MOSS Robotics Toy Review: The Easiest Way To Build Your First Robot

MOSS Robotics Toy Review: The Easiest Way To Build Your First Robot

When reviewing a building toy it’s impossible not to make comparisons with Lego. Not only are its bricks able to build everything from dinosaurs to X-wings, Lego also offers robotics sets that have been used to make some truly impressive autonomous creations. In that latter category, it finally has some competition.

The folks at Modular Robotics are certainly facing an uphill battle with their MOSS robotic building sets. But unlike the countless Lego knock-offs already on the market, the company has come up with a radical new way for enthusiasts to build robotic toys. And it’s how the MOSS sets differ from Lego that makes them an alternative worth considering.

What Is It?

MOSS is a modular building toy that allows anyone to easily build semi-intelligent robotic creations without the need for a computer, programming know-how, or any prior experience with building bots.

It may sound similar to existing robotic building sets, but the components that make up the MOSS sets connect to each other using metal ball bearings and magnets, instead of the traditional plastic interlocking studs. MOSS introduces a radically new way to build where the connectors not only hold components together, but also allow them to bend, move, and pivot, all depending on how they have been attached to each other.

What’s that mean in practice? Since all of the ‘programming’ is dependent on how you’ve connected the various MOSS components, experimentation and trial and error is made easier and more enjoyable. The process is part of the fun.

Why Does It Matter?

Lego is the undisputed king of building toys, and its Mindstorms robotics sets have allowed people to come up with some fantastic creations using just plastic bricks. But Mindstorms also has a steep learning curve, requiring users to become familiar with its included graphical programming language, and to have access to a computer.

The MOSS sets allow you to build semi-intelligent robots right out the box, without having to install software or connect them to a PC. And that makes them far more accessible to children, or anyone who wants to start dabbling in robotics. It’s also a clever way to introduce kids to engineering concepts. By being able to just build and test a robot without having to keep hopping over to a computer to update its programming, it makes the creative process far less frustrating.


There are two main building ingredients that go into any MOSS creation: a set of 19 different modular components that each have specialised functionality and capabilities including motors, sensors, input dials, wheels, cables, connectors, and even Bluetooth. And a mountain of uniformly-sized metal ball bearings that hold the creations together.

All of the components are based on a simple cube design, which makes connecting them all together incredibly easy. And depending on their colour, the various faces of each cube provide different functionality. Green faces pass along power, red and brown faces pass data in and out, and blue faces serve as pass-throughs for either or.

Some of the more specialised MOSS cubes also feature faces that work as sensors to allow creations to interact with their environment. The proximity sensor can detect and trigger an action when the robot is near a wall or other obstacle, the light sensor is able to react to a bright source of light like the sun or a flashlight, and a microphone can detect abrupt changes in ambient noise, like someone clapping. There's even a cube with a physical knob on one side that allows a robot, or a specific component of one, to be controlled manually.

But it's how all of the components are designed to connect together that makes the MOSS sets unique among all the other building toys already on the market. The corners of all of those modular cubes feature magnet-backed indents that the included metal ball bearings connect to.

Putting a ball bearing in all four corners of a cube allows that side to fully connect to another cube, and then pass along power or data.

Use only two ball bearings to connect a couple of cubes, and suddenly you've created a free-moving hinge. Limit the connection to just a single ball bearing, you're left with a connection that's free to move in almost any direction.

And that's what makes the MOSS sets really stand out. You're not just building a robot for the sake of building it. How you build it plays a big part in what it's able to do.

Using It

Building with the MOSS sets is almost as easy as building with wooden building blocks. The only difference is that everything is held in place using those metal ball bearings. What can be tricky, though, is knowing how you connect the various modular cubes, and in what order, to make your creation behave how you want it.

Once you've memorized what the various coloured cube faces do, it becomes a little easier to ensure that a sensor cube down the line has the power it needs, or that it's properly passing data onto a motor or other component. However, troubleshooting a creation can be a little tricky sometimes, because if a cube is buried amongst other components, determining which of its faces is making a connection often requires a bit of temporary disassembly.

The MOSS sets aren't designed to let you build a human-sized robot butler that can make coffee in the morning; that's just not going to happen. They're instead designed to let you build simpler creations that can react to their environments. The set we tested included instructions for building a rolling robot that used a proximity sensor to follow your hand, without getting so close that it would crash into you. And models that demonstrated the unique ways the MOSS robots could move across a floor including mounting the wheels flat against the ground which would cause the creation to shimmy along like a lizard.

