One of my lab-mates expertly assembled our MakerBot 3D printer a few months ago. I’m not quite sure what happened next, but last week the MakerBot was placed on my desk with the indication that it needed to print within the next few days. I had heard rumors that the stepper motor drivers were blown. I also knew that the Plastruder thermistor was not working. And the Plastruder had never actually extruded anything. It turns out that pin 12 (half step enable pin) on two of our stepper driver boards was shorting to ground. The symptom of this short was an extremely hot voltage regulator, and by association the large capacitor next to it. The quick and dirty solution was to cut this pin. With both of our motor drivers this was all that was needed to bring the MakerBot axis’s back to life! It is important to check and make sure that MakerBot still moves 1cm when you tell it to move 1cm. Ours was now moving twice as far as we wanted because half stepping was no longer enabled.

The solution to this was different for each driver. On the Z axis all I needed to do was solder a pull-up resistor to pin 12. The Z axis was 1/2 stepping again but this didn’t work on the Y axis. After considering updating the firmware to compensate for the full step, we agreed to swap out the stepper driver chip. Eric’s soldering skills had this done in no time. Once again the MakerBot was precisely stepping in all directions!

To fix the dead thermistor, the lab had tried several things including re-wrapping the Plastruder head and replacing the thermistor itself. I had a feeling that the analog to digital converter pin was blown on the AVR, and I knew from past experience that I could likely just switch A to D pins and be good to go. Finding the source code for the Plastruder board was the hardest part of this task. I feel like I am missing something obvious here, but I spent hours reading wikis and blogs with no avail. After all that I was only able to find an older version, so I used that. I switched the firmware to use pin 7 and soldered my own filter and pull-up circuit floating in a pool of hot glue above the aux pin 7 socket. The last problem was to get the Plastruder to actually extrude. The idler wheel was not tight enough, and the ABS was stripping. My first solution was to over-tighten the idler wheel, unfortunately chipping it and breaking the entire thing. Luckily for me a lab partner quickly laser cut a new 6mm wide wheel, and after reconfiguring the Plastruder head I was able to make the new (faster, stronger) wheel fit. We also have a heated table. A few lab partners have seen it work, but I never have. I just connected the heater to a bench top power supply at about 2 amps and got a nice 107C on the table. Getting the raft to stick to the build platform is challenging, but adjusting the z axis by hand seems to do the trick. Finally, we’re printing parts on our MakerBot. Truthfully, the whole Plastruder is pretty janky, but MakerBot has just released a Mk5 Plastruder head and we’ve got one on the way. Stay tuned…

Cubelets are little robotic blocks that you can snap together to make bigger robots that drive around, do smart things, and act like they’re alive. With no programming involved, Cubelets are totally different from other robotic construction kits. Each little cube talks to its neighbors, and in the same way that flocks of birds can end up doing surprising things, robotic actions emerge from all of the interacting cubes. I’ve been working on this project since 2006 so I’m pretty excited to finally unveil the kit’s new name and logo. The kit used to be called roBlocks, but there was some trademark hassle. Moxie Sozo, a Boulder-based graphic design studio, did this fantastic logo design for us. Gorgeous web site coming soon. We’ll have kits for sale on www.modrobotics.com before the end of this year!

My friend Don Witte, the W in W.H.O., a construction kit toy company of the 1960s, designed several clever construction kits. In its day, his company was much in the same spirit as Modular Robotics is today. He wrote, “While adults are going to the moon, their children are playing with primitive wooden blocks, sticks, and nuts and bolts. Isn’t it time to provide our children with construction toys which fully utilize the advances in technology and the materials of the time?” We couldn’t agree more. The company produced working prototypes of four kits: Moduflex, Cylispheres, Zox, and MollyCools. They’re each different–Moduflex was perhaps the most technically sophisticated with gears and chains as well as a snap-together panel system, and it came in variations–a train kit, an architectural kit, and more. The prototypes were all made on an injection molding machine in Don’s dome in the hills west of Boulder. Sadly, they never came to market, but Don was kind enough to let me have his kits.

