RF finally alive !

I had bought two RF modules from Aerocomm (AC4790-1000) a few months ago and had designed a printed circuit board which allowed it to be powered from batteries and communicate with a serial communication port. However, as with every prototype, a few bugs arose that prevented me to actually communicate from one module to the other and back again, effectively removing all interest in the original planned activity.

After a few hard working hours I found the bugs and could finally work the modules the way they were intended to, as easily as the company claimed them to be (well it so happens that they are, I simply designed the PCBs in a hurry and missed obvious bugs, as they always appear to be afterwards).

Bug one was I had totally inverted the footprint of the DB-9 connector, solved by soldering it on the other side of the PCB, praising the lord that I didn't choose a surface mount connector this time.

Bug two was thinking RTS connects to CTS and vice versa. In fact, RTS goes to RTS and CTS to CTS, quite simply, but I thought the same logic that applied to RX and TX went the same for these flow control pins, but I turned out to be wrong.

The last bug is a big one.. the buck converter taking batteries to a bare 3.3 Volts was simply not powerful enough to bear the peak current of the (quite powerful) transmitters which is around 1.5 amps. After plugging a PC power supply on my boards, everything worked fine.

A new board with possibly a brand new buck circuit will have to be designed, but the concept wireless communication has been demonstrated to work just as initially planned.

One month without a post

It's been an entire month since I last posted on this blog, for quite simple a reason: I had no time. A thought I had while I was still having no time but I needed to take a break, so here is a post which hopefully will open the way to a series of others, more interesting.

As for why I was and still am very busy, I am just a week from graduation of a degree in Electrical Engineering, but as you may know from other posts I will begin a Master's degree in May, so I am not quite done just yet with university.

I will also be moving for that reason from my little native town Trois-Rivières to Montréal, where the École Polytechnique de Montréal is.

There's been a lot of paperwork to do for bursaries and time spent on finding the right apartment, and with all this I still had classes, worked 16 hours a week and got a couple (dozens) things done for my end of studies project, along with my usual volunteering.

I am glad this is nearly over and I will be able to move on to the next step (Master degree) from May 5th, where I am sure the combination of the flood of white papers and available time will renew my interest for research.

MIT OpenCourseWare

The MIT has been running some of their lectures on the web for a while now (OpenCourseWare), some of them might be of interest to you, in particular:

Electrical Engineering and Computer Science | Introduction to Algorithms

Physics 10 - Lecture 01: Atoms and Heat

In particular, Physics 10 has over 20 lectures on various subjects, almost never using mathematics, solely clever reasoning.

PicLens unfold browsing of images

PicLens is a plugin that allows for browsing pictures more efficiently and more naturally than ever. It uses media RSS feeds (Google Image, Deviant art, among others) and shows an infinite wall of pictures in 3d. Try it, you need it.

Brain-Machine Interface for Manipulating Robots Using Human

Yes, that's right, the guy plays rock paper scissors in a MRI and the machine reads his mind.

Honda Worldwide | May 24, 2006 "ATR and Honda Successfully Develop New Brain-Machine Interface Creating Technology for Manipulating Robots Using Human Brain Activity"

The Quantum Object

I have been reading a book (L'objet quantique - G.Lochak S.Diner D.Fargue - - Librairie Eyrolles), in French, about the quantum object. This kind of book is not an unusual reading to me, but this time I have been pleasantly surprised to see how the writers were not only very well educated in modern physics, but also able writers, giving a rare clarity to the usually destabilizing sides of quantum mechanics. The book keeps mathematics to a strict minimum, even avoiding the statement of Schrödinger's equation and instead using electronic repartition clouds as a visual aid to the solutions of the equation. Precious insights may be gained from this reading by quantum mechanics enthusiasts.

Science in retreat, Nature editorial says

According to Nature, it would seem Canada, after being in the top 10 as a research leader is slowly falling under the current government's policies. I hope the next government (soon ?) will understand the importance of science within today's globalization context. In this time when our industry suffers from a strong dollar, our expertise must not fall, it must raise.

Bursary for master degree

I had the confirmation today I will be awarded a bursary (see CGS M) for my master degree in electrical engineering I will begin in May or in September of this year. It will allow me to keep work outside my studies to a manageable minimum. I will work on subcutaneous wireless power and data transfer for Cortical Visual Prosthesis at École Polytechnique de Montréal.

Heli-OS advances, helicopter hovers using quaternions

Heli-OS, obviously for Helicopter Operating System, is a project I started a year ago with a friend of mine. The challenge is to render a radio-controlled helicopter entirely autonomous (no human input allowed for flight). Progress has been made recently as I grabbed latitude and longitude from a GPS in a C# application (not much of a feat, but I made a PCB to render the GPS USB), made a bridge between MatLAB/SimuLink and X-Plane (through UDP), and finally, made a successful hover of the helicopter (in simulation) using PID controllers on each axis (pitch, roll, yaw) and on altitude. Attitude is measured and controlled with quaternions, which allows me to define the error in the control loop as another quaternion, representing the rotation between current attitude and desired attitude.

Speech Recognition

Recently I have been fussing with speech recognition under Windows XP (I am not yet a Vista enthusiast [I tried it] and speech support does not ship with XP as it does with Vista). Being a programmer, I was more interested in using speech recognition within my applications than within Word or the operating system itself. I finally found a way to use System.Speech.Recognition (I am a .NET fan) with C# to distinguish between certain given terms. The engine is highly sensitive and often gives false positives, but is pretty deterministic and gets it right most of the time. Increased difference of pronunciation between expected words and the smaller their number, the better the recognizer will operate. Contextual dictionaries are the key to successful non annoying speech recognition.

Google Custom Search Engine

I have been spending some time on Google looking at a few peculiar services they provide and tumbled on this: Engineering Podcast Search Engine

In other words, Google allows you to create your own search engine, that is specify keywords added in background to your search and a list of websites to search within.

Learning Japanese

It may have shown either from my spelling, grammar and especially from my name that I am not an English native. I speak French as a mother language, and I can read some Spanish (I had 4 years of classes on it in high school). However these languages all use the Latin alphabet with some variations, French and Spanish being romance languages and English being a germanic language.

I decided to learn Japanese, a long and hard journey it seems. The japanese language is written using two distinct syllabaries (Hiragana and Katakana) and Kanjis (imported chineese caracters from the Han Dynasty (206 BC – 220 AD)). Until now I know the Hiragana syllabary and I am progressing with the Katananas. Both have 46 distinct symbols, mapping to syllables. Kanjis are much more of a long shot though with their 1945 official minimum symbols. According to a site, the actual upper limit to these is more around 50 000, while a working knowledge of them would be around a few thousands.

Monkey controls a (third) robotic arm

Scientists have interfaced a robotic arm to a BMI (brain-machine interface) implanted on a monkey. Results, if not a hoax, are pretty interesting to the very least. YouTube - Monkey controls a robotic arm

WiTricity

People at MIT have found an elegant match of the wireless concept and 175 years-old induction law. Read the story at: Goodbye wires… - MIT News Office

Welcome

The name of this blog, window on the world, is a simple reminder that one's vision on the world is very limited. Even though the ubiquitous Internet reduces far to close and long to short, the quality of the information seen daily is still very random. The goal of this blog is to present a selection of enlightenments encountered while I was surfing the web. If you enjoy science, chances are you will enjoy this blog.