VEX EDR terms?

Ok so I just wanted to familiarize myself with VEX key terms before I start designing my robot. Would appreciate if you could give an easy, concise definition of the terms below:


Snail Bot

Odometry wheels

Speed cartridge

Indexer - A mechanism, typically a roller, which spins in a certain direction to hold an object in place before an ejector such as a flywheel or conveyor belt. When ejection time arrives, the indexer spins in the opposite direction so as to release the ball into the ejector.

Snail Bot - A style of robot used for change up in which balls are intaken from the bottom of the robot, and ejected at the top of the same size, named so because the ball’s bath resembles that of a snail.

Odometry Wheels - Unpowered wheels mounted with encoders which track a robot’s movement relative to the ground. They are often suspended such they they always touch the ground regardless of a robot’s tilt.

Speed Cartridge - One of three cartridges used in V5 motors: the Torque Cartridge (red, 100 RPM), the Medium Cartridge (green 200 RPM), and the Speed Cartridge (blue, 600 rpm).


Indexer is used for many things. For example when using a fly wheel it is a roller that makes sure the balls don’t get to the fly wheel until you want it to. Snail Bot can be easily described just by looking at 99999v’s cad. Odometry wheels is a wheels that has sensors to make your autonomous more accurate (with no motor, just sensors). And a speed cartridge is something you can buy from vex, put in a more and have the rpm higher or lower. In this case a speed cartridge would be 600 rpm. The standard you get just with buying a motor is 200 rpm. And there is a torque one that goes 100 rpm.


Dang it you did it right before me.

And better too.
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So a drivetrain wouldn’t consist entirely of odom wheels since they aren’t powered?

Definitely not. The purpose of odometry wheels is to create a non-slipping wheel surface. The advantage of using odometry wheels over the internal motor encoders is that drive wheels often slip on the ground, providing an inaccurate reading of their rotation. Odometry wheels eliminate the possibility of slippage.

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a tracking wheel (odom wheel) is just an unpowered omni wheel with an encoder that you mechanically press into the ground to have an accurate measure of distance traveled without having to worry about wheel slippage.