Lego Tank Cake

February 11, 2016

Using Lego Mindstorms to bring a cake to life


I was recently asked to bring a cake shaped like a tank to life for my newphew. Luckily I had an old version of the Lego NXT which I wasn’t using. The Lego NXT system is pretty awesome, it comes with a basic set of servos and sensors and you can then use a very simple drag and drop interface to program it.

The program

I initially worked by programming the Lego, below is the program which I used complete with sound effects. It uses a very simple of program, there is one motor which spins a bit to the left, a bit to the right and then plays a sound. The program looks like the following:

Mindstorms program

This simple behviour looks like this:

The cake board

We need to construct a special cake board so we were able to switch the cake on and off. This envolved cutting a hole out of a piece of MDF so we could see the screen and activate the buttons.

Building the cake

The cake is made from a simple sponge which is in 3 layers. Each layer has a hole in the middle to fit the Lego, which was encased in a box. The turrent is constructed out of rice crispys and marshmallows with the Lego cast into them. Then it’s a simple case of mouting the turret on the top and decorate.

Unfortuantely under the 3 layers of cake you can no longer hear the tank sound.


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