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How do you do precision positioning

for a school project i'm making a robot that is connected via bluetooth to my pc and I need to have it's exact position and it has to be able to drive in a straight line.

Does anyone know what kind of sensor would be best to use and in what way it should be programmed??

Creative Commons License Idea

The idea of implementing the Creative Commons License (used on several other sites with user-generated content) was suggested to us and we're eager to get your feedback. Thank you for the suggestion AndyGadget.

If you're not sure what Creative Commons is or why it exists, take a look at the Creative Commons Website here:

http://creativecommons.org/

They also have a cute video about why they exist:

http://creativecommons.org/videos/get-creative

Terms and Conditions - V2

Dear LMR Friends and Family:

Yesterday we sent our new (first!) terms and conditions (T&Cs) for the LMR website (outside of the Marketplace, which was already governed by T&Cs) to all LMR members.

We’ve received mixed feedback. While most of you recognize the need to put T&Cs in place (when RobotShop recently purchased the site these were not in place), some feel that some of the conditions are a little heavy. Others have misinterpreted the scope of the T&Cs and RobotShop’s intent. 

Our version of the story

Hi everyone, I am Sandra Fradet, co-founder and co-owner of RobotShop.

We have read lots of different versions of the recent events on the web. Now this is the time that you have our version.

Threads and postings vanishing?

I had started e.g. this thread: http://letsmakerobots.com/5800mah-2s-25c-lipo-dagu-rover-5-power-distribution and there were a few answers to this and now they are all gone. What happened here? I can see it in the subsciptions but not in the forum anymore.

:-(

I know that there were more threads where I posted and more answers because the answers triggered emails. Many of these are missing now.

Wild Thumper woes with VNH2SP30 controller

I bought a 4WD Wild Thumper after building three different robots successfully with a mix of Raspberry PI and Arduino and the L298N motor controller which is obviously not up to the current draw of the thumper motors.

This lead me to the VNH2SP30 dual controllers. I have bought 2 both of which give a different amount of current in forward and reverse - whether used with a small salvaged DC motor (500mA typical draw) or with the wild thumper motors. I am using a 2 cell LiPo 20-30C.

Wild Thumper, progress but help/advice requested

Hi all,

I had a lot of trouble with motor driver boards and my Wild Thumper 4WD chassis - in the end I bought a more expensive motor controller said to handle 60A. I am controlling the paired (left/right side) motors by PWM signal and  it now drives forward/backwards/left/right etc.

Question about Dagu 4 Channel motor controller

As pointed out in
http://letsmakerobots.com/content/changing-pwm-frequencies-arduino-controllers
the frequency of the PWM for the motor controller might be an issue.

I am using this motor controller:
Dagu 4 Channel 5-12V, 2A Brushed DC Motor Controller
http://www.robotshop.com/en/dagu-4-channel-brushed-dc-motor-controller.html
actually it looks a bit different:

but I assume that both are the same.

5800mAh 2S 25C Lipo for Dagu Rover 5? Power Distribution?

I am setting up a Dagu Rover 5 plus 4 channel motor controller plus  Spider
robot controller plus Rasperry Pi.

The power supply from 6 NiMH batteries will not be enough for my Dagu Rover 5.
So I was looking for LiPos.
Found this one:
 ZIPPY Compact 5800mAh 2S 25C Lipo Pack
Capacity: 5800mAh
Voltage: 2S1P / 2 Cell / 7.4V
Discharge: 25C Constant / 35C Burst
Weight: 273g (including wire, plug & case)
Dimensions: 159x16x45mm
Balance Plug: JST-XH
Discharge Plug: 5.5mm Bullet

Motor control with PID and PWM

Working on adding encoders to my project and could use some resources/help on understanding how to code pulse width modulation (PWM) with Proportional Integral Derivative (PID) to control brushed DC motors. Any help would be wonderful. 

Robb

News About Product Reviews

We are happy to announce that LMR will be calling for reviewers at least twice per month with cool products and parts starting this month. Everyone month, we will provide two different types of products; One for more advanced roboticians and one for beginners. 

We are looking forward to having the community test products of different types as well as providing the chance to all; from experts to members fresh into robotics.

Terms and Conditions

Hi All,

arduino bootloader

hi every one 

kinda noob to this programing and stuff :) 

i have a small problem maybe some one could help me. Ive just bought 2 Deek robot mini boards ardunio clones but i dont have anything else to upload sketches into the borad other than arduino uno so i found tutoriel on google how to set it up.

taking out the atmel chip on the uno board 

and connecting

tx to tx mini

rx to rx mini 

reset to dtr mini 

gnd to gnd mini 

5v to vcc mini 

Search for fritzing parts

Looks like my posting vanished.
:-(

I am searching for the fritzing ( did not find them at
http://fritzing.org/parts/ or somewhere else) parts of my different robot
components.

I am looking for the following:
1) Dagu Spider Controller: I found some prototyp work here:
https://github.com/fritzing/fritzing-app/issues/2751
but it does not seem to be ready so I use the Arduino Mega
Proto Shield for the time being.

2) Dagu Motor controller:

TTL byte packet from PS2handle through Arduino to activate Maestro 24

Working on a hexapod and bought a Pololu Maestro24 for my hexapod robot. I want to be able to control it off-line using a PS2 handle running through an Arduino Nano to the pololu. I found Bill porters site that connects to The curious inventors site that has some good info like how to wire the PS2 handle to an arduino and the sample code needed to program the arduino to understand the PS2 handles commands. There is also a pololu\arduino library.

Ive compiled the sample code and uploaded it to my arduino and im pretty sure it works.

The Maestro the Arduino and the Decepticon, Wireless hexapod.

As some of you know ive been trying to complete a 3DOF Hexapod spider using a Torobot servo controller. Well i burned it out about a week ago and ive been trying to do some research on a more plausible choice of controllers so i can get the movement i want and all the extras.

I read up on the Pololu 32ch maestro. It seems they do have a sequencer but i can further develop thier script too. I also found some good information on using the PS2 handle with the arduino and there seems to be some libraries already compiled so that will make things easier.

CMPS11 vs MPU6050 - compass, gyro, accelerometers

Hi there, could anyone explain me the difference between CMPS11 and MPU6050? The first is marketed as Tilt Compensated Compass, the second "Accelerometer+Gyro".

I do realize the difference between 9 vs 6  degrees of freedom and do see that CMPS11 other than having internal compass has also Kalman filter hardware integrated, but in short, what should I buy and is there any benefit the MPU6050 can give me, that CMPS11 can not?

LMR, ...a sad fan from Germany

Dear friend !