“One of the concerns I have with my children’s public schooling is the lack of differentiation in the classroom. What is your stance on this topic and do you use it in yours?”
Thank you for the question Jan! This is indeed a very important topic.
For those of us who are unfamiliar with differentiation:
Differentiation in the classroom pertains to efforts made by a teacher to adapt their instruction to meet the individual, and often unique, needs of their students. This teaching method is based on the realization that not all children are the same and therefore require different teaching methods and accommodations to obtain the goals of the course.
As a Technology Education teacher, the principle of differentiation has been a part of my teaching philosophy since day one. In order to earn your teaching license, you are required to conduct multiple semesters of “student teaching.” During one of these experiences I shadowed a “master teacher” for a couple of weeks, then took over his class for the remainder of the quarter. As I observed my “master teacher’s” teaching methods, it was clear that there was one student who he outwardly did not like. This student routinely interrupted class, didn’t participate during group activities and would make a point of not completing any work. My “master teacher” responded to these actions with negative criticism that exposed the entire class to the conflict, rather then address the root of the problem on a one-to-one level.
The day that I took over my “master teacher’s” class, I was instructed to administer a test. I separated the desks, passed out the tests and began watching the students answer the questions. As expected, the troubled student pushed his test away and verbally made it quite clear to me that he had no intentions of completing any portion. I approached the student, lowered myself to his eye level and calmly asked “what’s the problem?” His response was quite eloquent: “I don’t need to do this ****. My grandfather was a farmer, my dad is a farmer and I am going to be a farmer, so this **** is just a waste of my time.”
Remember, everyone is different and it is a shame that many teachers believe a student needs an IEP or a 504 in order to accommodate for their individual needs. I responded to the student in a way that helped him to see the importance of the material and how it could be applied outside the classroom. All he needed was to know that I cared about what he had to say, and that my approach to teaching wasn’t just barfing out “important” information that I then expect my students to barf back and forget after the test.
I always seem to come back to this story as I think it addresses a systemic problem in our education system. We live in a system where “no child left behind” has graced us with curriculum and polices that attempt to squeeze every student through the same conformal mold. Not every student is the same, nor should they be. As teachers we should make every attempt to provide our students with meaningful experiences that will help to shape their lives in a positive way. By differentiating our curriculum to meet our students needs, we eliminate dull laminated curriculum that gets taught year after year and challenge ourselves to think of new ways to engage and inspire our students.
More information regarding differentiation in the classroom can be found here.
I hope this has helped to answer your question and I encourage everyone who has had a positive or negative experience with differentiation to speak up in the comments section! I would love to hear what you all have to say!
Don’t forget, everyone is invited to ask a question!
Rob brought along a few Raspberry Pi Revision 2 Boards to show off for the event. He also brought along two very exciting products that will hopefully come out in the near future. The first one was the Gertboard, which we are looking forward to immensely. This is the creation of Broadcom employee Gert Van Loo. It enables the Pi to run servos and motors and the sensing of voltages and currents. The Gertboard will be a kit that you have to fully assemble, which includes soldering lots of small components. The Gertboard will open up a wonderful world of robotics projects for the Raspberry Pi. The second product is actually a 5MP Camera that will attach to the Raspberry Pi via a pin connector. This camera is being designed by Raspberry Pi and will be offered at $25 when it is released. Rob mentioned they created it because it would be hard for the general public to obtain a cellphone camera that takes 5MP stills and shoots 1080p video for $25. Rob said that the Raspberry Pi Foundation has buying power when it comes to getting these cameras and after all most of them work for Broadcom, so it’s great they will be able to offer these to us at such a great price. Rob will be developing the drivers to run the camera as soon as he is off the hackspace tour which ends in Austin, TX.
Swallow Hill Community College in Leeds has conducted a pilot ICT lesson using a Raspberry Pi, in an attempt to find out how the device could be used in education.
The single-board computer, which was developed in the UK by the Raspberry Pi Foundation, has attracted much attention for the potential it could hold in teaching kids the basics of computer science. It’s the metaphorical “red pants” of the current campaign to reinvigorate the teaching of computing — so much so that Google recently mentioned it by name in a pledge to fund a rollout of these types of devices in schools, along with a push for more teachers that specialize in ICT.
Mike Powell, the technical development manager at electronics webshopelement14, which is selling the device, took children aged between 11 and 12 through the basics of building websites, using the Raspberry Pi as a web server. The objective was to demonstrate how open source applications can be used in teaching, and showcase the range available on the device.
“The Raspberry Pi is the ideal teaching aid to inspire a new generation of engineers and computer experts,”..
The Terminal Link is quite impressive, as it create a cool linux terminal embedded into the web browser:
-we can also copy/paste text into it
-we can move it around
-We can call more than 1
Very nice job! i think i will use it instead of my Putty client (As i’m working headless with my raspberry pi)
Installed the IDE on Saturday it took a while but everything worked as advertised. It makes learning less of a hassle especially if you are running a headless Pi. I’m slowly working through http://learnpythonthehardway.org/book/ and hope to be starting to program something meaningful for my project in a couple of weeks. I’ve found a couple of little annoyance and will report them through git. Great job Adafruit!
We have decided to release the new Parts Editor in two phases. The first phase, included in the latest release (0.7.9), is already easier to use and more powerful than the old Parts Editor, but you still have to do a lot of preliminary work using an SVG editor like Inkscape, Illustrator, or CorelDRAW. In the next phase we hope to eliminate much of the need to use these programs.
hello. i have a question. i have a 6v mini el inverter which has a built in switch and is powered by 2 coin cell batteries. This inverter will be powering 2 seperate small squares of el sheet. But I also need it to power 3 rows of 4 LED’s.
How would I integrate the LED’s and connect them to my El Inverter? is it possible?
Ahh, there is nothing better then a little hardware hackery. For this post, I am going to assume that you are an “ebay special” 6v 2xCR2032 EL Inverter.
After inspecting the image, it appears that the circuit uses a standard slide-type switch for applying power to the EL circuitry. Assuming that this circuit switches power at the switch, which would turn the 6V on and off to the circuit, is where you would connect the + side of your LED array. The schematic below illustrates a rough diagram of the potential circuit:
Now, about connecting those LEDs. You have two main options for configuring them, series and parallel. Alternatively you could be fancy and use a switching driver, instead we are going to focus on the basics.
For these solutions, I am going to use LEDs with a Vf (forward voltage) of 1.5V and a Vi (forward current) of 15mA. You will need to know the proper values of your LEDs, these just happen to be at or below most.
In order to supply the appropriate power to your LEDs, you will need to use a series resistor. This “dropping resistor” can be calculated with the following formula:
R = (Vs – Vl) / I
Vs = 6V
Vl = Vf = 1.5V
I = Vi = 0.015A
R = (6V – 1.5V) / 0.015A = 300Ohms
Now that we know the value of the dropping resistor for one LED, we need to determine it for an array. The first two options are configured in series and the second two are in parallel.
