BW Science Labs » Response

Robotics for Beginners: words of wisdom from a hobbyist who’s still alive

Brennon — Sun, 18 Oct 2009 03:41:00 +0000

I’ve been burned, electrocuted, and attacked by a rampaging robot* enough time to know the basic “do”s and “don’t”s of robotics.

I think we forgot to solder in the off switch…

I’m by no means an expert, but all the same I have a bit of advice for the beginner robotics hobbyist.

I recommend that if you go the book route you avoid most of the “Build a bot” titles. I got the most out of books and manuals on the microcontrollers I was using. The 3 picaxe manuals rock and are free (available at picaxe.co.uk) and I hear that there’s a great Arduino book out, but I haven’t had the chance to use any Arduinos yet (namely due to cost).

MAKE (makezine.com) has some great stuff on Arduinos in their blog and video series called “How-to Tuesdays”.

Here’s what I recommend: start with a cheap picaxe (don’t forget the motor driver chip!) and figure out how to get the wheels to move with the online manuals. Then, add a bumper switch and move on from there!

If you feel to afraid to even do that, then you should probobably go with the “have your hand held” route and follow a tutorial or buy a kit. If you do buy a kit, please, for the love of all that is good, do not buy a Lego NXT. They are drastically overpriced and won’t teach you nearly as much as others. I enjoyed my experience with VEX hardware, but their microcontroller ($50!) drove me absolutely crazy. You could, of course, get the brand-new ever-so-popular Vivus the Robot kit from the BW Science Labs Store.**

Footnotes:

*: called my brother
**: I really don’t want to toot my own horn, but the reason why I’m selling this kit is because I’ve found its good for beginners.

Practical Uses For The Geiger Counter

Brennon — Tue, 16 Sep 2008 18:56:00 +0000

“When it comes, will you please let your readers know what practical applications in everyday life the Geiger Counter will have? I have heard of it for years and thought it was good mainly for finding metals under the soil.”- Anonymous BW Science Labs Reader.

My Geiger Counter did arrive, but the only reason I was hesitant to immediately create a post was because the ebay seller failed to send the special headphones and the 6 dosimeter tubes as promised. The reason I can’t use any normal headphones is because the Geiger Counter I have is so old that it was a “phone” jack rather than a headphone jack. The seller has not responded to any of the emails I have sent to him requesting the items he forgot.

Furthermore, the six dosimeter tubes are still missing. Dosimeter tubes display how much radiation the wearer has accumulated over a period of time. Dosimeter tubes are checked periodically to see how much radiation they have been exposed to since its last charge. Dosimeters can also be in the form of badges that you see dentists an x-ray operators wear. The difference between a dosimeter and a Geiger Counter is a Geiger Counter tells you how much radiation your GM (Geiger-Muller) tube on the counter is picking up at one point in time. Dosimeters are better to use in a radiation lab while Geiger Counters are better for searching for radiation leaks, sources, etc.

An experiment I wanted to do with the dosimeters is see how much radiation an average person accumulates in one day going to school, work, etc. because as you read this, tiny radioactive particles are zipping through your body, however only in trace amounts. I wanted to see how much radiation there would be total. Unfortunately, I cannot do so without a dosimeter tube.

Metal detectors are typically used to locate metal (i.e. underground as the asker mentioned), but they fail to locate radioactive sources. That’s where the Geiger Counter comes in. Many houses are built on radioactive sources without knowing it. Also, something called Radon gas can inhabit enclosed areas, doing enormous long term damage to whoever lives in the house. By using a Geiger Counter you can check your home for radiation, which is pretty practical. After going through my home many times, I was “disappointed” to find nothing radioactive.

Many old watches are painted with radioactive materials to glow in the dark. Geiger Counters can pinpoint this radiation for you to clean up.

Thank you for your question, but please leave your first name later to make it easier to reply and reference.

Thanks.

The Mathematics, Science, and Future of Flight: Exploring Flight Theory

Brennon — Tue, 02 Sep 2008 02:15:00 +0000

“Can you write something about theory of flight and new navigation technology?”
This is what a BW Science Labs reader asked me a few days ago.
I am now very comfortable writing about flying as I have written many articles on the topic.
I first discovered the true basis of Flight Theory when I was 11. In Alaska, I asked a pilot to teach me to fly. It was a bolder statement than I first realized, but not at all impossible. It was then that I learned about weight (ok, when I was 11 I knew what weight was), lift, drag, and thrust.
Weight is the most obvious factor, the measure of the gravitational pull on an object, any fourth grader can tell you that. Because the plane stays on Earth during flight (excluding space ships, of course. “I’ll have to wait until I’m 16 to fly those,” I thought.) weight is a constant. It never fluctuates, though its Gs can of course. If you fly in an arc theWeightne point you will reach 0 Gs you will simulate zero gravity for a short period of time. NASA has a plane to train astronauts by taking them into a zero G environment for up to 40 seconds. NASA calls it the “Weightless Wonder” (cough*, cough* the Vomit Comet). Weight can be easily calculated using the basic equation w= mg, or Weight = Mass multiplied by the acceleration of gravity as a result of the pull between the Earth and the plane.
Lift is what keeps the plane up, and I find it more frustrating to explain. The Alaskan pilot Dan taught me that as you pull up, air particles are forced downward pushing the plane upward. This is in accordance with Newton’s third law that everything has “an equal [or proportionate] and opposite reaction”. I read another explanation years later, one a bit more confusing, but equally logical. The Bernoulli principle or effect as its called says that the shape of the wing splits the air into two parts. The air above the wing has less pressure than the air below it. Thus, the plane is pushed up not by air particles, but by a pressure difference. To this day there is still much debate over which explanation is correct.
Drag is the force that slows the plane down. Drag is also a fancy name for “air resistance” which a seventh grader can tell you about easily. The air in front of the plane resists the plane’s forward movement. Imagine running through a pit of floating bowling balls, the heavy spheres would get in your way, and you would have to push through them to continue. Though this metaphor is exaggerated quite a bit, the plane would feel similar resistance, just not on the same scale.
Finally we’re left with thrust, what moves the plane forward. Newton’s Second and Third Law are at work here. Propellers can pull the plane forward (or push if they’re on the back of the wings) by taking in air and pushing it backwards (once again, reverse the two for planes with propellers on the back).
In the title I promised to put a little something about the future of flight. In later posts, papers, and articles I will dive into depth of aerodynamics and how that will affect flight. By making plane airfoils and bodies more aerodynamic we can maximize efficiency in terms of speed and fuel consumption. I would like to see what future planes will look like. Unfortunately, I have to wait.

All data was checked for accuracy at:
http://web.mit.edu/16.00/www/aec/flight.html
and
http://www.livescience.com/technology/060828_how_planes_fly.html