ROBOTC.net Blog  

Shaft Encoders, sometimes called a “rotation sensors”, measure the amount of rotation on the shaft, or axle, which passes through the its center. As the axle turns, the encoder “counts”. The shaft encoder measures 360 counts per revolution, and counts up for forward movements and down for reverse. By monitoring the axles connected to your robot’s wheels, the encoders allow you to control the overall distance the robot travels.

We’ve completed a set of tutorial videos in the VEX Cortex Video Trainer that will teach you in-depth how the encoders work, how to use feedback from the sensors to control the distance the robot travels, and how to use the ROBOTC Sensor Debug window to view those values in real-time.

To navigate to the videos, open the VEX Cortex Video Trainer, head to the Movement section, and choose Shaft Encoders. The 5 tutorial videos, along with helper documents, programming challenges, and additional resources are all available for free from that page!

We are working on making ROBOTC simpler and more beginner friendly! Here is our documentation for some new, simplified functions.  Each function can be used both with and without parameters!  (Everything is designed to work for the default REMBOT, but is customizable through parameters for more advanced users.)

Take a look and let us know what you think!

http://www.robotc.net/support/nxt/ROBOTC-for-Beginners/

NOTE: we have not yet released this version of ROBOTC to the public.

Thanks DiMastero for posting this!

For those of us who have encountered obstacles with our robots that always seem to derail our current path, you will appreciate this robot.

DiMastero has figured out a way to solve our woes dealing with unleveled ground.

Presenting… the Avoider/Climber robot…

Side View

Wheels

Side view 2

Sensors

Bottom

Backside

It’s programmed to first drive forwards, until one of the bumpers is pressed. It then stops the wheel at that sensor’s side, and spins the other one until it’s pressed too, making sure it’s at a 90° angle from whatever is in front of it. The next thing it does is check the US sensor. If the distance to the object is less than 9 cm, it knows the obstacle is too high to climb, goes backwards and turns approximately 90°. When the sonar sensor’s value is below 9 cm, though, the middle motor, with the claw, turns a full turn, to hop the bot onto the platform. The avoider/ climber can do all of that in any order, enabling it to survive in a labyrinth with different floor levels, for example. The programming was done on RobotC.

Below is a video of it doing it’s thing:

YouTube Direct Link 

I’m open to any questions or suggestions for improvement.

[Source: http://dimastero.wordpress.com/2010/11/11/smart-climber-and-avoider-robot/]