Option 1 is the simplest solution as it only requires 4 resistors. Hypothetically, they could be connected to the battery without a resistor as (1.5V * 4 = 6V). This solution can result in an uneven illumination of the LEDs and if one burns out, the rest of the series string goes with it. The benefit here is a low component count and a circuit that only consumes 60mA.
Option 2 breaks the string of 4 LEDs into 2 series strings. By increasing the number of series strings, the chances for one string burning out goes down and you have proper circuit protection with the presence of the 200Ohm resistors. The disadvantage lies with an overall circuit current going up to 120mA, which would result in a shorter battery life.
Option 3 is configured in parallel and every LED has an appropriate dropping resistor. This method ensures an even illumination of the LEDs and if one burns out, the others are not effected. The major disadvantage to this configuration is the current draw, which rings in at a whopping 180mA.
Option 4 is a derivative of option 3, where the parallel LEDs are broken into pairs with 1 dropping resistor on each pair. This method can yield unpredictable results if the forward voltages are not matched. The result can be an over-illumination of the LED that can cause permanent damage or total failure.
Each of these options illustrate a potential method for interfacing 12 LED’s with your inverter. Personally I would chose one of the first two options due to their low component count and lower current draws. You might want to experiment with all 4 just to witness their differences. Before you begin your hacking, make sure that you REMOVE THE BATTERIES and turn the switch on for a few seconds to ensure the caps have discharged through the EL sheet and not YOUR BODY!
I hope this has helped answer your question! Good luck with you circuit and have fun with your LEDs!
Don’t forget, everyone is invited to ask a question!
Though I’m a huge X-Files fan, I’ve never gone in for some of the more esoteric UFO theories. But one thing I do love is solving engineering problems, and the problems posed by a flying saucer-shaped aircraft are real humdingers. Boundary conditions of stability and structural integrity are imposed by designs with a specified physical envelope and performance goals. So I’m really digging this article from Wired about US Air Force Project 1794, in which the problem of how to build a flying saucer was actually explored. From Wired:
Officially, aliens have never existed but flying saucers very nearly did. The National Archives has recently published never-before-seen schematics and details of a 1950s military venture, called Project 1794, which aimed to build a supersonic flying saucer.
The newly declassified materials show the U.S. Air Force had a contract with a now-defunct Canadian company to build an aircraft unlike anything seen before. Project 1794 got as far as the initial rounds of product development and into prototype design. In a memo dating from 1956 the results from pre-prototype testing are summarized and reveal exactly what the developers had hoped to create.
The saucer was supposed to reach a top speed of “between Mach 3 and Mach 4, a ceiling of over 100,000 ft. and a maximum range with allowances of about 1,000 nautical miles,” according to the document.
Listed below is my school’s press release. I have begun using Raspberry Pi in the classroom (after buying some of your stuff). My 7th grade girls were very excited about these computers in a formal setting. They will hopefully begin using the computers in ways I have not even considered. I would love to share what we are doing with other teachers, home schooling families and clubs and learn from them as well.
Middle School girls’ engineering classes first in America to program using tiny computer
Charlotte, N.C. — The Raspberry Pi has jumped the Atlantic Ocean from its home in Great Britain to Charlotte Latin School for its debut in an American classroom, announced Headmaster Arch N. McIntosh, Jr.
The credit card-sized computer provides an open source operating system and features that give students the opportunity to learn physical computing and programming by allowing them to take apart and reassemble the $35 unit.
As he introduced the Raspberry Pi to his students today, engineering teacher Tom Dubick said, “It’s like a sandbox and you get to play and try new ideas. I am excited to see what you will do with the Raspberry Pi that hasn’t even been thought of yet.”
The engineering class will utilize the Raspberry Pi to learn programming in Scratch and Python and to build systems using sensors, motors, lights and microprocessors such as robotics solutions. Traditional productivity applications like word processing and web browsing also will be explored.
My question is, I want to read if a lamp in a 24 V alternating current circuit is on or off. I want to use an arduino, but I guess I have to do some kind of signal conditioning, any tips for breadbord testing?
Thank you! I am glad you like the posts!
Now, regarding the question. I have three methods you can employ to sense if your lamp is on or off, and each vary on how much hardware hacking you are looking to do. The first utilizes an opto-isolator to sense the presence of your AC voltage and convert it into a logic level (0 or 1) output that can be easily sensed by your Arduino. This is the most stable and easier to conceal method of the two. The second utilizes a relay, which activates when the lamp is turned on and is connected to the Arduino as you would a pushbutton. The third doesn’t actually interface with the lamp’s circuitry at all, rather relies on one of the Arduino’s ADCs and a photocell to sense a dramatic change in light intensity, indicating the lamp being turned on or off.
Sensing AC with an opto-isolator:
An opto-isolator or optocoupler is a electronic device that uses an LED and a phototransistor to electrically isolate two parts of a circuit. This comes in handy when interfacing microcontrollers with devices that produce a lot of electrical noise, or voltages that could be harmful. Digikey carries the HCPL-3700 which is, although a bit pricey, immediately capable of converting the presence of 5 – 240V AC/DC to a logic level output. In order to make a safe and stable circuit, I would recommend using series resistors for current protection on both the input and output as well as including the recommended 0.1uF filter. You can also complete the circuit using a cheaper isolator like the 4N25 and a few support components as the input is directly connected to the LED.
For more information, there is a nice overview and series of examples on W9XT’s HAM website.
There was a similar question to this on the Adafruit forums that might be of use as well.
Sensing AC with a relay:
A relay is an electro-mechanical device that physically switches its outputs based on the energized state of an electromagnetic coil. Relays typically have common(C), normally-closed (NC) and normally-open (NO) pins that refer to the state of connection relative to the state of the coil. If the relay is not powered, and your light is off, there will be an electrical connection between the C and NC pins. When the relay is powered, and your light is on, the electrical connection switches, connecting the C to the NO pin. These pins can then be connected to the Arduino in the same way you would connect a button. All you need to do is connect a pull-down resistor and an input to the C pin and connect the NO pin to VCC. When the power is supplied to the lamp, it will energize the relay’s coil and connect the NO pin to the C pin, thus changing the logic state from 0 to 1.
Sensing light with a photocell:
A photocell is a device that changes resistance in correlation to the quantity of light it is exposed to. As you are sensing the light from you lamp, I would recommend one used to sense frequencies in the visible light spectrum…..like these. The idea behind using a photocell for sensing the state of your lamp would be to continuously sense the ambient light level in the room. Then use software to implement a threshold that triggers when the light level jumps/drops. You should place the photocell as close to the lamp as possible in order to help eliminate false positives.
I’ve been working on a project called Visualight, an open source wifi connected lightbulb that visualizes data as colored light. It connects to weather, NYC MTA and social networks to displays alerts as colored light. Its also connects to the New York City sewers as part of DontFlushMe to alert people about sewer overflows, like today!