Eric and I have been jousting over who gets to use the only Digital Multi Meter (DMM) in our lab. To solve the issue Eric picked up a do it your self DMM Kit from SparkFun Electronics. This morning I had the pleasure of assembling it! As I opened the box, past memories of electronic kit building started to haunt me. How was I going to figure out which direction the capacitors went, or what resistor values went where? All my anxiety was washed away by the clearly labeled circuit board and the short, precise instruction manual. It was a breeze to assemble the kit, and once I found charged batteries, the new DMM booted its AVR microcontroller and functioned perfectly. With its simple, straight forward design and open source code, it’s going to be a challenge not to customize the firmware to make this DMM more my own. And now with the new laser cutter up and running at Modular Robotics, we should have a custom enclosure cut out in no time! For fun, I made a little time-lapse movie of the assembly.

We just moved Modular Robotics into a great new space in downtown Boulder, Colorado. If you’re local, come visit us at 2500 Pearl Street, right above Mike’s Camera. It’s no coincidence that our new building is in the shape of a cube. If you squint, you can see Mark through the window, and also the mad style of our old-doors-on-sawhorses work tables. And look – there’s UPS ready to bring our robots right to you.

I’m just now getting around to posting about the NSF SBIR Phase II Grantees meeting that I attended last month, in Baltimore.   Our SBIR grant requires that we attend this meeting each year.    The meeting is designed to help grantee businesses “share their technical and commercial achievements with the NSF program staff, potential investors and strategic partners, as well as having an opportunity to network with other small businesses for possible collaborations to grow their businesses.”   Lots of information to help techies make their good ideas become reality. Of course, with hundreds of companies in a wide range of technical areas, the meeting can be overwhelming.   For example, I went to a talk on “New Synthetic Approaches to Higher Performance, Lower Cost CO2/CH4 Gas Separation Membranes” — good stuff, but a little far from Modular Robotics’s core business.   Still, it was good to meet the other  SBIR II education grantees, which include our friends Alex Repenning (Agentsheets), Chris Hancock and Ricky Carter from Tertl Studios, and robotics company Road Narrows, Agile Mind (co-founded by Adele Goldberg), and many more.   I don’t have any pictures from the meeting (big hotel ballroom with lots of people), but  above you can see our dazzling entry for the poster session, where I also gave impromptu demos of our old prototype.

Hello! My name is Kelsey Metzler, and I’m a new design intern here at Modular Robotics. Over the last few weeks, I have had a lot of fun helping to set up the new Modular Robotics Studio Headquarters, learning all about the blocks, and contemplating how to build a 3D Printer (blog to follow soon!). Since I don’t get paid very much, I decided to take a play day. Today, I toyed around with Lego Mindstorms for the first time ever, and ended up learning a lot of really cool things! Lego Mindstorms is a fun kit that enables kids (or, adults…) to make their own robots. The kit, like any Lego kit, has many different types of building blocks, connector pieces, gears, axles, unique building blocks… anything you need to build a sweet robot. This kit also has Lego servo motors, a light sensor, an ultrasonic distance sensor, a touch sensor, and a sound sensor. All of this paired with the NXT, or the ‘brain’ of the robot, gives you one awesome kit. The software behind Lego Mindstorms is made by National Instruments, the producer of the major software LabVIEW. The Mindstorms software beautifully resembles LabVIEW, a graphic based programming language. The software is intuitive and easy to use, especially for someone with experience in LabVIEW. Today, I decided to see just what I could do with Lego Mindstorms. This is not only extremely fun, but is a great way to understand new mechanisms that might be used in future work. I started out by following some of the ‘Getting Started’ tasks that come with the Mindstorms software. These exercises are a great way to start getting to know Mindstorms. But, I wanted to do more! I started playing around with different ways of mounting sensors on the wheeled robot, logic for the robot involving case structures, and using many sensors at the same time. The most exciting, albeit fairly simple robot that I built today has been named Sam. He drives towards something, and as he approaches it, slows down until he hits it. After he hits it, he quickly races backwards, turns a little bit, and drives forward again. An interesting challenge in building this robot was to make a bumper that actually senses bumping! Just a simple small button will only detect straight-on hits. After messing around with different types of bumpers for a little while, I decided to just do a distance sensor: when the robot gets really close to something, it backs up. It was very fun to watch the robot drive around running into things on the floor! Then, I decided that I wanted to add clapping control. The goal was to have the robot pause for 2 seconds whenever I clap my hands. This didn’t turn out to be as easy as I had hoped! There are a few different ways I tried to do this: using a ‘switch’ block, using the ‘compare’ function, and using a ‘logic’ function. The thing that I found the most difficult about working with Mindstorms software is how very simple it is. I am used to working with LabVIEW, in which there are thousands of functional blocks to choose from. In Mindstorms software, there are less than 25. I discovered a ‘custom’ block option today, however… so it might be possible to make many more complex blocks to work with. In any event, I have not yet found a way to actually get the clapping control functional! At this point I just have a robot running around, charging into things and then backing up and doing it again. Wednesday entertainment: Sam.

