Auto Indexer

Hi all i need some help how is it possible to do something like this mechanically and programming wise?


this topic explains how they did it.


What we did is create a two stage roller system that when we spin the bottom rollers it would index the ball and then when we activate the top then we can score. We don’t have the front intakes on yet, but you get the idea. Here is the link to the video:

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The benefit of the other system though is to have more grip on the balls and to only put one ball in the goal at a time if you want.

Hi i’m the one that recorded this video

So we have 3 rollers powered on 2 motors, the top roller runs on a single motor (1000 rpm) and the other 2 are powered with 1 motor (600 rpm)

We also have 3 line trackers on the robot at the spot where we want our balls to be, let’s nickname it top, middle and bottom. When a ball are at the spot, the line tracker reading will lower which is how we detected if the ball are there

When all 3 readings are low, the rollers + intakes will run continuously at full speed

If (the top line tracker reads high)
stop the top roller from running (you might have to lower the other roller’s speed if your first ball gets pushed out of the bot)

If (both the top and middle line tracker reads high)
Stop all rollers but keep the intake running

If (all the line trackers read high)
All 3 balls indexed, stop intaking balls

That’s basically how the code works, but here are something to note: The line trackers are somewhat sensitive to lighting conditions, our auto indexing worked at our summer building spot but ceases to work at school, where it is a lot brighter. Tune your line tracker expression carefully to make sure it can work at different spots, you might have to redo the constant at a competition where lighting conditions are different. Also, it seems to work slightly better with blue balls than red maybe because blue is darker

Right now i might want to experiment with using limit switch in stead of line tracker since it is not dependent on lighting, hopefully the outtaking won’t destroy the limit switch tho

btw we can also do that too due to how our code works, as shown in the video