Ever since quitting his job as a successful hedge-fund analyst two years ago to dedicate himself full time to this labor of love, Khan has managed to win fans worldwide and goad skeptical educators.
His simply narrated, faceless home videos on everything from algebra to French history have been viewed half a billion times. Last year, a number of schools began “flipping” their classrooms, having students study Khan videos by night and do homework with teachers by day.
In the process, Khan has fueled the debate over tech’s growing influence on education while garnering the support of powerful friends.
“At 3,000 lessons online, Sal’s personal ability as a teacher is remarkable,” says Bill Gates, whose mention of Khan Academy at a conference in Aspen, Colo., in 2010 put the website on the map. “Bringing this kind of creativity and new assessment tools for teachers could make a profoundly positive difference in education.”
how do i send/control the L293DNE motor driver to power a SOLENOID or just a dc motor
This is a really good question, and quite a popular topic. The L293D or DNE, depending on the manufacturer, is a Quadruple Half H-Driver or H-Bridge IC that allows for the control of high current loads from a low current source. The advantage of this chip over just using a transistor or MOSFET is in the fact that you can control the polarity of your motor when used as a full H-Driver.
If you are looking to just control a solenoid, I would recommend using a transistor. Specifically one that can handle the relatively high current loads like a TIP120 or equiv. This transistor with a base resistor will be able to drive ~1A from just about any microcontroller. This can also be used to drive your motor and I actually ran a post earlier which gives a much more in depth overview.
Regarding your L293D, below is a circuit diagram that illustrates 3 possible configurations for driving a motor. The one the left shows the IC being used as a full H-Bridge. The pins are configured as follows:
Pin 1 (1/2 Enable) – Channel 1/2 enable HIGH = ON
Pin 2 (1A) – Channel 1 logic control
Pin 3 (1Y) – Motor Lead
Pin 4 – GND
Pin 5 – GND
Pin 6 (2Y) – Motor Lead
Pin 7 (2A) – Channel 2 logic control
Pin 8 (Vcc2) – Motor Power Supply
To turn CW, make 1A HIGH and 2A LOW. To turn CCW, make 1A LOW and 2A HIGH.
The diagram on the top and bottom right show how you can control your motor in one direction. The top right diagram shows the motor being controlled on the HIGH side and the bottom right diagram shows the motor begin controlled on the LOW side. The control scheme is essentially the same as above, though you will only be controlling one of the logic control lines.
I hope this has helped to answer you question and clarify the use of the L293D!
Don’t forget, everyone is invited to ask a question!
“Ask an Educator” questions are answered by Adam Kemp, a high school teacher who has been teaching courses in Energy Systems, Systems Engineering, Robotics and Prototyping since 2005.
Whoa! Researchers at Oxford have used radiocarbon dating to determine that a flute made of mammoth ivory is over 40,000 years old. More from the Oxford site:
In a paper published in the Journal of Human Evolution, the researchers describe the new dating results for animal bones, excavated in the same archaeological layers as the instruments and early art, at Geißenklösterle Cave in the Swabian Jura of southern Germany. The animal bones bear cuts and marks from human hunting and eating.
The new dates were obtained by Professor Tom Higham and his team at Oxford University, using an improved ultrafiltration method designed to remove contamination from the collagen preserved in the bones. The researchers show that the Aurignacian, a culture linked with early modern humans and dating to the Upper Paleolithic period, began at the site between 42,000 and 43,000 years ago.
The idea of humans making music 40+ millennia ago is inspiring and profound — making art is in our nature.
A large and precise 5-axis CNC machine is available for cutting positive and negative molds for large turbine blades. The robot or gantry, called HSM-Modal, comes from EEW Maschinenbau in Germany. It can mill 1:1 scale negative and positive molds for rotor blades that are 50 m and more, and in one single piece. The X-axis the on machine can span 151 metres. The machine also trims blades, and soon, it will lay glass-fiber mates into negative molds.
Neil Gaiman (1960-) is one of the best fiction writers in the world in my opinion. His work covers novels, short-stories, children’s books, comics, film, television – pretty much the whole pop-culture gamut.
This quote is taken from Gaiman’s commencement address at the University of the Arts in Philadelphia, which was all over the internet last week. In an absolutely beautiful and inspiring speech, Gaiman shares the best tips that he wished he knew when he was first starting his writing career. It’s required listening for anyone passionate about the arts and I’ve bookmarked it so I can watch it whenever I lose my direction. Seriously, if you haven’t seen it, stop what you’re doing and click here.
The mission of this website is to share our knowledge for building low-cost Conservation Drones to help conservation workers and researchers in developing countries do their jobs a lot more effectively and cost efficiently.
Of course, we recognize that there are highly sophisticated commercial UAV systems in the market and in use by the military, agricultural industry, and even the film industry. But most of them cost tens of thousands of dollars. Instead, we choose to adapt an autopilot system developed by an online community of hobbyists and developers (diydrones.com) to build our Conservation Drones.
Our emphasis is on low-cost. The challenge we give ourselves is to build drones that cost no more than a decent pair of field binoculars. These drones could also potentially be adapted for other environmental applications.
This project is partly supported by the National Geographic Society, The Orangutan Conservancy, Philadelphia Zoo, and the Denver Zoo.
