Knock Knock is a clever Arduino-controlled calculator toy, designed for small children. The user knocks out a calculation on the surface — addition, multiplication, subtraction, or division — and Knock Knock will spit back the solution, in the form of knocks, of course. Created by Switzerland designer Khalil Klouche, Knock Knock is brought to life with an Arduino, contact microphones, and solenoids. It’s a fun idea for a toy, but good luck trying to use this in secret during a “no calculators” test at school!

[via the Makeshift newsletter]

Laura Cochrane

Laura Cochrane

I’m a DIY editor at Instructables and I used to be an editor at MAKE and CRAFT. I like hiking, biking, rock climbing, and etymology.

  • mark

    great innovation! it makes learning more interesting and easy for kids at early age.. it develops good grasps of maths while enjoying it.. there are some projects also that’s intuitive to learning, but i find this best since it can be used/played as early as 2 year old children.. thumbs up to this.. awesome!

  • Brandt

    I would love to see a schematic for this!

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