plz can u answer me where to put the 3 10 k ohm variable resistance and the gyro sensor
=( =( =( =( =(
i did it
i will upgrade later
no active post why
hi
is it possible for you to post the code so we can all enjoy? 
thanks!
We decided to install an Android device on the robot to control its balance instead of using an IMU. Here you can see the result:
charliesixpack:
You are correct that you do not need a Kalman filter. You also do not need an accelerometer. Check out the attached document for some of the myths concerning balancing robots.
It's pretty odd how they mention things like :
http://forum.arduino.cc/index.php?action=dlattach;topic=228028.0;attach=74470
"You can balance with just PID control but if you give the robot a push or have an offset in the gyro output you will cause the robot to fall."
And "In order to balance you need PID control plus positive feedback."
And "Positive feedback seems to be necessary. If you are balancing with a 'complementary filter' you are introducing positive feedback. If you are balancing with a gyro and an accelerometer you are introducing positive feedback. If you are balancing with a gyro and wheel encoders you are introducing positive feedback."
I disagree with most of his/her comments. Maybe even all of their comments.
I agree that you don't need a Kalman filter or an accelerometer, or wheel encoders for balancing a bot though. On the other hand, some of these features could enhance performance if you have a fast enough processor to handle things. But a number of things in that 'myth' pdf is quite misleading.
Their equation that comes after their sentence "PID control with positive feedback looks like this..." is erroneous.
I've recently been tinkering with a balance bot, and looking for information in the Arduino forums. Getting ideas about what others are doing to get their bots to balance really well, and dealing with noisy data and practical effects. Stumbled on this myth pdf, and thought some of the teachings in there are kind of misleading.