The typewriter installation «On Journalism #2 Typewriter» writes generatively constructed stories about all journalist who have been killed worldwide between 1992 and today based on the existing data of their lives as well as their published work. The individual stories are connected through common fields of coverage, places, professions and many other aspects. Besides the text the typewriter creates also images e.g. flags which are heavier distorted the more journalists got killed in that particular country.
What are some quality resources for helping teachers prepare lesson plans with STEM material?
I am a Software Engineer that is helping my former high school develop their new STEM program, and would like to have some resources to help fine tune their classes, with both real world and class room material.
These Q/A posts have been very instrumental in the development of the program and I greatly appreciate your input.
This sounds like a great project and I am happy to hear you are helping out your former high school. It is really great when industry itself helps to develop STEM in education. Especially when the teachers are allowed to work with the individuals to help better their understanding about what is actually happening in the “real world.” This is one of the things that has always bothered me about being a teacher. I spend every school year preparing my students to enter higher education and later the work force ….. a place that I have really never been. Although I spend a great deal of time working in industry over my summers and researching the hell out of my curriculum, I will never fully understand what is actually happening in jobs I am prepping my students for. (Lack of this understanding is a real problem BTW…….I have actually heard of teachers LAMINATING their notes!)
This is where you come in.
You have been given an opportunity to help tailor an UP-TO-DATE STEM program for your school and are bringing knowledge to the table that textbooks can never supply. Kudos to you!
STEM programs can be a bit funny as Science and Math are required courses. And being required courses, they have required curriculum with standards testing to verify the students grasp. Updating the curriculum requires imaginative teachers that can both inject new and interesting topics into the classroom while hitting all of their benchmarks. In my opinion, the real opportunities in developing and bettering STEM in a school is through the Technology and Engineering. (Engineering is a bit funny too. What qualifies as an actual Engineering course in K-12 as apposed to a Technology course?)
Tech Ed is the needle in the rough. Although there are state and national standards for Tech Ed curriculum, there isn’t any national testing. Typically schools validate their Tech Ed programs through vocational and industry based certification tests. Talk about an open door. If you have an administration that is flexible and progressive enough, you can honestly propose just about anything intellectually stimulating that focuses on Engineering. How about a course in Aeronautics…….and not just Balsa Planes or Rockets or whatever…..but rather a course in Quad Copter flight dynamics? Take the state Aeronautics course code, meet the curriculum requirements, get it approved and BAM you have a course that will blow the students minds.
As for resources, there are tons. Here are just a few:
INTEL – Intel inspires the next generation of innovators with Science, Technology, Engineering and Mathematics (STEM) curriculum, competitions, and online resources to encourage students’ interest and participation.
NASA – NASA’s Education Materials Finder will help teachers locate resources that can be used in the classroom.
EPA – At EPA, we want to provide you a tool for talking about environmental issues. Or provide you a place to share environmental tips and ideas that you use every day.
PUMAS – PUMAS (poo’ • mas) — is a collection of brief examples showing how math and science topics taught in K-12 classes can be used in interesting settings, including every day life.
STEM Connect – STEM Connect is the captivating real-world STEM curriculum and career development resource from Discovery Education.
Museum of Science – “Engineering the Future” is intended to help today’s high school students understand the ways in which they will engineer the world of the future — whether or not they choose to pursue technical careers.
Best of luck and I hope I have helped with your question!
Don’t forget, everyone is invited to ask a question!
“Ask an Educator” questions are answered by Adam Kemp, a high school teacher who has been teaching courses in Energy Systems, Systems Engineering, Robotics and Prototyping since 2005.
Awesome author Gordon McComb is ready to add more sensors to his online Microcontroller KickStart series: basic, no-frills wiring diagrams and code examples for the BASIC Stamp 2, Propeller QuickStart, and Arduino Uno. Which one would you like Gordon to write next?
A comfortable wrist-worn leather bracer, that provides: time & date, compass heading, Exposure Value for photography, positional data, walking tracker (distance, time, average speed), galvanic skin response data, local temperature and humidity data, “alarm-clock” functions (alarm by time or countdown seconds alarm), and simple illumination / flashlight functionality.
The ISEB6 is powered by a small / lightweight Lithium-Polymer battery, running up to 48 hours usage on a single charge, and with a simple & fast on-board recharging system.
Add a typing interface to your project with this microcontroller-friendly miniature keyboard. We found the smallest PS/2+USB keyboard available, a mere 8.75″ x 4″ x 0.6″ (220mm x 103mm x 16mm)! It’s small but usable to make a great accompaniment to either a microcontroller project or a computer such as the Beagle Bone or Raspberry Pi. The keyboard supports either USB or PS/2 interface and will automatically adjust to whichever its plugged into (there’s an adapter included).
Comes with a full QWERTY keyboard, and has a num-lock number pad. Nearly all microcontrollers have existing PS/2 keyboard examples that would work fine with this keyboard. For Ardiuno users, we tried out PJRC’s PS2_Keyboard library with great success – just check the ‘simple text’ example for which pins you can connect to on your ‘duino (on an Uno we used digital pins 2 and 3). We suggest our PS/2 adapter cable to make the wiring easy. Start typing and you’ll see the data appear in the serial terminal!
Printable catalog (PDF)
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