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Thomas Corcoran

datalogging - 4 views

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    how to data log
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    check this bad lary out
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.
  • ...4 more annotations...
  • 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
  • ...1 more comment...
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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
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
Anthony DiVirgilio

Read Ultrasound (cm) - LabVIEW 2009 LEGO MINDSTORMS NXT Module Help - National Instruments - 3 views

    • Anthony DiVirgilio
       
      here is a good code example for the ultrasonic sensor
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    shows how to use basic ultrasonics in labview
Bryan Kelleher

Add an Ultrasonic (Sonar) sensor to ClareBot Lego NXT MindStorms Robot DrGraeme.net fre... - 7 views

    • Thaddeus McKeon
       
      also shows how to program in a different version though
  • Adding a vertical ultrasonic sensor to ClareBot allows the robot to go around an arena without touching the walls
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    shows how to build a simple wall following robot
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    Although this is an older version, the placement of the Ultra sonic sensor is a good thought
Anthony DiVirgilio

NXT Data Collection - NI Discussion Forums - 3 views

  • sounds like for your application you might want to use the Log Angle (red/blue/green) nodes to acquire your data. This lets you sample at a specific rate for a given amount of time and saves the data to a file called RedData.dat, BlueData.dat or GreenData.dat depending on the color of the Log Angle you chose
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    how to log data
Bryan Kelleher

Google Translate - 6 views

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    I think this will be very helpful
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."
Andrew Drogan

My Library - 2 views

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    if a light source is detected on the left of the robot, the left motor will speed and the robot will veer away from the light source.increahttp://gicl.cs.drexel.edu/wiki-data/images/7/72/LearningRoomba-SensorsActuators-StudentsGuide.pdfse
Jarid Brogan

maze nxt - Bing Videos - 2 views

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    demonstration on maze bot
Thaddeus McKeon

Free Lego NXT Mindstorms Robotics tutorial Climb A Mountain Use of gears Challenge 30 - 6 views

    • Thaddeus McKeon
       
      very helpful and useful
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    The bottom of this page explains how to create differnent gear ratios and how they work
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    they are using a diffrent program
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    we could make the program in labview, they were just using a piece of wood on books.
Thomas Helm

Slope climber - 6 views

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    It a good idea we will just have to narrow the body to within 9ins
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
Anthony DiVirgilio

Gear and Wheels Part 1 - YouTube - 6 views

    • Anthony DiVirgilio
       
      really good demonstration of gear ratios at work
Thomas Corcoran

NXT Basic-1: NXT Basic - Ultrasonic Sensor - 1 views

  • The Ultrasonic Sensor uses the same scientific principle as bats: it measures distance by calculating the time it takes for a sound wave to hit an object and return – just like an echo
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    basic review on the ultra sonic sensor
Thomas Helm

Roomba Discovery Review and Testing - Digital Bits Technology Column - 1 views

    • Thomas Helm
       
      This is a way of testing to see if it cleans completely
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    This talks about how it was different wen someone tested it by putting a chair in the way of the area it was cleaning
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    great idea
Bryan Kelleher

SPOILER ALERT! - 9 views

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    this is helpful for creating less complicated block diagrams
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    This is really good to know for when everything starts to get really crazy
Thomas Helm

Avoiding Falling off - 5 views

i agree a lot with declan, by how everyone is looking most people are going to be using ramps so im gonna try and find something better

light sensor

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