Ng Beng Kiat is a talented guy who’s built many “micromouse” style robots. These tiny machines zip through mazes in disturbingly short amounts of time. His newest creation, Min5, is faster than the previous Min4A, which you can check out a really rad video of here. Watch the video all the way through - near the end Min4A does two optimized runs that are just insanely fast. What’s especially crazy is that somewhere, someone builds faster robots than this guy.
In a recent post, I covered Zonbu, a weird little computer that is really closer to a thin client than anything else. If that idea whets your appetite, you may be interested to know that there are plenty of other similar systems out there. Witness Koolu, Linutop, and fit PC. Not surprisingly, these machines are hardly household names, so no doubt there are other similar devices lurking deep in the bowels of the intarweb. As these little boxes become more powerful, it will be interesting to see if they gain widespread adoption.
I’m not big on picking up stories that all the other sites have covered to death, but this is just too cool. A 16 year old kid has built a bike made entirely of wood. To me, the most interesting part of the machine is the “ratcheting” mechanism that lets the rear wheel coast when you’re not pedaling. Though, I guess the chain was pretty tough to design.
Link - via Make
With the annual CES show kicking off, Wowwee is showing off their new products for 2008. The most interesting thing I noticed was the Rovio, which apparently includes NorthStar “GPS” - which I believe is actually NorthStar infrared localization, which was developed by Evolution Robotics. The development kit for this localization technology costs a cool $1700, while Wowwee’s robot will supposedly cost only $300. At that price, I would pick one up just to reverse engineer the NorthStar system.
So far as I know, the Rovio will be the first consumer robot to integrate NorthStar technology. Now if only Wowwee would build a cheap robot that uses VSLAM…
A really cool open source project that has been brewing for a while is OpenServo. The basic idea was to create a high performance replacement for the guts of standard hobby servos. The clunky RC communication protocol has been ditched for a much more convenient I2C interface, which allows a truckload of OpenServos to be controlled by one master device. That’s great, but the real achievement is cascaded PID control of position, speed, and current. On top of that, the developers have given OpenServo the ability to interpret motion profiles based on a few parameters. The hangup is that the hardware and software design so far is intended to be used with hobby servos only, which get position feedback from a cheesy potentiometer instead of a quadrature encoder. If quadrature encoder support was added (and I believe it is in the works), the hardware design should scale up really well for larger motors. The software is already to a point that would make it useful for a wide variety of applications other than small hobby servos. This should be a great project to follow.
It’s not very often that you run across someone who has crafted something unique and cool, but also genuinely useful. Tom Sharpless’s ScanCams fit the bill because they take impressive panoramic images using the guts of old scanners and photographic lenses. Especially interesting is his Mk4 machine. Granted, it may not produce images on the same level as the incredible Gigapan, but it is still an impressive achievement. It’s unclear if Mr. Sharpless has done any work within in the past few months, but we can only hope he will continue development of his awesome cameras.
There are as many techniques for precisely controlling a voltage as there are possible needs for such a technique. Here is a technique I wish I could take credit for, but you may not have seen before. The basic idea is kind of hackish: start with a normal adjustable voltage regulator (can be switching or linear, doesn’t matter) and inject a voltage onto the feedback node. The thing to keep in mind is that a regulator will do whatever it can (ie, raise or lower the output voltage) so that the voltage on the feedback node is always equal to a certain value - usually 1.25 volts. If we inject a voltage onto the feedback node, we can trick the regulator into raising or lowering its output. In reality, the idea isn’t as hackish as it sounds, because regulators are “basically” an op amp (with a high current output) and a voltage reference, which is exactly the key components that most fancy bench top power supplies are based on. The reasons why this technique is so appealing (to me at least):
Check out the attached Excel file. It will let you mess with resistor values and graph the output voltage. In the file, I have called the voltage we inject on the feedback node Vp. I’ve set up Vp to run from 0 to 5 volts with 10 bit resolution. This is only a brief intro to this idea and doesn’t represent a usable design. Maybe sometime in the future I can churn something out. Enjoy…
I have alot of projects that have most of the design work finished, but need finishing touches and the all important first build. These projects use the venerable ATmega168.
A balanced, bridged two channel amplifier. Idea came from DIYaudio. Actually this still has a fair bit of work left to do.
A super gnarly DAC + headphone amplifier. Has balanced outputs so it can be connected to the amp above. My attempt at “hi-fi.” I got a lot of inspiration and some schematic symbols from a project on DIYaudio.
A tiny robot/experiment board that has USB, 2.4Ghz wireless, dual H-bridges, and most pins brought out to headers. This is going to have to be manufactured at a pretty good board house because of the tight spacings on the CC2500 radio.
An LTC3401 boost converter.
An LTC1871 boost converter.
A “soft start” … this basically switches a power resistor in line with the primary of a transformer for a few milliseconds to limit in-rush current. The whole idea is that this circuit will let you pick a fuse that is appropriately sized for a large transformer since you won’t be having huge transients when the transformer is first plugged in. It’s a dangerous circuit because it works with live mains voltage, so I am kinda nervous about building it. Circuit came from DIYaudio, the layout is the only work I did.
RGB LED controller… after seeing Sylvain Bissonnette’s RGB LED controller, I just had to make my own. My version uses one LM3404 per color and has USB and IR interfaces.
In case you can’t tell, I like to layout PCBs. Keep checking back as I plan to complete these designs and publish ALL of the files.
You don’t have to look very hard to see that web based applications are becoming the new face of computing. While Google probably offers the largest and most comprehensive selection of web based apps, competitors like Zoho, Xdrive, and Facebook have all churned out impressive products that are competing very strongly with Google in their respective areas. That’s where a new site called AppJet comes in. It makes developing web based apps quicker and easier by allowing you to enter Javascript code right into your browser, store it on AppJet’s servers, and access it from a subdomain (myprogram.appjet.com for example). You can also view the source of any app hosted by AppJet. This gives you the ability to learn by example, improve on other’s code, etc. The significance of what AppJet is offering is pretty obvious. The question is, will any Google-crushing applications be built on their platform, or will it just be a collection of millions of useless “hello world” programs? The truth probably lies somewhere in between, but only time will tell for sure.
Virtual Cogs, similar to gumstix that came before them, are tiny ARM based “single board computers” with a family of proprietary add on modules. While not the first on the scene, Virtual Cogs’ front page boldly announces they are “open source hardware done right.” When most people think open source hardware, Arduino or Ethernut immediately come to mind. These two projects freely distribute their schematic and layout files in Eagle format for no charge. Virtual Cogs will provide you with schematics (in an undisclosed format) for a particular part after you have purchased it, but that’s it - no layout files. The concept of open source hardware is much newer than its software counterpart, and perhaps that accounts for the difference in opinions, but I still wonder what VC is thinking.
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