“These walls have a soul,” said Axelle Doué, a model who was once the muse to designers like Thierry Mugler and Claude Montana, sitting beside a makeshift runway here amid the battered old concrete and columns of a gallery in the Palais de Tokyo museum.
“But you know,” she said, “clothes do, too.”
It is true, as fashion historians would attest, that clothes tell a story. But what they can actually tell us, long after their owners are gone, is a matter for interpretation, which turns out to be something of a specialty of Ms. Doué.
We think electronics can have “souls” – it’s the code we put in them, our hopes and dreams for what a project can be. As we get ready to launch FLORA, we hope to tell the story of how electronics can be art.
Cody Wilson planned in the coming weeks to make and test a 3-D printed pistol. Now those plans have been put on hold as desktop-manufacturing company Stratasys pulled the lease on a printer rented out for Wiki Weapon, the internet project lead by Wilson and dedicated to sharing open-source blueprints for 3-D printed guns. Stratasys even sent a team to seize the printer from Wilson’s home.
“They came for it straight up,” Cody Wilson, director of Defense Distributed, the online collective that oversees the Wiki project, tells Danger Room. “I didn’t even have it out of the box.” Wilson, who is a second-year law student at the University of Texas at Austin, had leased the printer earlier in September after his group raised $20,000 online. As well as using the funds to build a pistol, the Wiki Weapon project aimed to eventually provide a platform for anyone to share 3-D weapons schematics online. Eventually, the group hoped, anyone could download the open source blueprints and build weapons at home.
At tonight’s traditional paella maker dinner at NYSCI in Queens, I spotted Jeri Ellsworth sporting some beautiful LED eyelashes (and necklace, and dress). Diana Eng was making magic with SMT LEDs on many people– I spotted MAKE editor Gareth Branwyn’s bald head covered in blue dots, and even Matt Richardson had an LED mustache. Ah, the fun that is Maker Faire… hope to see you there! I’ll be with the Dueling Mechanical Bulls by The Madagascar Institute (near the Diet Coke & Mentos stage).
The Open Hardware Summit is the annual conference organized by the Open Source Hardware Association and the world’s first comprehensive conference on open hardware, a venue to discuss and draw attention to the rapidly growing open source hardware movement. Speakers include world renowned leaders from industry, academia, and the DIY community. Talks cover a wide range of subjects from electronics and mechanics to related fields such as digital fabrication, fashion technology, self-quantification devices, and DIY bio. Discussions and panels focus on, but are not limited to, education, manufacturing, design, business, and law. As a microcosm of the Open Source Hardware community, the Summit provides a friendly forum for discussion in line with our policies and desire to be as inclusive as possible.
Hopefully this will be a bit easier of a retro-ware than the previous month’s! I’ve included photos of all three circuit boards that I have from the ware. Again, this is one for which I have no idea what it is from, but have been curious about since childhood.
The way we understand the world relies so much on our ability to measure it. Given that many measurements are based on the proportions of the human body its clear we measure stuff to find our place amongst it all and to connect with it in some way. By exploring the world at hand, from the basement to the backyard, I have found a resonance in things. An energy vibrates in that space between our perceptions of the world and the potential the mind senses for our interventions within the world. This energy is the source of all true art and science, it breeds those beloved “Ah Ha!” moments and it allows us to sense the extraordinary in the common.
For me, wonder is a state of mind somewhere between knowledge and uncertainty. It is the basis of my practice and results in images that are simultaneously familiar yet strange. Each piece begins as a question of visual possibilities and develops in tandem with the natural laws of the world. Serendipitously, this process often yields unexpected results measurable only through photographic processes. The human presence and artifacts of the process provide a clue to the creation of the photograph while adding to the mysterious nature of the image. My hope is that this work affirms that even within the well tested laws of science there are, and must always be, pathways to reinterpretation and discovery.
With the passing of IDEO co-founder Bill Moggridge, we have been reflecting on the ways he has influenced our lives and made the world a better place. Bill has had an enormous impact on the field of interaction design and professed the importance of making interactions delightful.
For IDEO Labs, we wanted to do a tribute to him in a very IDEO Labs kind of way. Perhaps one of the most iconic objects Bill designed was the GRiD Compass, the world’s first laptop computer. Bill’s design was the original clamshell design that all current laptops have descended from. We wondered if we could use a GRiD as a way to collect stories about Bill from around the office.
The result is this GRiD Laptop that has been modified to house a Galaxy Tab. It renders everything in orange and black similar to the original GRiD, boasts a working keyboard, and can be plugged in to charge at the base behind the original door that housed the ports.
We are using this laptop as a way to add content to billmoggridge.com which has been created to honor him by sharing our favorite moments, Moggridge-isms, photos, videos, songs, and more.
I hope this puts a smile on your face, just as Bill has done for so many others during his lifetime.
As per usual, I tried to document and share all the details of the build process for others to learn from. Click through for the full details of what went into this build…
With IPV6, it looks like I can have unique internet addresses for all my Internet of Things/Web of Things. How can I get my Arduino projects to use IPV6
Interesting question Mike! But first, for those of us who are not familiar with IPv6:
IPv6 or Internet Protocol version 6 is the most recent standard communications protocol for the internet. This version solves many of the protocol problems faced with IPv4 including support for an almost unlimited number of unique device addresses….2^128 or 340,282,366,920,938,463,463,374,607,431,768,211,456 devices. Phew. Considering that the World’s population is 6,973,738,433 (from Google) would mean that each person could have approximately 4.9 x 10^28 uniquely addressed, internet-connected devices. With numbers like this, its not hard to imagine a future where every electronic device is capable of interfacing with the internet, maybe even your coffee maker.
Now, about getting IPv6 running on your Arduino. There are already a few libraries that make this possible, and most rely on the Arduino Ethernet Shied:
The official Arduino Ethernet Shield is based on the WizNet 5100 chip, which implements the IPv4 protocol stack in silicon. As a consequence, the Arduino Ethernet Shield cannot be used to implement an IPv6 stack.
To implement an IPv6 stack, it is necessary to use a shield based on hardware that permits the management of IP and Ethernet layer functions. Shields based on the MicroChip ENC28J60 chip (such as those sold by Ekitszone and Nuelectronics) are suitable for the implementation of an IPv6 or dual IPv4/IPv6 stack. This approach requires the TCP state machine to be implemented in software and results in more complex arduino code.
I wrote an additional wrapper class with initialization methods, so the sketch files should be pretty simple. Included in the library you will find the following examples:
IPv6TelnetServer, where you can put/get the status of an attached LED and where you can get information about the free RAM bytes. IPv6WebServer, where you can get the current values of the analog input pins.
While sometimes quick and dirty works fine for footprints, if you ever have to deal with enclosures or particularly dense boards, you’ll soon find out that accurate footprints can make your life much easier.
There are some really nice, detailed and accurate footprints in the default Eagle libraries, but there aren’t a lot of resources out there on how to create them. This guide will hopefully serve that purpose, highlighting what works for me making connectors and similar types of footprints.
