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Howdy everyone!

It's been awhile since my last post. Things are still hectic around here. The Michael Jackson Tribute concert unfortunately fell through. I think there were some management issues with the production company, but that was actually a good thing for me. I was probably the only one smiling when they announced that we were cancelled from the show. With the extra time, I've been scrambling to put the finishing touches on the product designs and get the shop up. I'm pretty excited about it, but its been much, much, much more work than I ever expected. I've also been busting some ass to finish off all of my tax returns since the Japan deadline is March 15th. Overall, the schedule has been really ugly lately. 

On the plus side, I should be getting more active on blog posts soon because I'm going to need to write a lot of tutorials on how to use the boards that I'm designing. The shop will mostly focus on WSN developers since from my experience, we're an often ignored group, yet vital to  bringing wireless sensors to the world. I won't get into it too much here since there will be a separate post about it when the shop is ready to go live.

Just as a word of warning, I'm neither an RF expert nor pretend to be one. I spent most of my days in the university ditching classes, hanging out at coffee shops, and attending dance rehearsals. I spent the next decade and a half pretending to work at my various jobs. I'm the furthest thing you can get from an PhD'd RF engineer. But if you're willing to accept all that and are still willing to believe me, then read on:

I made a very interesting discovery recently while I was trying to improve the range of my 2.4 GHz wireless boards. I was getting limited range out of the on-board SMD antennas that I was using and was doing testing on multiple boards to see if it was due to the variance of the discrete RF components or if it was an inherent property of the system.

The funny thing was that in my sample of about five boards, one board constantly demonstrated a high received signal and transmitter output, almost twice that of the other boards. I was keeping detailed notes of the component values on all the boards so I copied the exact same component values on another board but couldn’t duplicate the results. The complete matching circuit was identical and I even replaced the radio and the balun to see if those were causing the discrepancy.

I spent about two days investigating this and trying to get to the bottom of why that one board was constantly outperforming the rest of them. I finally found the solution and it was staring at me in the face.

On all of my radio boards, I have two antenna options. One of them is for the onboard SMD antenna and the other is for the right angle SMA connector which can interface to external antennas. You can choose between the options by moving a capacitor to either the SMD antenna path or the SMA path. The board that was constantly outperforming the others had the capacitor in the SMA path rather than the SMD path. The strange thing was that there was no external antenna connected to the SMA.

When I was in the bay area a couple of months ago to visit my sister, she told me about a new series she was writing on Corporate Dropouts . Those are people that have left their jobs to pursue something more meaningful to themselves. Since I just so happened to be a corporate dropout, she interviewed me on why I decided to take that path and what motivated me to continue. She also included a picture of me on the front page from a couple years ago when I was a bit...heavier...thanks sis.

Anyways, if you're interested in checking it out, you can find it here. You might also want to check out her other articles on Corporate Dropouts because I think it's fascinating. People actually doing what they believed in...who woulda thunk it!

Link

I was just watching the PBS FrontLine documentary on the Digital Nation and it completely irritated me. Here were professors from MIT, one of the best technical institutions in the US, complaining about the students’ use of technology. I can’t even say that this is ironic, as much as it is just plain stupid.

The crux of the argument is that students these days are completely distracted because of the internet. They’re in the classroom, but rather than listening to the lecture, they’re googling things, reading articles, or probably chatting with their significant other. The professor is frustrated because he gave a simple exam that just tested on whether the students were paying attention in class and the students score poorly. The immediate thought that came into my head was why was the professor blaming the students rather than his teaching methods.

I teach classes at the Tokyo Hackerspace. My first class was a basic electronics class that was done with a lecture format and I took three hours to deliver everything I thought participants needed to know about electronics. It was enough information to give them a firm foundation and understand the basics of voltage, current, resistance, capacitance, and simple design patterns. That was a mistake, and the problem wasn’t the participants, it was with my assumption that they wanted to know the basics of electronics.

I finally realized that the problem was that I was telling them the basics so they could build on top of it. But without experiencing it for themselves, they would never understand why you need to limit the current of an LED or why you need to have bulk capacitors on a power supply. One of the reasons why the new MAKE: Electronics book is so great is because they encourage readers to break things as well as make them.

Anyways, I finally grasped the concept that people want to discover things for themselves. They want to understand why certain things are the way they are, rather than just be told it. They want to build things and customize them to make it their own and put their stamp on it. This is the proper way to teach people and has been for centuries, where the old master/apprentice relationships still existed.

This post is a slight departure from my normal posts which are usually about wireless. But since I'm technically part of the wireless sensor networking world, I figured a fun, little post about sensing might be appropriate.

I actually put this together about six months ago to show to the Tokyo Hackerspace back when we didn't have a space. We were meeting in restaurants and would show off our latest weird designs over there. It was really a horrible place with a lot of loud drunks and people shouting at each other. And that was just inside our booth :)

Anyways, I showed them that if you used capacitive touch sensors, you would actually be able to draw your own buttons and be able to sense touch events on them. Incidentally, if you tweak the sensitivity high enough, you can also sense touch events through insulators like wood and plastic which I always thought was kind of cool. Perhaps I'm going to play with that some other time.

 

First of all, I just want to apologize for the amount of time it took me to set up a Chibi project page. Those that know me know that things are really hectic right now so I'm not moving as fast as I really want to. However I put up a simple project page for now so that there can be a centralized place where files are stored. It's pretty bare bones but I'll be fleshing it out more and adding tutorials, more schematics, and links to stable software releases. For the software repository, I'll be checking it into the Chibi GitHub repository where people can also download the latest version of the software. I just need to figure out how to use Github. 

