The Makeblock mBot Add-on Pack-Six-legged Robot V1.1
The makeblock robot is an arduino technology robot. It can be controlled with a supplied controller, or operated from any of several different kinds of computing devices (such as your cell phone) using an app. It can be programmed using the Arduino interface (from a Mac, Windows or Linux computer), but the robot comes with built in capabilities so you won’t need to do that to operate it. Note that the app-based controls provide more functionality than the hand held IR control.
But here we are talking about making that robot into a six legged insect with an add on package.
The add on package consists of the leggy parts of the photograph above. With this add on installed, the robot walks instead of rolls on wheels.
I love the Makeblock Robot and this is a great add on, but before you start investing in this system you need to know a couple of things.
Makeblock itself makes well designed and interesting robots and add ons, but they also produce several slightly different versions of everything they do. They all seem to work fine but there are many differences you will want to track. For instance, when buying a robot make sure you get one with bluetooth, because you will enjoy controlling the robot with your phone, where you will have more options than with the supplied IR controller. When choosing a leg upgrade, there are several options, though I think they all have the same basic parts. Each expansion pack allows you to make a six legged robot (the beetle robot) or a mantis robot, or a crazy frog robot. The kits I know of are:
I would go for the cheapest one, which at the moment, is this one
The basic idea is this: The main back wheels of the mBot robot serve as cams for a set of levers. To get a six legged robot, the first lever is attached off center to the wheel, and thus acts like a piston as the wheel rotates. This then drives all the other levers in a series of crude step like movements. The other variants use a similar principle.
Tips and hints for building the mBot legged robot extensions:
This is a DIY kit. Therefore, the manufacturers have less than the usual interest in keeping their product exactly the same for every iteration. This probably contributes to the plethora of seemingly similar but maybe slightly different versions. So, the first hint is to look at the pictures and descriptions closely to see if you can figure out exactly what you are getting, and then, don’t expect the instructions to necessarily exactly match the product. They usually do, but beware.
If something doesn’t seem quite right, check the instructions to see if you screwed up. Whether or not you screwed up, remember: DIY project. Fish some additional bits out of your box of extra parts, figure it out.
The biggest limitation of the robots, especially the six-legged version, is the surface on which they are walking. I have two suggestions that may allow them to be able to turn on a carpet and to keep traction on slipper tile. First, maybe add length to the legs so the thing rides up higher. Second, add feet. Feet that provided a bit more traction would help on tile. Perhaps a simple wrap of electric tape will do this. Feet that are flat attached to the bottom of the legs, like little snow shoes, should both increase traction and allow better turning on shag carpets. If you are going to have this robot chase around your cat, you are going to have to handle a variety of surfaces. We are playing around with some of these ideas.
The kit comes with what are called “lock nuts.” But really, they are “hard to screw on nuts.” They are designed to not unwind themselves to fall off this highly energetic device. Two hints will make their use more effective.
-use a socket from a socket wrench kit to hold the nuts when you are screwing in the bolt. This will work better then the little wrench the kit supplies, or your fingers.
-there may be some places where the instructions don't tell you to use a lock nut, but you will want to anyway. You will discover these when the nuts start falling off as you use the robot.
In the six legged build, shown at the top of the post, notice that the wheels do not have their tires. Take the tires off. In our kit, the instructions did not say to do that.
Instructions for making the Mantis, and Crazy Frog configurations
The six legged adapter kit allows you to make three configurations. The most complex one is the Beetle, which uses six legs. The other two, Crazy Frog and Mantis, are much simpler.
Instructions are provided to make the Beetle. To make the other two, look at the back of the box and, well, DIY!
Notice that with the Mantis, I think you keep the tires on the back wheels. With the crazy frog, you take the tire off.
Have fun!