Details: Those of you who have supported a Kickstarter project in the past may have recognized a project that showed up in yesterday's "Projects We Love" e-mail. "This Week in Kickstarter" featured PancakeBot, which I wrote about here in 2011 and spotlighted in advance of World Maker Faire 2012. For those of you just tuning in, this is a machine that can print pancakes with custom designs. The non-LEGO Kickstarter project is already well beyond the original funding goal, and will eventually be available for sale at $299 USD (you can still support the project on Kickstarter to get it at a lower price). Oddly, much of what's been written about the current Kickstarter project refers to 2013 as when the idea became the "working LEGO version" and 2014 as when the "First working prototype" was made. I was pretty impressed with the video from 2011, but perhaps a later LEGO version (that I can't seem to find with a quick search) was more reliable and is what they're now considering the "working" version.
There's been a considerable amount of hype around the Mindstorms line as a source of tomorrow's great inventions. This 'bot might be the first to actually go all the way from LEGO-based rapid prototyping to being a mass-produced product that people buy. If you can think of another one, let us know!
Details: To celebrate what would have been Alan Turing's 100th birthday, the Centrum Wiskunde & Informatica (CWI) in Amsterdam ran an exhibition of his work and influence through October 6th, 2012. One of the more abstract ideas, the Turing Machine, was brought to life through LEGO Mindstorms for this exhibit.
If you want to build your own (perhaps with a longer tape), there aren't building instructions (although you can probably figure much of it out from the photos and video), but the full source code is on GitHub.
Details:
This "milling machine" is an unusual approach to the 3D Printer concept - instead of using an additive process that slowly stacks up, this machine uses a subtractive process by taking a block of floral foam and trimming it down. That "trimming" is actually even more interesting - a drill (the only non-LEGO component here) digs in over and over again, and the final shape of the printed object is only visible after using a vacuum cleaner to suck away the thick layer of floral foam dust.
Details: Perhaps a demonstration of a concept isn't terribly exciting, but this dry-run of a CNC machine is captivating. The use of a large Power Functions motor to drive the "drill" component is a smart choice, but not as clever as the use of a separate speed computer so that the user can keep close tabs on it. Thanks to that, you can add a manual form of precision to the precision already offered by the NXT motors. The possibilities for combining this with actual power tools (or some capable LEGO equivalent) are endless.
Since I'm sure it'll come up in the comments - yes, we have technically featured a sort of CNC machine before (Pancakes, anyone?), but that one worked by maneuvering the head on multiple axes. This one actually moves the platform for the x and y dimensions.
Details: Try wrapping your head around the mechanism behind this model. Using only two motors and a simple program, this robot can turn in place, avoid obstacles, and balance itself by shifting its center of gravity. The builder is intentionally not making it too obvious how it works, but I think it's possible to reverse engineer some of it. The "feet" actually spin, so the axles going down to them must be geared to power that feature. The shifting of the center of gravity could be worked in by providing extra friction somewhere in the gear train - conveniently, this design combines that with the task of lifting each foot to take steps.
Some of the clever parts of this design don't actually involve gearing at all. Putting the weight of the motors low in the legs makes the walking motion much easier on the gear train. The combination of a touch sensor and an ultrasonic sensor handles obstacle avoidance in a way that should be easy to program - and since the ultrasonic sensor is mounted loosely, it sways from side to side to allow for more thorough detection of obstacles. This is a masterpiece of showing how to get a variety of features out of very few sensors and motors.
A brief note about this "of the day" blog: It just hasn't been possible to post daily lately. Among other things, last minute plans to be at all four days of BrickFair have eaten up time that would normally be spent posting. We'll get back on schedule after we come back with a full report from the event.
Details: This 3-axis (well, two axes plus a batter squirter) CNC prints pancake batter. The batter lands directly onto a griddle. Full details are on the website linked to above. I'll let you watch instead of spoiling the video for you.
Details: I've previously mentioned this builder's Egg Printer, but he's since made many more variations on the concept. This particular one prints a map of the world onto a round ball using three felt-tip pens.
Details: You may remember the first LEGO flexpicker robot built by today's builder a little over two years ago. While an excellent project, it wasn't the most realistic use of the technology - generally speaking, multiple delta robots are used together as part of an assembly line. Although that would be a mere quibble for most of us, it was reason enough for the builder to give it another go, applying various new techniques and algorithms to improve performance and reduce size compared to the original. A full description is at the site listed above.
Details: This may be the most useful LEGO robot we've seen yet. This machine can sort LEGO pieces by shape and weight. As you can see in the video, a handful of pieces are pushed out of a reservoir of LEGO elements, and a pair of conveyor belts move the parts from there to a digital scale. The digital scale is in view of a webcam, along with the piece on it. OpenCV is used along with some custom software and a custom database of parts to identify the pieces. From there, another mechanism puts it into one of eight cups based on what type of piece it is.
According to the blog posts describing this, this is just the first iteration. I can't wait to see where this project ends up.
Housekeeping note: in the interest of not letting things get out of hand, we will not be taking the time to make up the week we just accidentally skipped. We apologize for the inconvenience.
Details: Over the past few months, the builders of this battle tank has been posting information about it in drips and drabs on the NXTStep blog. Things seem to have hit a point where this is worth featuring - in this (nearly 10 minute) video clip, we can see it maneuvered around through a remote control, firing at targets (using a guide laser), and using the NXT motors to power a full drive system (with working suspension). We'll update this post as more details come out, but for now the video above will have to suffice.