I finally got some time to put together a good overview/demo video of the Adafruit Learning System. If you have never checked out learn.adafruit.com before, or even if you have followed a few tutorials on it, you will hopefully learn some of the not-so-obvious features of the Adafruit Learning System in the video.
If you don’t mind a Minnesota accent, check out the video and let me know what you think. At the rate we are pushing out updates for the Adafruit Learning System, I have a feeling I will have an update to this video within a few weeks.
The Course Builder open source project is an experimental early step for us in the world of online education. It is a snapshot of an approach we found useful and an indication of our future direction. We hope to continue development along these lines, but we wanted to make this limited code base available now, to see what early adopters will do with it, and to explore the future of learning technology. We will be hosting a community building event in the upcoming months to help more people get started using this software. edX shares in the open source vision for online learning platforms, and Google and the edX team are in discussions about open standards and technology sharing for course platforms.
This website is here to guide you through the process of developing very basic operating systems on the Raspberry Pi! This website is aimed at people aged 16 and upwards, although younger readers may still find some of it accessible, particularly with assistance. More lessons may be added to this course in time.
This course takes you through the basics of operating systems development in assembly code. I have tried not to assume any prior knowledge of operating systems development or assembly code. It may be helpful to have some programming experience, but the course should be accessible without. This course is divided into a series of ‘lessons’ designed to be taken in order as below. Each ‘lesson’ includes some theory, and also a practical exercise, complete with a full answer.
Rather than leading the reader through the full details of creating an Operating System, these tutorials focus on achieving a few common tasks separately. Hopefully, by the end, the reader should know enough about Operating Systems that they could try to put together everything they’ve learned and make one. Although the lessons are generally focused on creating very specific things, there is plenty of room to play with what you learn. Perhaps, after reading the lesson on functions, you imagine a better style of assembly code. Perhaps after the lessons on graphics you imagine a 3D operating system. Since this is an Operating Systems course, you will have the power to design things how you like. If you have an idea, try it! Computer Science is still a young subject, and so there is plenty left to discover!
Want a FREE Raspberry Pi? For limited time and while supplies last – Adafruit is including a FREE Raspberry Pi in all orders over $350 (not including shipping). This offer is for online customers only, not distributors/resellers/hackerspaces.
Hope you like this one. It’s a robot controlled by Arduino, Adafruit ethernet shield and an Android client. (There’s source for an XBee/Adafruit motor contoller version, too, but no pictures or video of that.) Link has everything you could want – schematic, documentation, source code links, video and a picture of a bunch of geeks. Oh… okay… everything you could want and more, then.
Ben uses an electron microscope in an attempt to take a look at a 555 while it’s operating. He writes:
I used my DIY scanning electron microscope to view a 555 timer circuit while it was powered. The circuit is a simple oscillator with a very long time constant to make the changes easy to see. My plan was to view the silicon die itself, and hopefully discern changes in its internal circuitry as the oscillations occurred. As it turns out, I was only able to “see” the charge of the electrical wires going to the chip socket. There is likely a clear oxide layer that covers the silicon die, and needs to be removed with hydrofluoric acid in order to use the SEM to inspect the die itself while powered.
While he wasn’t successful this first time out, it was still pretty cool to see how he went about it, and learning the hazards of this kind of work. I look forward to seeing his next attempt!
▪ P2D and P3D have been replaced with variants of the OpenGL renderer. We’ve removed the software-based (but speedy for some circumstances) versions of P2D and P3D. We feel that OpenGL rendering is probably the future for most Processing work, so we’re focusing our efforts there. The change will cause some sketches to actually run slower, but the bottom line is that we simply don’t have anyone to help maintain all of this extra code. We hope to sort out the performance problems over time—if you see something weird, please report a bug.
▪ OpenGL 2 – a new version of the OpenGL library has been implemented, and the old one has been removed. The new library is based on Andres Colubri’s Android work (and his experiences developing the GLGraphics library). All the great things from Android have now been back-ported to the desktop version of Processing, so we have a super fast OpenGL library.
▪ OpenGL is now part of core – the OpenGL library is now built into the core, no need to include it as a separate library. This simplifies things (enormously), and brings better parity with other platforms like Android. This makes exported applications larger, but the benefits are worth it.
▪ Video – we’ve removed the QuickTime for Java video library and are using a modified version of Andres Colubri’s GSVideo library instead. On Linux, you’ll need to install gstreamer to use the new library. On Windows and Mac OS X, you should not need to install it, however we’re working out a few kinks in the whole process.
▪ Movie Maker – the MovieMaker class has been removed, because it was specific to QuickTime for Java. In its place there is now a Movie Maker item under the Tools menu, that helps you convert a file of frames into a video file. There isn’t a good library-based method to make this work, so it’ll probably stay a Tool rather than be re-incorporated into the video library.
▪ A new class called XML replaces the old XMLElement. With the change, you can call loadXML(“blah.xml”) from inside PApplet to read XML data. The rest of the API is the same as it was for XMLElement, except that getXxxxAttribute() is now just getXxxx(), for instance getIntAttribute() is just getInt() (to be more like the rest of the Processing API). Also added XML.parse(String) which returns an XML object from a String of XML data. Whitespace is preserved more consistently with the new implementation, which might require some changes to your code.
I’m basically married to Eagle until the end of days, simply because I’m so hopelessly used to it that it would take a pretty darn amazing package at a pretty darn amazing price to convince me to change. That said … there are some things that annoy me (though that’s true of any complex SW package). One of my biggest pet peaves is how hard it can be to find teeny tiny little unrouted airwires. Is Eagle taunting you with 1 remaining airwire and zoom as you might you can’t find it? I used to turn every layer off except 19, but that’s annoying since I sometimes don’t remember what to turn back on. While Eagle SHOULD have a feature to highlight these airwires … I found a better solution tonight searching for a mystery wire. Zoom back … WAAAaaay back … until your board is teeny tiny. Then select the Route tool and click just about anywhere on your PCB. This should grab the airware, and you can at least get an idea of where it is. Glamourous? Nope. Functional? Yes!
Today I finished writing the first part of my current project which involves connecting your Thermal Printer to a Raspberry Pi. For this I have written a Qt Class for communicating with the raspberry pi. I thought as you offer both items for sale your customers may like my class (which was inspired by your arduino class).
My next step (almost done!) is to write a Qt app (based on QT WebKit Browser) that can make snapshots of web pages, save them as a image and print them on the printer. With that it is possible to fetch news, images and almost everything and have it printed!
Hope you like my idea and maybe you like to write some lines about it on your blog. I will try to write some documentations and publish it on my webpage (tobiscorner.floery.net) ones I find the time.
I work at the moment with Arduino boards in my projects, but I don’t know if for other ones an Arduino Uno might be unsufficient (complex robots, computer vision, etc.). How can we now in advance if our microchip or board of choice will be sufficient? Could we get some advice and directions of chosing the perfect board for our project, and to how do the jump between Arduino and, say, ARM chips?
