Imagine any chain-fed gun, then wrap the ammo around it front to back.
About this creation
The basic idea originally came when I was trying make a chain-fed gun and had problems with storage/feeding, which is when I decided to just wrap the whole chain around the gun itself.
The concept is really quite simple. Each time the touch sensor is pressed, the feeding motor turns one sixth a rotation to position a new tread link, then the firing motor turns half a rotation to fire one pin. Since it alternates firing left and right pins, there are an odd number of links so that all the ones it misses on the first pass are picked up on the second.
As you can imagine, the idea of "shooting" pins by just poking them from the back really isn't very effective... I was really just trying to see if I could make it feed and shoot properly with the belt wrapped from front to back like that.
It was purely accidental, but it ended up being pretty modular. The last picture shows the whole thing deconstructed into chunks.
I guess thats about it. Enjoy!
From the side
Without the belt
The feeding mechanism detached
Close up of the feeding mechanism gearing.
From the top without the feeding mechanism
The frame that holds the belt in place while the pegs are being shot as viewed from the top
The firing pins with the belt frame removed
The central portion with feeding mechanism and NXT removed
A better view of how the firing pins are actually moved