Details: If you've seen the LEGO Education Renewable Energy Add-On Set, you've probably wondered if the windmill blades could be used to propel something instead. As it turns out, they can! They work wonderfully for steering blimps. The video here includes some footage from LEGOWORLD Copenhagen, where a video camera was attached to the blimp. For some meta fun, see if you can spot the photography rover driving around on the ground. I'm really hoping that somewhere, there's footage from that NXT robot of this NXT robot in action. I'm also trying to determine if I can make my own before the next LEGO convention I go to.
Details: Here's an interesting idea for making LEGO robots at events more interactive - giving people an NXT-enhanced helmet that can control a robot playing a soccer-style game. Third-party sensors (gyro and acceleration) are used to track head movements. Commands are derived from there and then sent (over bluetooth) to the robots on the field.
The most impressive part? This was all done in the graphical programming language that ships with the NXT - none of this was done with traditional text-based programming languages.
Details: Folding shirts takes time. Building and programming this robot to do it for you doesn't take that much time. The obvious next improvement is to make it grab the shirts itself so it doesn't need to be loaded with each shirt. This definitely speeds things up, though. The use of a cardboard box alongside standard NXT parts is pretty clever. In the interest of showing something you probably haven't seen before, the video above is of the second (faster) version of this machine.
Details: Now that the soccer/football table idea has been done successfully a few times, it was time to spruce up the concept. Here, we have one that includes ball handling and a computerized scorekeeper. The Power Functions WeDo system was used to give the laptop access to two motors and a pair of motion sensors. Fuller documentation's at the links above.
By the way - are posts with videos (like this one) still loading alright for everyone? YouTube seems to have changed how they handle embedding, and we want to make sure we're not losing anyone by using the newer embed code.
Details: It's a common problem - outdated media that's become difficult to use taking up space. Transferring the content from a pile of floppy discs to a larger modern hard drive can be time-consuming, but if you have enough of them it may take less time to create a robot to make it for you. This machine makes use of an NXT kit, an android phone, a Linux-based laptop, and some Python code. The external floppy drive probably simplified the automation process (compared to using a drive built in to the laptop), but the basic idea looks easy enough to apply. Now if only we could send in our floppies to be archived...
Details: There are some things that we all know are possible, but that few of us have actually gone all-in on. For example, you probably could build a passable Mindstorms NXT soccer-playing robot - or a score-keeping robot, or a simple mechanism that returns a ball that's fallen off a court. Here, it's pushed over the top - a custom-built soccer competition table is automated with a ball-return and score counter, and manned by three additional NXT-based robots - an overhead skycam and two competing soccer players.
It also helps that the soccer players are actually pretty good. Third-party sensors are used to allow them to navigate to their side of the field (through RFID) and to seek out a blinking ball (through IR).
Details: We've seen plenty of walkers before, but I haven't seen a fully steerable hexapod that uses only two motors before. One large Power Functions motor handles the walking motion, and a second motor articulates the body at two points to allow it to change directions. It's a surprisingly simple solution, but it works well. The other nice thing is that we now finally have a walker design that can be made with a LEGO robotics kit without using all of the motors in the kit.
Details: Here's a particularly strange LEGO electrical project for you. This one is far from purist, but the effect is interesting enough even if it does involve tinkering with valuable monorail track (you may think I'm kidding, but on BrickLink, a single piece of straight track can sell for over $20). If you're familiar with the model railroading hobby - or with LEGO's own 9V Train system - you know how a train can draw power from certain kinds of track that carry electricity. This is a much more efficient system than the battery-based type of trains LEGO current makes - you don't need to worry about replacing or recharging anything as long as you can hook up your speed regulator to a wall socket. Although the LEGO monorail system is fairly legendary, it too is limited by battery life. Until now! Apparently a bit of copper tape on the track and some hacking to make the motor draw power from brushes near the wheels is "all" it took!
More videos and photos are available - just follow the thread linked at the top.
Details: Naturally, pretty much everyone who has heard of Google's "Android" platform has been disappointed that it's not even remotely related to the android-style robots it has taken its name from. Recently, they've been working on making it easier for robotics hobbyists to use the Android platform with various popular robotics platforms - including the NXT. Since these are text heavy already (and you can browse through the links above to read about this at whatever level of depth you'd like), I'll leave it at that - start browsing at the links above for the news on the new App Inventor and Cellbots for Android.
Details: You may remember having seen this builder's difference engine some years back, but he now has another viral hit and fantastic mechanical computing model working its way across "teh intarwebs". This time he has taken on reproducing the Antikythera Mechanism, an ancient device that predicts eclipses. Discovered off the coast of Antikythera over a hundred years ago, the mechanism appears to have accurately calculated the locations of planets, the moon, and the sun - all based on a date input provided by a hand crank. For more information on the original machine, see the research website and this article in Nature.
Since the original mechanism was rather damaged when it was found, replicating the original gearing exactly wasn't really an option (nevermind the limitations in how many sizes of gears LEGO actually makes...) - so this machine is as close as possible to the original math, but features different actual gearing. More specifically, rather than very precise bronze gears, the exact ratios needed to get the calculations right are handled by differentials. Normally, when you see differentials used in a mechanical computer, they're being used to average two input speeds. That's not the case here. You'll need to look at the original webpage to fully understand exactly what was done here instead, and how that enabled the more advanced gear ratios necessary here. If tomorrow's LMOTD is late, it's probably because I'm still studying the details of this one.
. Since these are text heavy already (and you can browse through the links above to read about this at whatever level of depth you'd like), I'll leave it at that - start browsing at the links above for the news on the new App Inventor and Cellbots for Android. 