This is a really great question and I am sure is one that most of us will end up asking. What determines the “perfect board” can be pretty illusive, and given that Digikey lists almost 34,000 microcontroller variations, choosing the right one is not an easy task. As Arduino is pretty much limited to the ATTiny45/85, ATmega8, ATmega168, ATmega328, ATmega32u4, ATmega1280, and ATmega2560 there might be occasions where none will fit the bill……although I personally have not hit this wall.
When I begin the design process for a new project, I create a list of all of the features I would like the project to have, then attach the necessary I/O and pin requirements to each feature and generate a pseudo-schematic. As I am most familiar with Arduino, I look at the available chips and see which one most closely fits the bill. I.E. If there are just a few more I/O requirements then say the 328 can facilitate, I will either consider adding a MUX to bridge the gap or move to another Arduino compatible chip with more I/O.
Now, if you happen to be working on a project that is going to the more of a resource hog, moving to something like an ARM might be in your best interest. This tends to be the case when you move more in the direction of human interfacing, image processing, embedded OS’s, etc.
I have found a few articles that should assist in further answering the question:
It used to be that the number of different microcontroller chips available to the hobbyist was pretty limited. You got to use whatever you could manage to buy from the mail-order chip dealer, and that narrowed down the choice to a small number of chips.
Choosing a PIC according to your needs is sometimes a headache. There are people of course that hate headaches and therefore they use just 2-3 types of PICs and that’s all. That is a solution of course, absolutely inefficient though.
When choosing a microcontroller there are many options, so which platform should you choose? There is little independent information available to help engineers decide which platform might best suit their needs and most designers tend to stick with the brand with which they are familiar.
I am hoping to get [a] Maker group started and then grow it to the point where I can have [existing] equipment transferred to my name (as I am a civil servant) and eventually pull together [a] FabLab to be used by our local Maker community and STEM outreach.
To get the momentum moving, I was going to setup some meetings of the club to work through the Adafruit Academy requirements. Do you guys have any suggestions on setting this up? How does one become the appropriate instructor for the different topics? Any advice you can provide would be extremely helpful. I’ll, of course, get some of the badges too!
Part 1: Becoming the Instructor: (I will talk about setting up the Makerspace in a future post )
You have discovered one of the biggest hurdles any new (or seasoned for that matter) teacher faces when they are tasked with teaching new material. Here are a couple of approaches I have used in the past that have worked for me.
Approach #1: Always be two classes ahead of your students
The easiest approach is to compile your curriculum, materials and tools for the given topic and set up a rough timeline with benchmarks you anticipate the club/class to meet. By doing this you give yourself the opportunity to pre-learn the material prior to delivering it to the students. (This can be very challenging the first time around, as each class you teach often runs at a different pace.) This also helps to remove the initial burden of learning all of the material at once and gives your students a better experience than if you were scrambling through the entire lab.
Approach #2: Learn with your students
This approach is a little less predictable than #1. The idea behind this approach is to begin the topic by having a dialog with your students that discusses your expectations and that you are unfamiliar with the topic as well. You let them know that this lab is going to be learning process for the both of you and requires them to act with a level of maturity and responsibility greater than what is usually expected. You need to be careful though, especially with younger students, that the class doesn’t see this as an opportunity take advantage of the situation and breeze through the project. The flip side to this is that the method can actually boost their respect for you and your ability to instruct. By putting yourself on their level of experience, you are giving them a boost in responsibility that can make the lesson more meaningful and fun.
Approach #3: Make your students the teacher
This approach can be a lot of fun. I start by coming “clean” to the class by letting them know that I am as new to the topic as they are (just as in Approach #2). Instead of telling them that you will be moving through the lab together, you break the lab down into individual components and assign them to teams of students. The students get a class period or two to research, investigate and prepare an applicable lesson, then teach the class what they have learned. A good example of this is would be if you are working on a construction project, say building a Bird House. The Bird House project requires a fair amount of design, tools, and construction procedures in order to complete. You could break the lab into the following parts:
Surface preparation and Painting
Bird Observing and Identification
Food Consumption and other fun Statistical Analysis
The goal is not to necessarily teach each step of the Bird House project, but rather to teach the skills required to do so. The class then reconvenes and you proceed through the lab with your newly learned skills.
All three of these methods ultimately make you a legitimate instructor for that task. The first time though is always going to be a bit bumpy, but the more times you do it, the easier it will get and the more you can tweak to lab to add more content and more fun.
I hope this has helped to answer your question and best of luck setting up your Makerspace!
Don’t forget, everyone is invited to ask a question!
Adafruit do wonderful work. Giving back to the community is always appreciated and I only hope I can live up to the standard they are setting.
As a for instance, Adafruit put out a “zencart day” blog post where they talk about improvements they’ve made to their default install and offer it up to anyone else. What a time saver!
… except it doesn’t work out of the box. The plugin didn’t understand that I had a database prefix. It couldn’t load product images in the appropriate places or display “no image found” when needed. It wanted a Google CDN key and (as far as I can tell) Google doesn’t even offer CDN keys any more. The documentation said “remove these three sections if you aren’t using this other plugin” and it failed to mention there were another four sections that had to be removed. It isn’t nice to bite the hand that feeds you, so rather than complain to Adafruit I’m publishing my fixes here, just as they would have done.
Here’s a handy guild on how to build your own DIY Resistor Substitution Decade Box. I had seen several people online building their own, but instructions weren’t very clear. Hopefully these 50 or so pictures will help. First step – hop onto ebay, and pick up some switches. You can find them by searching for “decimal thumbwheel switch” – I think I only paid $5 for 10 of them including shipping (from china). Order up some extras – they can be used for all sorts of things – and a fun part to keep around.
Well, it’s that time again and our wicked summer is coming to an end. But don’t fret, we have a list of super cool gadgets for all you aspiring engineers that will keep your spirits high and your slide rules slidin’.
Apps for engineering: Just when you thought your smartphone couldn’t get more useful.
Mechanical Engineer, part of MultiEducator’s “Formulator” Line, is the perfect tool for any Mechanical Engineer or engineering student. Available for both iPad and iPhone/iPod Touch, our Mechnical Engineer app contains over 300 important mechanical engineering formulas, there are over 300 additional conversion formulas in the program as well as 70 area formulas. Major areas covered in the program now include: Actuators Bearings, Belts, Boiler, Brakes, Clutches, Elevators, Gears,Fluid Power, Heat Transfer,Internal Combustion, Kinetic Energy, Metalworking, Plates, Plumbs, Power Plants, Refrigeration,Shafts Springs and Vehicle Drive.
Tools for engineering: The following are tools that just about everyone should have in their backpack….or as their backpack.
Make your own iPod/iPhone/GPS/etc… battery-pack and recharger!
This project includes all the electronic parts necessary to build your own MintyBoost: a small & simple (but very powerful) USB charger for your iPod (or other mp3 player), camera, cell phone, and any other gadget you can plug into a USB port to charge. If you have a Nintendo DS/GBA or a PSP you can buy charger cables from us, too.
