Prolific creator [Martin Raynsford] recently created a plus-sized edible version of his laser-cut Marble Machine for a Cake International exhibit and competition; it seemed simple to do at first but had quite a few gotchas waiting, and required some clever problem-solving.
The original idea was to assemble laser-cut gingerbread parts to make the machine. Gingerbread can be laser-cut quite well, and at first all seemed to be going perfectly well for [Martin]. However, after a few days the gingerbread was sagging badly. Fiddling with the recipe and the baking was to no avail, and it was clear [Martin] needed to find something other than gingerbread to work with. After experimenting, he settled on a modified sugar paste which kept its shape and dried hard enough to work with. (While appearing to stretch most people’s definition of “cake” past the breaking point, the category [Martin] entered in the competition allows it.) The parts were cut by hand using laser-cut wood parts as a guide, then finished in a food dehydrator overnight.
The next problem was how to create the large spiral which forms the main ramp. The answer was to laser-cut a custom support structure that supported the piece while it dried out, and doubled as a way to transport the piece safely. High stress points got extra layers cemented with sugar glue, and some parts were reinforced internally with strands of uncooked spaghetti. Everything was sealed with an edible shine, which [Martin] says acts as a kind of varnish for cakes. A video demonstration is embedded below. Continue reading “Problems that Plagued an Edible Marble Machine”→
Stringed instruments make noise from the vibrations of tuned strings, using acoustic or electronic means to amplify those vibrations to the point where they’re loud enough to hear. The strings are triggered in a variety of ways – piano strings are hit with hammers, guitar strings are plucked, while violin strings are bowed. Meanwhile, [Martin] from the band [Wintergatan] is using marbles to play a bass guitar.
[Martin] starts out with a basic setup. The bass guitar is placed on the workbench, while a piece of wood is taped to a tripod. The wood has a hole drilled through it, and marbles are dropped through the aperture in an attempt to get them to land on the string. Plastic containers are used to easily alter the angle the bass guitar sits at, relative to the bench, while an acrylic guide sits around the string to try to guide the marbles in the desired direction. These guides are important to make sure the marbles hit the top of the string, and bounce cleanly in the desired direction afterwards.
The initial setup is too inconsistent, so [Martin] places a notch in the wood and builds a lever system to hold the marbles and then release them in a controlled manner. [Martin] then checks that the system works by analysing footage of the marble drop with slow motion video.
The video covers the CAD design of an eight-slot guide so the four strings of the bass can be played more rapidly than in their previous build. Two guides per string allow each string to play two notes in quick succession without having to worry about marble collisions from playing too quickly.
Marble machines are the kind of useless mechanisms that everybody loves. Their sole purpose is to route marbles through different paths for your viewing pleasure. They can be extremely complicated contraptions, and sometimes that is the precisely the point. However, even a simple mechanism can be delightful to watch. [Denha] just uploaded his latest creation, using a spring as elevator and a simple zig-zag path.
The construction is relatively simple, a spring with the appropriate pitch for the steel balls size is used as an elevator. The spring is driven by a small electric motor via a couple of gears, and a wooden zig-zag path for the marbles lies next to the spring. The marbles go up with the spring and return in the wooden path in an endless journey.
We believe that a serious hacker should build a marble machine at least once in their life. We have posted several of them, from simple ones to other more complicated designs that require careful craftsmanship. [Denha]’s Youtube channel is full of good ideas to inspire your first project. In any case, watching a marble machine at work is quite a nice, relaxing experience.