As a result, the MOSS sets aren't going to wow you with functionality; they're really designed to show kids that science and technology can be genuinely enjoyable, and that the experimentation involved in building a semi-intelligent creation is as much a part of the fun as the end result.


When it comes to building toys, particularly sets that let you build your own robots, the MOSS kits feature a unique design and approach to building that makes it very easy to bring a creation to life. Once you've figured out the proper way to connect the various components to share power and data, you're all set. There's no software to install (outside of smartphone apps that add to the functionality), no programming languages to learn, and no having to continuously upload software to your creation every time you want to change its behaviour.

That ease of use certainly results in some limitations when it comes to how complex and capable a robot you can build. But pushing the limits of the components at your disposal ends up being incredibly satisfying. And there's a wonderful sense of achievement when you finally figure out how to make your robot do something neat.

For kids, at least those old enough to be trusted with a box of small metal ball bearings, it's the perfect way to introduce them to robotics. The MOSS sets have a similar appeal to traditional wooden building blocks, where kids can immediately go to town building castles or forts without the need for elaborate instruction manuals or even access to a computer. But it takes things one step further adding interactivity, and secretly getting kids to learn about concepts they might otherwise think are boring.


One of the things that has made Lego so incredibly popular is that its seemingly endless variety of pieces lets kids build highly recognisable creations, from like space ships to sports cars. Unfortunately, the same can't be said for the MOSS sets. The various components put functionality first, and as a result it's usually impossible to figure out what a creation is supposed to be, or do, until it's powered on. With enough effort you could create something vaguely reminiscent of an animal, for example, but you'll often be trading functionality, or wasting valuable components, to get it to that point.

There's also a bit of a learning curve when it comes to building a robot that functions as you envision it to. Not having to hop over to a computer to modify and then re-upload a program is certainly one of the MOSS's biggest advantages. But it also means you'll often have to put some real thought into how to accomplish a motion or action using the limited components you have available, and re-build a creation from the ground up a few times to perfect it.

And while the use of metal ball bearings and magnets as connectors is incredibly innovative and introduces new ways to build and introduce motion into a robot, it also means your creations are a little on the fragile side. If you build a robot that skitters around on the floor and happens to crash into something because its proximity sensor didn't see it coming, the odds are you're going to have some rebuilding to do. And sometimes even safely holding a larger creation while you add components without it falling apart can be tricky.

Finally, since these are the first MOSS sets to be made available to the public after Modular Robotics' successful Kickstarter campaign, it unfortunately means they're also a little on the expensive side. The base set, the Zombonitron 1600, which is what we reviewed, will set you back $US150 for just 16 different components.

And the full set, the Exofabulatronixx 5200, which comes with 52 components, is a hefty $US480. As the company sells more and more of the sets and the demand increases the economy of scale will certainly kick in and bring the prices down. But for the time being they're an expensive investment if you're really hoping to build something cool.

Should You Buy It?

When it comes to building toys like Lego or the MOSS sets the question is more "should we start buying it," because you never really only buy just a single set. Part of the fun of building toys comes with constantly adding to your repertoire of parts and slowly expanding the types of things you can create. You're actually buying into an entire line of toys rather than just a single set, and at the moment that's where the MOSS sets are limited.

It makes sense, though, since today is actually the first time anyone can buy the MOSS robotics sets. When Lego was first introduced it was incredibly limited too, so it's not necessarily a bad thing. As Modular Robotics continues to develop the MOSS line, it will almost certainly add new components, capabilities, and functionality that will keep improving the replay value of the toy.

And given how the MOSS building sets are at launch, there's definitely room for Modular Robotics to carve out a healthy niche for itself. It's best not to think of the MOSS sets as a Lego competitor, but as a building set that provides a different experience for kids. It seems focused more on the building process itself, and the trial and error of bringing an original robotic creation to life. Instead of just using a prepackaged set to recreate something using plastic bricks -- and that's what makes it wonderful.

If you approach it as a learning toy, and as a way to get your kids excited about science and technology, then you'll certainly get everything you're hoping for from the MOSS sets. For schools they're a must-have teaching tool when the subject of robots comes up -- because science is far more entertaining when you get to experiment.

MOSS Robotics Building Toys
Zombonitron 1600 - 16 modular components - $US150
Exofabulatronixx 5200 - 53 modular components - $US480