You need to charge your cell phone, iPad or Laptop and you don’t have a power outlet or even your charging cable with you … what can you do ? SOLARBAK is a cool, stylish and durable backpack with a detachable solar panel on it that will charge your devices from the SUN !!! SOLARBAK has a powerful new technology solar panel that charges a lithium-ion battery by using sunlight and even indoor light. The battery that comes with SOLARBAK will charge a dead cell phone very quickly as well as tablets, laptops and any portable electronic chargeable devices. SOLARBAK keeps you from being in a situation when you are powerless. Great for kids at school, music festivals, camping, hiking, biking, all kinds of travel as well as many other lifestyle activities. The 2 liter water bladder has a hose that reaches your mouth that can be used to hydrate you at events. SOLARBAK is made and guaranteed by VisionBay in Atlanta, Ga. … SOLARBAK … take YOUR POWER with you. Lithium-ion battery included.
This cute pocket oscilloscope is a perfect companion to your tool box. For beginners, its a good starter scope – it is not as complicated as a benchtop scope so its easy to use. For advanced EE’s, its useful as a scope-on-the-go, for field-debugging, when you don’t want to drag your scope over, or when a floating-ground is needed (it will naturally do ‘differential’ measurements as long as its not plugged into a computer USB port). It’s not a terribly fast scope, best used for signals up to 100KHz, and it is only a single channel, but we still find uses for it all the time, especially with analog projects!
Portage for your Projects! Lady Ada’s Bento Box is a crush-proof, drop-proof & water-proof prototyping kit that combines the ultra-rugged Otterbox 3000 with a storage tin and half-size (400-point) breadboard. In the middle is a spot for attaching an Arduino UNO (or any other PCB that has the same shape and mounting holes). There’s plenty of clearance for wires (even ones with plastic bits on the end such as our premium jumper wires or wire bundles) and parts on the breadboard, and the box is so sturdy you never have to worry about any delicate parts inside getting damaged. Toss it in your backpack, suitcase, duffel bag and you can be sure to work on it when you get to school, work or home.
Interfacing a new microchip can be a hassle. Breadboarding a circuit, writing code, hauling out the programmer, or maybe even prototyping a PCB. We never seem to get it right on the first try.
The ‘Bus Pirate’ is a universal bus interface that talks to most chips from a PC serial terminal, eliminating a ton of early prototyping effort when working with new or unknown chips. Many serial protocols are supported at 0-5.5volts, more can be added.
21st Century note taking: Below are some cutting edge note-taking (or not-note-taking) devices. I happen to be quite fond of my LiveScribe pen, as it has quickly taken the place of my tablet-pc and quad ruled notebooks.
Nexus 7 is a no compromise Android tablet that’s designed to go wherever you go. With a stunning 7” display, powerful quad-core processor and up to 8 hours of battery life during active use, Nexus 7 was built to bring you the best of Google in a slim, portable package that fits perfectly in your hand.
The Boogie Board Rip™ LCD Writing Tablet combines an exceptional, paper-like writing experience with the ability to record your written and drawn images and save them as files. Then connect to a computer and transfer files for editing, organizing, archiving and/or sharing!
Take the stress out of tests and meetings with an Echo™ smartpen from Livescribe. Record everything you hear, say and write, while linking your audio recordings to your notes. Quickly replay audio from your Livescribe paper, a computer, or a mobile device – all with a simple tap on your handwritten notes. It’s never been easier to take notes and stay organized.
The best notebook on earth, The Maker’s Notebook. From the creators of Make Magazine comes the Maker’s Notebook. Put your own ideas, diagrams, calculations & notes down in these 150 pages of engineering graph paper. We’ve also included 20 bonus pages of reference material, from useful stuff like electronics symbols, resistor codes, weights and measures, basic conversions and more, to really useful stuff like the amount of caffeine in different caffeinated beverages and how to say “Hello, World!” in various computer languages. The covers of this hardcover book are printed in cyan “Maker” blue with a white grid debossed front and back. Grab one today!
I hope everyone has had a great summer and good luck with this upcoming school year!
I’m not sure how this fits into the usual flow of things with EE Bookshelf, but given all the interest in the Raspberry Pi, I figured there are probably a lot of people out there for whom this might be their first foray in Linux. While there are a lot of good books and resources out there for Linux, it can be tough to wrap your head around which commands are available from the console, etc. The GNU Coreutils documentation does a decent job of showing what should be included in any distribution, and will hopefully help people get a bit more familiar with the command line. There’s also a PDF version for offline browsing.
If you’re just looking for a concise cheatsheet, there’s lots out there, but this one from FOSSWire should get you started pretty quickly.
Curiosity is the biggest, baddest, laser-wielding, plutonium-powered, robot-rover ever sent to Mars. On Sunday, August 5, 2012 it survived a dangerous landing that secured Mars exploration hopes for a decade. It will help answer the question of whether or not we are alone in the universe. Why not print this fearless hero for your desk?
Can 3.3VDC , 5VDC and 9VDC share a common ground. As in on a breadboard top row is 3.3VDC the next 5VDC then drop down to 3rd row for 9VDC and the bottom row be the common ground. This would be great with the large Adafruit breadboard with the 4 terminals. I would also like to place a diode in the 2nd to 5th holes in each column to prevent fly-back is that a good idea?
Great question and the short answer is YES! In order for your design to maintain a completed circuit, it is necessary for the powered devices to share a common ground. Lets say you have a GPS, a Boarduino, and a Solenoid in your circuit prototyping some sort of crazy Portal Turret. Each one of these devices require different voltage levels, while all communicating with the Arduino. In order for this communication to take place, each device will need to share a common ground in addition to some level-shifting circuitry. This level-shifting circuity allows for devices operating at different voltage levels to communicate. Typically a 3.3V device can talk to a 5V device without any problem. Although when a 5V device tries to talk to a 3.3V device, it needs to communicate through a buffer that shifts the HIGH/LOW levels into a range that doesn’t damage the 3.3V devices circuitry. **Below is a representative schematic. You will need to choose appropriate regulators/supplies to meet the requirements of your components…especially solenoids.
With regards to your flyback question: Flyback protection diodes are typically used in circuits containing inductive loads, like a relay, solenoid or motor. The diode acts to protect the power circuity from voltage spikes produced when the inductive load sees a drop or loss of power. Adafruit has nice diagram illustrating a method for controlling a solenoid with an Arduino, as shown below:
I hope this has helped to answer your question and good luck setting up your breadboard!
Don’t forget, everyone is invited to ask a question!
I was hoping to build a laser engraver out of a 1W diode I have. I’d like to be able to focus the laser into the smallest dot possible both to have a very fine kerf and to bring the maximum heat to the target spot. Could you talk about the theoretical and practical limitations to how small I can make that dot, and different strategies for focusing it? Thanks!
