search and pick a path
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    That was a good idea declan thanks buddy
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    OK 0_0
Thomas Helm

Light sensor and Ultrasonic thats it - 4 views

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    this could work but what if the robot turned and started going the wrong direction back towards the start???? it only follows the walls which could lead the robot back to the start not the finish
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    anyrobot we do is basically going to be folllowing the wall though and it would have to go all the way to the end to start going back to the beginning
Jarid Brogan

NXT Tutorial - 2 views

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    This tutorial is divided into two sections selected on the left. The "Essentials" are things every NXT programmer should know. Some of these movies have exercises directly under them. It's important to do these exercises, not just assume you "get it."
Bryan Kelleher

LEGO.com MINDSTORMS : Community : NXTLOG - 4 views

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    the way the ultra sonic sensor is set up is a good idea
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    I feel the way they set up the light sensor is a little to far out
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    we are gonna have to place the ultrasound or light sensor under three inches if we are following the inside walls, but thats an individule decsion. we could use a code similar to the wall following code in the romba project.
Thomas Helm

LabVIEW Add-ons for LEGO® MINDSTORMS® NXT - Developer Zone - National Instrum... - 5 views

    • Alexander Laferriere
       
      this shows how to turn on a motor if the button is pressed so if it is not pressed it will stop
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    LabVIEW Toolkit for LEGO MINDSTORMS NXT Program and control NXT devices with the full power of LabVIEW Get real-time updates from the NXT device during program operation with LabVIEW front panels Create native blocks for LEGO MINDSTORMS NXT software Figure 1.
Anthony DiVirgilio

How to Solve a Maze - 3 views

  • Wall follower Method:
    • Anthony DiVirgilio
       
      this would probably be consistant
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    good techniques for mazes
Andrew Drogan

Single Sensor « The Roboticist - 4 views

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    In this setup, a single light sensor is positioned on the robot and programmed to follow the outer-edge of a black line. We commonly refer to the robot executing a 'Z' pattern while following the black line.
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    a z pattern might not b the best idea on this because we have a certain time we have to do
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    if we keep it between a very specific max and minimum then it will not zig zag as much and will appear to go straight
Joshua Wilkinson

Line Detection - 9 views

it would work on the other tracks if the robot dosent drive off the line a lot.

Joshua Wilkinson

NXT Line Follower - 2 views

  • When line following, the robot will try to align itself centered over the boundary between white and black (not centered over the black line), with black to the robot's left.  Here the brightness seen by the sensor is halfway between the black/min and white/max readings
    • Joshua Wilkinson
       
      This would be useful since we get the value when its over the tape and table, we can also find the value of the sensor when its directly over the tape then the table seperately.
  • When prompted to sample the "Min" or "Black" reading, position the sensor so that the red spot is centered over the line and then press the Enter button on the NXT. When prompted to sample the "Max" or "White" reading, position the sensor so that the red spot is completely over the surface away from the line and press the Enter button on the NXT.
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    Before line following using either the LineFollow2 or LineFollow5 program, you should "calibrate" the light sensor to the actual conditions expected. With the sensor mounted on the robot where it will be used, and the robot placed over the actual line it will be following, a calibration process takes two light sensor readings, one directly over the line (minimum = darkest), and one over the surface away from the line (maximum = brightest).
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    if we follow the edge of the line we will always be between the max and the minimum values. therefore, it can detect both values and stay between the min and the max.
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    we have to figure out how to correctly calibrate the sensors
Declan Coen

PID Controller For Lego Mindstorms Robots - 7 views

  • light sensor "sees white" then we know it is left of the line's edge (and the line). If it "sees black" then we know it is to the right of the line's edge (and on the line). This is called a "left hand line follower" since it is following the line's left edge
  • We need to know what values the light sensor returns when it "sees white" and when it "sees black". A typical uncalibrated sensor might give a "white" reading of 50 and a "black" reading of 40 (uncalibrated, on a 0 to 100 scale). It is convenient to draw the values on a simple number line to help visualize how we convert light sensor values into changes in the robot's movement.
  • Below are our made up light values for white and black.
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  • We'll just divide the range into two equal pieces and say that if the light level is less than 45 we want the robot to turn left. If it is greater than 45 we want to turn right. I won't go into how exactly the turns should be done. I'll just say that gentle turns work well for a fairly straight line
  • line with lots of curves usually needs to be making sharper turns. For gentle turns you might use Power levels of 50% on the fast wheel and 20% on the slow wheel. For sharper turns on a curvy line you might need to use 30% power for the fast wheel and coast or brake the slow wheel. Whatever power levels you use the numbers will be the same for the two turns, you just switch which motor gets the big number and which get the smaller number (or a stop command).
  • This type of a line follower will follow a line but it isn't very pretty. It looks OK on a straight line with with the motors programmed for gentle turns. But if the line has any curves then you have tell the robot to use sharper turns to follow line. That makes the robot swing back and forth across the line. The robot only "knows" how to do two things; turn left and turn right. This approach can be made to work but it is not very fast or accurate and looks terrible.
  • In the above approach the robot never drives straight, even if it is perfectly aligned with line's edge and the line is straight. That doesn't seem very efficient does it? Lets try to fix that. Instead of dividing our light value number line into two regions lets divide it into three.
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    seems useful for following a line effectively
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    this is a really good technique
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    the top of this article explains how it would be easier to follow the edge of the line rather than the center of the line. As it detects the white it will turn back to the black and as it detects the black it will turn back to the white.
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    i found the edge thing on another site too
Andrew Drogan

Lesson on how to follow the line - 3 views

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    this gives you a good strategy to find the line after you fall off
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    This lesson will help you to follow the line better and more efficiently
Declan Coen

electricbricks » Line Follower in LabVIEW. State Machines - electricbricks - ... - 6 views

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    this is a possible way we can program the line folllower excluding the ultrasonic sensor
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    you can use the ultra sonic sensor for the maze bot later
Thomas Helm

Nxt - 7 views

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    this shows how to get an NXT to keep on the line where it should turn and all taht good stuff
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    shows different light sensor values you should get around when you are going off the tape
Bryan Kelleher

How to make a line follower with only one sensor - Andy的網路日誌 - 無名小站 - 3 views

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    This is a good way to find the line if you may have fallen off of it.
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    this is a good way to make sure you dont lose the line
Alexander Laferriere

Vision Subsystem v4 for NXT (NXTCam-v4) - www.mindsensors.com - 1 views

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    what does this do?
Anthony DiVirgilio

http://drgraeme.net/DrGraeme-free-NXT-G-tutorials/Ch102/Ch102V1G/default.htm - 0 views

  • light sensor moved towards, and then away, from the line edge, (and then again towards, and then away, and so on…) as shown in the two photos below.
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    I know we don't have 2 light sensors but it is nice to know one way of doing it
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