So temporarily, I'm putting the software on the project page until I can move it into the main repository. This release is pretty important. I think there was only one public release of Chibi, but since then, it's gotten a lot of testing and I've received a lot of feedback from people in the Tokyo Hackerspace, as well as early users of the software. The feedback was awesome because it spanned a large range of users, from beginners in my microcontroller classes to professional hardware and software engineers. They've discovered bugs, told me ways to organize things better, and also enhance the usability. So this release has a lot of critical bug fixes, some re-organization, and support for a new driver...the AT86RF212. Did I mention that this chip is quite sexy? I think it's going to be a popular one and I think Atmel seems to have done a great job with it.

As for the bug fixes, you can get a detailed list on the Project page.

Link

I'm being a little bit quiet on the blog recently too, due to the volume of activity going on right now. However keep an eye out because there's going to be a lot more schematics posted, tutorials added, and some interesting stuff in store.

In the meantime, gotta finish my Michael Jackson costume lighting...*sigh*...

I just posted the Chibi v1.1 schematics. Apologies for the lag on everything. Things are so busy right now that I'm just struggling to keep up. I also need to create a project page for Chibi to house all the source code, schematics, and everything else thats going on with the project. It seems Chibi is getting more popular than the Zigbee stuff I'm doing. Guess I can understand since its much simpler and still accomplishes what most people want, ie: wireless comms. I'm finding it extremely useful for all the testing I'm doing. Here's some pics of the schematics and the pdf is at the link below:

Chibi v1.1 PDF Link

 

Welcome back! It’s a new year and it looks to be busy in the world of WSN. Hope everyone had a good rest over the holidays because I think things are going to be exciting this year. I can already see that remote health monitoring is going to be a big topic this year. With all the talk and debate about the health care plan in the US, it looks like its going to throw the subject into the limelight, possibly similar to how the smart grid stimulus shine a big ol’ spotlight on energy monitoring.

As for me, I spent the holidays at home, barely even leaving the apartment. The quiet time was good because I could focus on a lot of things that needed to get done. I finally got the new Chibi v1.1 boards in and had a chance to test them out. These are the ones with the DC/DC boost converter that can output a constant 3.3V supply as a battery is draining. So far, they’ve worked wonderfully. They also have a AA battery holder and I’ve been using 2500 mAHr batteries to power them. Those things are impossible to drain, at least in a short amount of time. It was a huge difference compared to the unreleased v1.0 boards that used a coin cell with no boost circuit.

I also got a chance to do some simple range testing, although I couldn’t do open field tests since there’s a real lack of open fields in Tokyo. Instead, I used the hallway outside my apartment which extends approximately 40 meters. I was able to transmit and receive with no problems over the complete range and actually had sore legs from all the walking back and forth.
I just wanted to wish anyone that reads this a Merry Christmas, Happy Hanukkah, and a Happy New Year. Everyone is pretty much winding down for vacation season so please take a break, get some fresh air, get away from technology, and enjoy the holidays! Next year will probably be crazier than this one so it'll be good to take a breather :)
Now that I’ve finished teaching my first microcontroller class to Tokyo Hackerspace, I must say that it was quite an enlightening experience. To put it mildly, I was pretty nervous about teaching it. Microcontrollers are a complex topic that combines software skill, hardware skill, toolchains, and hardware platforms. It’s not really a class to teach for the faint of heart, and most schools take three to six months to teach the subject…to engineering majors. So trying to cram all of that into a four hour class and teach it to people of differing backgrounds gave me loads of anxiety.

I think the difficult part was trying to figure out where to start. The famous saying, “ a journey of a thousand miles…” was useless to me because I couldn’t even decide where to take my first step. I eventually decided that I wouldn’t cover anything. I wanted to run things as simply as possible and get people toggling LEDs, moving motors, and reading sensors quickly.

To say that I wouldn’t cover anything is being a bit overdramatic. I structured things into a series of labs and prepared detailed lab notes on handouts that discussed everything I wanted to say. The lab notes also contained step-by-step instructions on how to perform the lab. Rather than being an instructor, I wanted to try being more of a lab assistant and have the class be a guided tutorial. The results were very impressive.

I decided to blow off some steam today because it's been so busy trying to get the webshop up and decided to hang out in Akihabara. After I arrived, I realized I didn't have anything I really needed to do, but just so happened to have my digital camera with me. I often get asked to show people around Akihabara and why I like the place so much. Since I had some time on my hands, I decided to do a graphical tour of Akihabara so people might be able to see a small piece of it through my eyes. These are the really hardcore shops, most of which you won't see from the tourist pics most people post. Hope you enjoy them :)

So much attention has been paid to digital technology in the past couple decades that its easy to forget our electronic roots. However I’ve been seeing an interesting trend in the past few years that seems to be accelerating. Just like bellbottoms and hippy gear, it looks like analog electronics is starting to become fashionable again.

Analog is the bane of electrical engineering students and conjures up bad flashbacks of analyzing useless circuit diagrams composed of passive components in bizarre configurations and trying to remember equivalent circuits for different types of transistor signal analysis for me.  It’s even worse for non-electrical engineering students because analog is a mysterious form of black magic that only bearded old men understand. Incidentally, all of those flashbacks were eliminated after I discovered two magical tools: SPICE simulation and Matlab.

It’s no wonder that analog has taken a backseat over the past many years as breakthrough after breakthrough in digital technology kept inundating us, showering us with cheap hardware, free software, and boatloads of information. But a peculiar trend seems to be emerging with the increasing tech savvy of everyday users combined with the mountains of information that are now available at everyone’s fingertips. That, along with the recent popularity of DIY hardware, hardware hacking, circuit bending, electronic art installations, and environmental sensing, are starting to spur curiosity in how technology can fit into our everyday world. All of a sudden analog electronics is back in vogue again and it seems to be coming from a culmination of multiple factors.