We’re pleased to announce the award of a two-year $486,906 grant from the US National Science Foundation’s Small Business Innovative Research (SBIR Phase II) program.  The grant project is called “Learning About Complexity through Programming Modular Robots” and it’s for our work developing a system through which kids interact with our modular robot kits.  You can read the abstract at the NSF or take a look at our formal press release. One great thing about this grant is that it will let us speed up. Until now, we’ve been running Modular Robotics on a very tight budget with a very small team.  Our prototypes are still assembled in Eric’s garage.  The SBIR funding will allow us to hire three more people, move into a “real” studio, and make many more robots much more quickly. Another great thing is that it will let us slow down. Like any small business, we’ve been a little harried recently.  We’ve been trying to get our robot kit out the door as quickly as possible before we run out of money.  It’s expensive to make lots of tiny robots, so we’ve been making a lot of compromises in our rush to get something available.  Although we’re still going to have a first round of robot kits available this summer, the grant funding allows us to pay attention to the fine details of the design and make sure we’re releasing our robots thoughtfully and deliberately. Anyway, we’re thrilled.  Coming soon:  thousands and thousands of tiny robots.

Since we’re getting close to firing up the injection molder for our first run of commercial blocks, we’ve been thinking a lot about color. We use color to differentiate the different blocks by function, and we want the colors to both make sense and look cool when the blocks are assembled into a robot. In our research prototypes we made Action blocks white, Sense blocks black, and used rainbow colors for the rest. The rainbow just happened because of the material colors that were available for the Stratasys 3D printer we were using — it seemed a little too young, like how the color and scale of Duplo makes it obvious that it’s for little kids. And the white got dirty easily. For our first run, Sense blocks will still be black, but Action blocks will be transparent. The transparent cubes look great (they remind me of Capsela) and we’ll be posting some new photos shortly. And we’re settling on the color palette shown above for the Think and Utility blocks. It’s not a rainbow but the colors are easy to differentiate. It’s a little earthy, and since Passive blocks will be green, may even make a robot look a little bit natural.

One big influence on our Modular Robotics concept is the book, Vehicles, by Valentino Braitenberg. If you don’t already know this book, you’re in for a treat! In short and simple chapters, Braitenberg leads the reader through a series of thought-experiments in synthetic psychology. The ‘vehicles’ are creatures made of motors, sensors, and simple neuron-like logic gates. The first vehicles, for example, move toward or away from light. Gradually, as you connect the sensors, motors, and logic in more complex ways, the vehicles begin to seem to exhibit lifelike behaviors. How many Vehicles will we be able to make with our robotics construction kits?