cbrobot story

About the Creator

The Cardboard Robot was created by Ken Ihara for his 14-month-old son Alex.  Ken got his first taste of robotics while an assistant at the Harvard Robotics Laboratory in Cambridge, MA.  Ken has a degree in Engineering Sciences from Harvard University.

Ken developed and brought to market the PianoMaestro – an electronic USB device for learning to play the piano – in 2010.  the PianoMaestro has been featured on The New Inventors (Australian TV show), Gizmag and WIRED.

Ken currently lives in Melbourne, Australia.

Send an email to ken.ihara@thepianomaestro [dot] com
I will try to reply as soon as possible.


The Making of the Cardboard Robots

Making the cardboard robots was more challenging than anticipated.


The original plan was to have all the cardboard pieces pre-made in an industrial cardboard die cutting machine.   September and October was spent working with a cardboard manufacturing company in Palisades Park, New Jersey to get ready for a small production run.  I wanted to minimize the risk of logistics — instead of shipping cardboard from China, I thought it would be easier if I could fly home, rent a small truck and drive down a few hours to New Jersey to pick up the pre-made pieces myself.


Mother nature and Murphy’s Law had different plans for the Cardboard Robot.


My original 23-hour flight from Melbourne to Albany was cancelled due to Hurricane Sandy.   When I finally made it home a few days later, I was unable to contact the cardboard supplier for a whole week, as they had lost power and their phone connection.  When I finally did make it through, my fears were confirmed.   The facility was flooded, and they would not be able to produce the cardboard pieces in time.


With two weeks left, I decided to try to make the most of my trans-Pacific flight and make the 42 cardboard robots by hand. Thankfully mom and dad were around to help out, as we finished making all the pieces only hours before I had to depart back to Australia.   I learned a lot more about working with cardboard, and believe even more strongly that it is a wonderfully inexpensive, light and strong material for making cool things.  Some photos of the special tools we had to make for cutting and creasing the cardboard are posted below.


On Thanksgiving day, with our dining table surrounded by cardboard pieces and packaging material, my parents commented that it was the most memorable and enjoyable Thanksgiving in recent memory.   It was one of those increasingly rare occasions where we all worked on a large project together as a family.


Ken Ihara

December 2012




Transporting Cardboard



Rented Uhaul van with 200 sheets of 48″ x 48″ C-flute cardboard.   (We ended up using 160 sheets)



Cutting cardboard


After speaking to the guys at Home Depot and Lowes and a passing-by Milwaukee rep, I learned that cardboard is one of the most difficult materials to cut.  Cardboard has many fibers that crisscross each other in all directions, which will quickly dull power cutting tools.   Conclusion:  the box cutter knife is the best way to cut cardboard.


Above is a photo of a cutting frame used to accurately cut the large cardboard pieces into the needed sizes.  Notice the L-Square on the right.   The frame is made of 2×4’s and leans against the wall.   The cardboard rests against the two 24” x 48” pieces of plywood.


This cutter slides down the middle of the cutting frame.  The box cutter knife is screwed in.

Smaller frame for cutting angles


Cutting cardboard with bandsaw


Through experimentation we found that the bandsaw with a fine wood blade makes reasonably clean cuts through cardboard.


We made many jigs for cutting the cardboard at different angles.  To make the jig slide straight across the bandsaw table, we used a router with a triangular bit and 3/8″ square trim mouldings to make a linear guide.


This jig was used to cut the 800 tabs that were used in the two semi-circular motor drives.   Cutting all these tabs one at a time would have taken a lot more time!

This jig was used to cut the 60 degree angles for some of the triangular parts of the claw.   We also used another jig (not shown) to make all the circular pieces on the band saw.


Accurate locations of holes and features


For each arm piece, we made a template that we would be pressed against the cardboard blanks.



Screws were used to create holes in the correct locations.  These five screws indicate where to mount a stepper motor on one of the arms.




Once again we used the router to make triangular grooves where we wanted the creases.   3/8” square trim pieces were placed in the the groves, which provided the edge needed to create the crease.

Applying the right kind of pressure was challenging.  We built a press using a 4-ton vehicle jack and 2×4’s.  Results were mixed.


We made many adjustments to the press and made several other ghastly contraptions to try to apply even pressure to make the creases.   In the end, blocks of 2×4’s glued to slippers from Target worked surprisingly well!


Putting together the kits


Parts, parts everywhere


Some more parts…


The first kit all packaged and ready to go.




42 kits packaged and ready to go!!!