I have decided to post a number of Lego MOCs to my blog, so readers can see what I sometimes get up to.

While I have been playing around with building a Ball Contraption - or more to the point, trying to coach the club kids into building some, I identified the need for a good ball hopper.

If you look at these first photos - you can clearly see that with a simple hopper, Lego balls tend to catch on the bricks, and you get jams. This was how I explained the purpose of the device to the kids at the club.

So I thought about building a mechanism to stir the balls My inspiration came from seeing the stirrers used in the belt lift components in RokenBok. I created the basket itself, and the actual mechanism to turn the stirrers - as seen from this underside shot.

I then experimented with a few different types of stirring arm - I tried (my initial design) the large Lego classic space radar dishes - http://peeron.com/inv/parts/4285b. These didn’t seem to work too well. I tried a few different ideas, and settled on the studless 3 bladed liftarm piece http://peeron.com/inv/parts/44374 - which was most effective.

In the next shots - you can see the counterweighted mechanism for keeping the door shut. This was because I was considering using it with a simple lift mechanism.

More shots at the gallery

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