MIT Student Builds Awesome Working Mario Kart, Documents Process Every Step of the Way


A self-described electromechanical hobbyist and MIT student named Charles Guan is the mastermind behind the Chibikart, a motorized Mario Kart-like vehicle built from scratch.

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On his blog, Charles states that Chibikart took him a total of three weeks to build, "from [announcement] to first ride test," which seems like just absolutely no time at all.

I reached out to Charles via email, curious to find out how much a project like this would cost a person...

The battery pack was an exclusive that he was given at no cost, but it's not on the market. "An equivalent lithium ion battery of that size is about $250 to $400 depending on quality/grade. ($250 for two model airplane batteries, and for a vehicle grade pack.)"

"The motors have about $250 of materials and machining time put into them," —which, with a total of 4 motors, is another $1k of expenses— "but it's not a cost I paid directly," Charles explains, "because I already had many of their parts." Factor in about $300 of "direct frame material and hardware costs" and a scratch estimate would put the cost to build the Chibikart at about $1300. (With the caveat that the battery cost isn't really known.)

Building a Chibikart from scratch, if you don't already have some of these parts, could set you back as much as $1750 (factoring in the higher-cost equivalent lithium ion battery).

He documents the whole assembly, tweaks and setbacks and all. So I fully expect a fleet of copycat Chibikarts to appear in the coming months. Which would be great. Especially if someone built one for me.

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Chibikart Specs

• Frame size: 34" by 18"
• Motors: Custom-wound and packaged direct drive hub motor, 300W peak each*
• Wheels: 100mm 87A skate wheels
• Battery: 32v 9Ah lithium iron phosphate pack
• Controllers: 350w-class Mysterious Chinese Sensorless e-Bike Controllers ("Jasontroller")
• Top speed, theoretical: 26mph (voltage & motor RPM/V & wheel diameter)
• Top speed, realistic: 21mph**
• Actual top speed: To be determined.
*30 second "peak" rating at 20 amperes
**Factoring in conservative estimates for air drag, and motor resistive losses at-speed, smooth and level ground assumed.

[EqualsZero via BuzzFeed]

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Illustration for article titled MIT Student Builds Awesome Working Mario Kart, Documents Process Every Step of the Way

DISCUSSION

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Methylsulfonylmethane

I watched the video before reading the article and was stunned at the apparent power-to-weight ratio of his little cart. After watching I skipped straight down to the specs: "32v 9Ah lithium iron phosphate pack"

"Aha" I thought to myself "It contains unobtainium. That figures."

Indeed, Ms. Oswaks confirmed as much when she mentioned that the battery pack is "not on the market". That is an understatement. This ludicrously tiny go-kart may be adorable in it's proportions, but do not be fooled: it is absurdly sophisticated in it's construction. Even with the designer's generously detailed documentation of the build process, very few people have the skills and resources to duplicate the thing. The custom-machined in-wheel-hub electric motors are especially pimptacular pieces of kit. This brings me to my point:

"Building a Chibikart from scratch, if you don't already have some of these parts, could set you back as much as $1750"

This statement is patently ridiculous. A number that stands at double that figure is far more realistic, but still low if you ask me. You could certainly build a tiny go-kart for $1750, but it would be nowhere near as elegant and high-performance as the original chibi-kart. Replicating those motors alone could chew through at least $2000 as they require high-end machining work that the average person simply doesn't have access to. You could use off-the-shelf parts, but you would then end up with something bigger, heavier, slower and compromised in general.

Just because the chibi-kart is adorable and was turned out in three weeks doesn't mean it would be straightforward or cheap to replicate. To suggest as such is a discredit to the original designer. It's design is sophisticated and the manufacturing is incredibly refined. A huge amount of the value invested into the chibi-kart cannot be represented with dollars as it is made up of the talent of it's builder.