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What is it?
Short story? Its a TANK! That fires cannonballs! And it collects it's own ammo, no more getting up to refill it manually! This is part of an ongoing project of mine to make the most compact, cost efficient, and functional tank design possible. Be sure to check out the videos below to see it in action!
Whats so special about this tank?
What sets my tank design apart from most is it's ability to collect it's own ammunition by driving over it. In addition, it's ammo collector, cannon, and driving are all powered by a mere 2 motors. This allows up to four tanks to play at once because each tank uses only one of the four power functions frequencies. Because it uses only two motors, it needs far fewer expensive parts (it cuts the price down by more than 30 bucks), making it very affordable compared to the expensive $350.00 USD Mindstorms EV3 system. By my estimates, it cost me less than $120.00 USD to produce.
How it works
If you didn't watch the video, or want a better explanation than the video provides:
The left stick controls forwards and backwards on the left tread, and the right stick controls forwards and backwards on the right tread. Both treads/motors are rigged to the cannon and ammo collector by ratchet mechanisms.
Whenever a tread rolls the tank forward, the sweeper spins to grab ammo that has been guided by the tank's bumper into the collection channel. The sweeper pulls it up into the collection chamber at the top of the tank, which feeds it into the firing mechanism. Because the sweeper is attached to the motor by a ratchet, if it drives backwards on either side, it comes loose from that motor so it doesn't lose the captured ammo. If one side rolls forward and the other drives backwards, the sweeper continues to roll forward because it comes loose from the side going backwards but is still attached to the motor driving forward.
Likewise, the cannon is operated by driving backwards. Once you have rolled over and picked up ammo, you do lose some maneuverability because trying to drive backwards will begin launching the cannonballs one by one. If your target is not in front of you, you can line it up by driving forwards on just one side or the other of your tank. It will effectively pivot left or right, and even do wide U-turns so you can turn around to face a target behind you.
Please understand that since this is a functional creation instead of a decorative one, there will probably be changes to the final design as I seek to improve it and reduce the end cost to the buyers. I have chosen to use very minimal armor on the design presented so supporters can see and understand the inner workings better. Ill probably leave any additional decorative aspects up to the design team at The LEGO Company.
The deign also works best on carpet, so I'm hoping The LEGO Group can be convinced to add snap on rubber grips for the treads, or other elements to help the tank function better on hard surfaces.
I was not expecting my previous project to succeed based on my very basic proof of concept that lead to this greatly improved version. That was always a placeholder for this design, but as I leaned from my first Ideas submission the original design becomes the posterboy for the entire project, so it did not end well. Still, I had more than 20 supporters who I am very thankful for. As small as that number is, it was encouraging that even with my bad marketing and crummy looking project, people were still interested in the concept that would turn into the design I present to you now.
I also want to thank the people at the fan convention "Brick Universe" who gave me room to set the tanks up, and the people who played with the tanks and allowed me to collect important information for the newest design.