Interesting question! I did a bit a reading up on the lens metrics that govern the minimum diameter of a focused spot and it doesn’t look too hard to derive. Newport has an article specifically on focusing and collimating a laser beam that goes over lens specifications and their relation to spot diameter. You will also note that the minimum kerf is both determinate the focal point and the material that you are cutting. Typically materials with a lower melting point will require decreasing your laser’s dpi in order to lower the cutting temperature, resulting in a better cut with a smaller kerf.
As a numerical example, let’s look at the case of the output from a Newport R-31005 HeNe laser focused to a spot using a KPX043 Plano-Convex Lens. This Hene laser has a beam diameter of 0.63 mm and a divergence of 1.3 mrad. Note that these are beam diameter and full divergence, so in the notation of our figure, y1 = 0.315 mm and θ1 = 0.65 mrad. The KPX043 lens has a focal length of 25.4 mm. Thus, at the focused spot, we have a radius θ1f = 16.5 µm. So, the diameter of the spot will be 33 µm.
This is a fundamental limitation on the minimum size of the focused spot in this application.
Regarding how you focus your laser there are two main ways to do this, electronically and mechanically, and both require an initial determination of your laser’s focal point. If you do not know the specifics of the lenses in your assembly, I would recommend to achieve this distance through simple trial and error. If you set up your laser in a test jig, where the distance from the laser to the sample material can be adjusted, you can conduct a series of tests to determine the appropriate distance by analyzing the cut. I was thinking that using an enlarger for photo development would make a nice Z-axis.
Once you have determined your focal point, you will want to make a focus jig that will allow you to accurately adjust the focus depending on your materials thickness. This could either be a removable piece, or an extension off of the front of your laser module. My Epilog has a removable inverted V touch tool that I use to focus.
The following video shows an Epilog using an electro-mechanical touch tool that uses a spring loaded limit switch to determine the focus. The advantage of something like this is your repeatability and accuracy is much higher then doing it manually. You could easily replicate this by attaching a limit switch to a probe attached to your z-axis and send the feedback to your stepper controller.
Remember, lasers with the power to cut are exceedingly dangerous. Make sure you take every precaution necessary to protect you, those around you and your equipment. Laser beams can extend a bit further then light sabers.
I hope this has helped steer you in the right direction and best of luck with your project!
Don’t forget, everyone is invited to ask a question!
President Obama has launched an “Educate to Innovate” campaign to improve the participation and performance of America’s students in science, technology, engineering, and mathematics (STEM). This campaign will include efforts not only from the Federal Government but also from leading companies, foundations, non-profits, and science and engineering societies to work with young people across America to excel in science and math.
As part of the campaign, this Administration hopes to do a series of events, announcements and other activities that build upon the President’s “call to action” and address the key components of national priority.
Having various projects open source is a great learning tool. I probably wouldn’t have been able to make anything if there were no open source gEDA projects (Evil Mad Sciencemakes a lot of open source projects that use gEDA), or wouldn’t be able to make an Arduino derivative if it wasn’t open source, or wouldn’t have been able to check my voltage regulator circuit against an experts circuit!
My goal for making the RoboBrrd Brain Board v2 open source is: someone will see the board with the artwork, want to put their own artwork on it, realise that it is possible, and learn all about schematics pcbs geda and bash in the process. Of course, hopefully they post a pic up online of their own board too!
For a 1 day school holiday introductory Arduino workshop for beginner 7 – 10 year olds in our Museum, do you have a suggestion for a fun final activity project? We were thinking about something like an monster or robot, built out of strategically placed LED’s on a breadboard, who appears animated eg ‘walks’ or ‘jumps’. Love to know your thoughts…
This sounds like a blast! I like your idea about using the Arduino to illuminate a series of images…I am assuming like a NEON sign. You could even have the kids illustrate individual panels for a storyboard or comic strip, then have them take turns telling the story of their monster/robot while illuminating their animations.
I was also thinking that making a city would be fun. They could use their Arduino’s to light the stop lights, street lamps, billboards, shop fronts, etc. They could be in charge of constructing their block out of say, LEGOs, and use LEDs to light the different sections. You could even get tricky and have them use limit switches to detect a car at a light or someone entering a building or even photo-cells to detect day/night.
Another idea would be to have them use their Arduino’s ability to make music, through its PWM function. We had a lot of fun with our freshman when they get to this section of the curriculum. They are given a small speaker and instructed to recreate a piece of music. We actually had a kid who made his play the Tetris theme song with melody and accompaniment. You could even go a step further and have them use simple buttons on a breadboard and have them make a musical instrument.
Here is a good idea 3 kids had from Children’s Arduino Workshop on MAKE. It could tangent into a “invent your own” activity where you supply the kids with various materials and have them invent a project:
PopFab is a multi-tool for the 21st century. At its heart is a computer-controlled motion platform and a means of attaching various toolheads. These enable PopFab to make objects from a digital plan in a variety of ways: current capabilities include 3D printing (as you are about to see), milling, vinyl cutting, and drawing — with more on the way. PopFab has traveled the world as a carry-on item of luggage to Saudi Arabia and Germany, and within the USA to Aspen in Colorado. We hope that this is only the beginning.
I’m pleased to announce the new APM 2.0 revision, better known as APM2.5! But before you start screaming that you just got an APM 2.0, let me explain that there’s NO difference in performance at all between the two, the board is still the same in terms of functionally and it runs exactly the same code as APM 2.0. We just took the liberty of throwing in a few new universal connectors in there (so accessories can be cross compatible with the new PX4 and protect the user from connecting the cable in the wrong direction), some production improvements that will allows to manufacture it faster and finally we added some protection features to protect it from those reverse polarity/short circuit lovers.
We’re making them at the new Tijuana facility, so we hope that we’ll be able to keep up with demand much better than we have in the past. We’re committed to shrinking all delays, and our investment in the Tijuana facility is just one sign of this.
Hey am a 14 in Ms teenage boy am interested in make ing i love soldering/electronics i read make mag and assort ed blog my parents are not really completely understanding as far as material s needed or tools i don’t want to come off as a yerk or something is there any way to get materials for cheap maybe youth edu tools idk i live in Seattle WA do u know of youth club s in the nw similar to a hacker space but more teen friendly with less 40 year old men hang ing over there computer s and that my parents would feel ok letting me me there alone
Ps. I love Ur teaching method making Ur own classes i love science and math but it seems as if most science is the opposite from educational or interesting thankfully there is the internet
Interesting question! This happens to be a hot topic for us in the school system as we try to get the most for our money, especially when buying materials.
**UPDATE** Henning suggested the following video from Adam Savage discussing “Where to Find Stuff” Thanks, BTW!:
Here are some resources we use:
The “usual suspects”:
Mouser / DigiKey - global catalog and online semiconductor and electronic component distributors.
These are our most popular electronic component distributors. Make sure you pay attention to qty. discounts as often it is cheaper to buy more of something rather then the qty. you need.
MSC - Has over 500,000 items ready to ship same day.
