Making Robots from Scratch

An Inside Look at Bringing PLEN Cube to Life

PLEN Cube is a cute, powerful, portable robot that works with IFTTT.

When it comes to hardware innovation in 2017, there are a couple buzzwords that get circulated. IoT. Voice-activated. Open-source. And you better believe that our latest product, PLEN Cube, has all that. But it all started with other inspirations:

Anime. Cuteness. Personality. Portability.

Retro? Perhaps. But we think personality + ease of use for the first time robotics consumer is our special sauce.

Our team at PLENGoer Robotics has a history of making robots with expressive motions and character. The PLEN2 was the world’s smallest bipedal humanoid robot (and, as far as we know, the only robot that can skateboard). Our community of users is broad and diverse — advanced developers to amateur tinkerers can customize the PLEN2.

We began the PLEN Cube with a similar vision: make it cute, unintimidating, and powerful. Here’s a peek at our development history — from idea to our Kickstarter campaign (live now until April 22) — to the prototype fine-tuning were doing now.

Our Concept: Portable Robots

Right now, you might think of highly specialized robots in warehouses or operating rooms. But more and more, robots are entering our everyday lives. We’re based in Japan, where robots are already taking care of our rapidly aging population, serving pizza, and performing in public spaces.

We started with a thought: it’s just a matter of time until robots become commonplace. But in that case, they can’t be big and bulky. What if they could fit into the palm of your hand?

An early prototype of PLEN Cube’s outer shell.

That’s when we had the idea: a portable robot.

Think of the computer. Just 50 years ago, they filled entire rooms. Now they fit in the back pocket of your jeans. We believe the same is true of robots. Robots won’t be relegated to special occasions — they’ll be indispensable parts of our lives, controlling appliances in the home, keeping your schedule on track, taking a picture when you’re out and about, and even serving as a friend.

Designing for Functionality and Cuteness

We started with design first.

In order for people to use our product, it has to be fun and blend into people’s lives.

You can have the best technology in the world, but that won’t matter if the product is cumbersome, ugly, or dull.

Like most projects, there was lots of trial and error. At first, we built a snowman-shaped robot called PLEN.Q. We even got as far as creating a moving prototype.

A moving prototype of PLEN.Q

Though the PLEN.Q was certainly very cute, it just wasn’t practical. It wasn’t stable enough to stand on its own, and the sphere shape created too much dead space where parts couldn’t be placed. And when you’re looking for portability, every millimeter counts.

Early sketches of PLEN Cube

Then our CEO Natsuo then had a eureka moment and sketched it on a piece of paper. A simple, clean dice shape. This was it. The cube was a familiar shape that could fit into your life simply and naturally. It could have personality and character while it was performing tasks, but practically disappear when it wasn’t in use.

And so PLEN.Q became PLEN Cube. And we really got to work.

Moving like a living companion, not a machine

We had the cube shape. And we knew it had to be portable. The next step was showing personality. It was important to us that PLEN Cube feel like a living thing rather than a machine.

We had the cube shape. And we knew it had to be portable. The next step was showing personality. It was important to us that PLEN Cube feel like a living thing rather than a machine.

Our designers sketched hundreds of options. Our goals sometimes felt at odds with one another. On one hand, we wanted the PLEN Cube to portray nuanced expressions, which required many motors. On the other hand, we wanted to make the PLEN Cube as small as possible.

Eventually we arrived at the design you see today: a detachable “head”, a top-facing display, a camera, and a whole lot of features packed into its 3”x3” body.

Discreet when you need it to be, functional and cute when you’re interacting with it

The cube shape allows the PLEN Cube to be stable and discreet. But when it’s performing actions or dancing … PLEN Cube unleashes its personality. Here’s a video of an early PLEN Cube prototype:

An early movement prototype — before we added the display and internal hardware.

Being Selective About Internal Hardware

When we got the basic design down, the next step was internal hardware. Since we have limited space, we had to be very selective about the hardware we wanted.

We chose Intel Joule because it’s a tiny powerhouse that offers a world of possibility when it comes to robotics, computer vision, IoT, and high-end edge computing.

Using a microscope to solder onto the circuitboard
All that has to fit into where?

We also studied structure design and made physical modifications to improve the precision of speech recognition, face recognition, and motion.

Holding the camera and testing our facial recognition technology

As we refine our prototype and get it ready for mass production, the biggest challenge is positioning necessary functions in a small space.

It’s a bit of a puzzle — hardware needs to placed in the optimal area for performance, and also fit into a 3-inch cube. We have to think about weight balance, heat control, microphone placement, and lots more.

Our prototypes are really shaping up nicely. Our parent company, GoerTek is a world leader in electronics manufacturing, and we’re constantly collaborating with their experts.

One of PLEN Cube’s first panoramic photos: office chairs!

The Future

Now that we’ve beat our Kickstarter goal (thanks to our incredible supporters!), we’re in hardcore development mode. This is how we describe PLEN Cube on our Kickstarter:

PLEN Cube is a portable robot that can consolidate your devices and web services, making them simpler to use and automate; capture moments with a smart camera that tracks your face and motions; and complement your life with hands-free activation and customization options.

This description captures PLEN Cube’s technology. Every day, we wrangle with development challenges. Yet we always try to remember our original goals.

Make PLEN Cube compact yet powerful.

Make it fun and expressive.

Make it a true robot companion that can help you anywhere, anytime.

As of today, we’ve raised $85,519 on Kickstarter. This October, will ship PLEN Cubes from our Osaka, Japan to makers and tinkerers all around the world. So far, we’ve seen support from the United States, Australia, Ireland, Italy, Belgium, Norway, Russia, and many more.

Check out our Kickstarter to learn more about PLEN Cube and pre-order your own. The campaign runs until April 22!

Enjoyed this post? ❤ it & share.

Stay up-to-date with us by signing up for our email newsletter at