We use these guys for all of our hardware, acrylic, tools, consumables, etc. as they give the school system a pretty decent discount.
Michaels / ACMoore - Are a specialty retailers that offering a vast selection of arts, crafts and floral merchandise to a broad demographic of customers.
I use these guys to by 1/8″ sheets of birch veneer plywood for my projects as you can always find a 50% off coupon online of in the mail
The “not-so usual suspects”:
All-Electronics.com – Has thousands of electronic and electro-mechanical parts and supplies at discounted prices.
These guys are great as they sell “pre-owned” and surplus stuff for cheap.
Kelvin.com – Provides a wide variety of activities at a good price. Every year, KELVIN® strives to provide new and innovative products for technology education, science, robotics, electronics and pre- engineering designed to assist educators in enriching curriculum and motivating students through quality hands-on activities.
I buy most of my balsa, kits and classroom supplies from these guys.
DickBlick.com – Is a premier art supply source for professional artists, students, and teachers, and continues to be a family-owned business.
I buy tissue paper from here as they sell a monster pack for pretty cheap.
This is just a smattering of our resources. Below I have attached the form I use with my students for soliciting donations/discounts. When you are ready to purchase materials for you projects and they are justifiably for a school project, follow the form and see what happens!
My friends and I are working on a VAWT, and we will need a battery bank to go along with it. We would like to be able to use a micro controller to keep track of voltage and amperage over the entire bank (or preferably each individual battery). My question is how can I use a micro controller to do this?
Fantastic! My students just finished installing our 400W vertical axis wind turbine (VAWT) and monitor similarly to how you would like. For this post I am going to assume that you are going to be using 12V car-style lead acid batteries as your bank for the following explanations and math.
In order to monitor the voltage off of your batteries, presumably somewhere between ~11.7V & 14.4V for the car battery depending on its state of charge, you will need to convert the high voltage to a voltage that your microcontroller can handle, typically 5V. One method to accomplish this is through the use of a voltage-divider, which uses a pair of resistors to “scale” the voltage down.
Using the following formula: Vout = (R2/(R1+R2)) * Vin and say a standard resistance for R1 of 10,000Ohms.
I use this reference for finding the closest standard resistor value. In this case the closes resistance equivalent to 5319.14Ohms is 5100Ohms giving you a ~0V to 4.864V (You want to pick the value that is slightly lower then your calculated so as to not go over your 5V ADC limit. i.e. 5600Ohms would result in a max voltage of 5.169V and would potentially damage your microcontroller)
You can also use two resistors in series for R2 in order to more closely match your calculation. i.e. R2 = 5100Ohm + 220Ohm = 5320Ohm which would result in a range of ~0V to 5.001V rather then ~0V to 4.864V.
Your ADC conversion is as follows:
Volts/Bit = 5V / 1024 (10bit) = 0.00489V / Bit
So 14.4V from your ADC would look like 4.864V / 0.00489V/Bit = 995
If your bank consists of more then one battery….say 4 in series, all you have to do is add more dividers. There are two methods of doing this. The first would be to use just one divider on all 4 batteries. This method gives you the most resolution on your max voltage.
The second method is to attach a voltage divider to each battery and use a common ground. This method allows for the monitoring of each battery, although the V/Bit resolution decreases for each successive battery, as shown below.
Now, on to measuring current. A common way for a microcontroller to measure current is with a shunt (a really low resistance high-precision resistor) and a differential microcontroller. If you apply Ohm’s law to the circuit and measure the voltage drop over the resistor you can deduce the current flowing through the bank. Adafruit has a nice little breakout for the INA219 I2C current sensor that can measure up to 26V @ +-3.2A. This might be a bit low power for your application but could act as a good test board. Alternatively, Trossen Robotics has a 30A version that might be a bit more in your range.
I have also had luck with Microchip’s MCP3424′s in the past for such an application, as you can measure the voltage of 3 batteries and the current over the entire bank with one device. You just need to calculate the needed shunt and cooresponding dividers and you are good to go…as shown below:
I hope this has helped to answer your question and good luck with your turbine!
Don’t forget, everyone is invited to ask a question!
Typically, when you see or hear the words “open-source,” what’s the first thing that comes to mind? For many, “open-source” is synonymous with “free software,” but in reality, it’s so much more than that: it’s a movement; a chance to improve lives; a chance for success; a total lifestyle change. In this article, I hope to shed some light on what open-source really is — and more importantly — why everyone should care about it, or at least be aware of it.
Ryan and a group of friends from around the world have decided that they’ll improve their Python programming skills (“We’re not 100% experienced in Python…” says Ryan) and raise some money for the Raspberry Pi Foundation at the same time by doing a 48-hour programming marathon over this weekend, at the end of which they hope they’ll have a game to show us.
Ryan, Ben, Edward and Luke are aged between 12 and 16, and scattered across the globe from Australia to the UK. “We all have Raspberry Pis,” says Ryan; “We all agree this is going to be a big challenge with us having to learn Python as we go, but fortunately we all have experience with other languages which should help us!” They’ll be streaming their progress live throughout the weekend and taking donations at the Raspithon website.
I have some photos and a video of my robot that I had on Show and Tell 14 July 2012. I also found a spec sheet in an old brochure I had on file. Hope it is interesting for you and others that may not have ever seen HeathKit’s robot project. Thanks for the opportunity to be on your Show and Tell program.
Is there a good visual way to see what capacitors & transistors do? While I’ve read the descriptions of what they do, I’m more of a visual person who would like an “ah ha” moment… Thanks!
Prior to teaching our freshman to program microcontrollers, we introduce them to basic breadboard electronics and try to emulate the functions of the microcontroller. It just so happens three of the simple circuits, the LED flip-flop, LED dimmer and transistor amplifier, help to demo the use of a transistor and capacitor. The advantage of using LED circuits, is that it gives you visual feedback. There are also a million other simple circuits that demo transistors and capacitors using things like buzzers, photo-resistors, etc…..I just happen to like these.
The first circuit, an LED dimmer, uses the capacitors ability to store electrical energy (like a battery) and discharge it through the circuit when the primary power is removed. I liked this site, because the author has the circuit’s output connected to a ‘scope and gives a nice visual to the falling voltage, although I don’t condone their breadboard tidiness.
The second circuit, the LED flip-flop, demonstrates the use of transistors to switch on and off a pair of LEDs. This action is controlled by the two base resistors and capacitors in the circuit (RC circuit). When you increase the value of the capacitors the switching frequency slows down and vice versa.
The third circuit, a transistor amplifier, shows a nice demonstration of using a transistor to amplify a high resistance input in order to light an LED. I liked the general description of how a transistor functions as well as using a darlington pair to produce a high-gain amplifier.
These are just two examples that help to visualize the components use. If you are interested in diving deeper, looking at things like filters, you might want to get a scope (i happen to like my DSO nano as it’s cheap and easy to use).
I hope this has helped to answer your question and good luck with your circuits!
Don’t forget, everyone is invited to ask a question!