If you study electrical engineering, you will invariably be introduced to something called “Norton’s Theorem” (also known as a “Norton equivalent” circuit), most likely in your first-term electrical circuits class. Norton’s Theorem, and Thevenin’s Theorem, from which it is derived, are pretty handy things to know when you’re working out circuits by hand. Both of them allow you to take a complex network of resistors, capacitors and inductors (collectively called impedances) and simplify them into a single impedance in series or parallel with a voltage or current source, respectively.
E. L. Norton, the fellow who worked out the eponymous theorem, was an interesting guy. While researching something completely unrelated, I stumbled on this bio page about him from the ECE department at Rice University, courtesy of Prof. Don Johnson. It’s a fun and fascinating read. I love this quote:
Norton was something of a legendary figure in network theory work who turned out a prodigious number of designs armed only with a slide rule and his intuition. Many anecdotes survive. On one occasion T.C. Fry called in his network theory group, which included at that time Bode, Darlington and R.L. Dietzold among others, and told them: “You fellows had better not sign up for any graduate courses or other outside work this coming year because you are going to take over the network design that Ed Norton has been doing single-handed.”
Norton’s Theorem, a fundamental tool in network analysis, was basically buried in a memo (pdf) — Norton himself never published it in the wider EE community. My guess is that his work was so influential among his colleagues that eventually other BTL (Bell Telephone Laboratories) guys started citing him in their own work in professional journals. And so the legend was born. Also interesting to note: A German telecom engineer named Hans Mayer published the same theorem, later in the month of November, 1926, so in Europe the circuit is known as a “Norton-Mayer equivalent.”
Another +1 for Norton, he could draw a pretty rockin’ frequency response plot by hand (see above).
There’s a huge community of Roomba hackers online. What’s your take on that? We’re a company that was founded by engineers and really loves the fact that [a Roomba hacking] community exists. Why do you think we made it so you can take the top off and find a beautiful serial port? Why do you think we published the API for the serial port? It’s an expense but it was the right thing to do. People should hack robots. There is a cottage industry of people making money from Roomba accessories out there today. I hope that it will grow over time. People are getting excited and learning about robotics. Roomba is a durable, dependable and affordable platform for doing robotic research.
Topics include: Adafruit and Arduino mention on NPR’s Science Friday, Teensys back in stock, badges back in stock, Apple’s Adafruit screws, Bunnie to testify about fair use? Atmel has a store, This Old Pick and Place, Pick and Place tutorials, JOBS board and featured jobs, new kit – THE BRAIN MACHINE, the TRIPLE NICKEL timer, how we take photos using a foot pedal, your questions, trivia, a cat and more.
What is “Ask an engineer”? From the electronics enthusiast to the professional community – “Ask an Engineer” has a little bit of everything for everyone. If you’re a beginner, or a seasoned engineer – stop in and see what we’re up to! We have demos of projects and products we’re working on, we answer your engineering and electronics questions and we have a trivia question + give away each week. Mosfet the cat stops by too. Previous chats can be viewed at http://www.adafruit.com/ask
Want to put a little geek in your Halloween? We’ll get tips from the folks at Instructables about incorporating some engineering DIY into your spookfest, from tricked-out costumes to computer-controlled, live-tweeting, Silly String shooting, jackolanterns.
Greetings Ladyada and PT, I wanted to say thank you very much for having such a wonderful site. You have been very inspiring over the years as I have worked on my electronics projects and such. You helped motivate me to better document my projects, and to make them available as open source projects. With this in mind, I am excited to announce my first open source project, a color-changing lightsaber (fully documented and 100% open source). Check it out over at http://nbitwonder.com/projects/rgbsaber, …
The latest episode of the Robots Podcast interviews Chris Anderson, the founder of the largest amateur UAV community and one of the largest robotics communities, DIY Drones and Editor-in-chief of WIRED. As some of you may know from somepreviousposts, DIY Drones is behind the well-known Arduino clone ArduPilot which allows easy autonomous stabilization and navigation of UAVs. DIY Drones is also a major proponent of open source hardware. For more information on making flying robots, the risks of putting this technology into the wrong hands and some crazy anecdotes read on or tune in(mp3)!
We put these back in stock today, the were taken out during some crazy PS3 hack that have have now blown over.
The Teensy is a complete USB-based microcontoller development system, in a very small footprint! All programming is done via the USB port. No special programmer is needed, only a standard “Mini-B” USB cable and a PC or Macintosh with a USB port.
Key Features:
USB can be any type of device
AVR processor, 16 MHz
Single pushbutton programming
Easy to use Teensy Loader application
Free software development tools
Works with Mac OS X, Linux & Windows
Tiny size, perfect for many projects
Available with pins for solderless breadboard
Comes with assembled Teensy board (ATmega32u4 with bootloader preinstalled) and header to allow easy breadboarding. We suggest using AVR-gcc (like WinAVR) with the LUFA library or ‘Teensyduino’ Be sure to check out the multiple resources available at PJRC!
This project tutorial will show you how you can convert a console game pad into a USB keyboard mouse for playing games on your PC. The USB game pad can be used with nearly any software, such as a MAME emulator, game, simulation software, or for custom user interfaces. We’ll start by turning the buttons of the game pad into keyboard buttons, so that pressing ‘up’ is converted into the ‘U’ key, for example. The firmware is easily adaptable, so you can adjust it for whatever software it will be used with. Then we’ll make the project more interesting by adding an accelerometer. This will allow the game pad to be used as a mouse by tilting it! This tutorial including the original code and Portal video is by Devlin Thyne! Rock!
You’ll need the following in order to build the project:
Teensy – This is a very small microcontroller board that can act as a keyboard/mouse
Triple-axis accellerometer – We’ll be using the nice ADXL335 on a breakout board. You can skip this if you’re not planning to add in the mouse capability
USB cable with mini-b connector – to attach to the Teensy for plugging into a computer!
Ribbon cable – for all the soldering connections. Rainbow cable is the easiest to work with as its color coded
The most common timer chip is the 555, but it comes in a few flavors!
555′s are commidified, you’ll see them made by dozens of manufacturers.
Pretty much any ’555 is pin compatible with different power ratings, voltage ratings, max frequency etc.
NE555, SE555 LM555 is the ‘original’ TTL version but is power hungry, and needs 4.5V or higher to run! In general the CMOS versions are better
The LMC555/TLC555 is the lighter-weight CMOS version, it can run as low as 1.5V, with much less power dissipation. These are your bread and butter!
The TLC551CP is ultra low voltage, can run on 1V, making it perfect for single-alkaline-battery operation
We have links for purchase, and of course the EagleCad library reference. Its all in the wiki so if you have some other 555′s you like or other purchase links please add them in!
The Engineering Manager provides leadership, inspiration, direction, coordination, scheduling, work approval and hands-on engineering contribution for a present staff of three engineers. Central to all efforts will be a customer focus on commercial users who design products using the Propeller. Parallax business is evolving to increase design-in support of our commercial customers. This position will work closely with customers who design products using our Propeller chips. As the department and business increases, additional staff will be added to assume the same roles and the Engineering Manager will provide less hands-on engineering and increased direction and coordination to the engineering staff.
The main type of products that will be designed in our Engineering Department include Propeller-based products that also serve as open-source reference designs (i.e., PropScope, Propeller Web Server, etc.). Other less frequent designs (accessories for any microcontroller) include sensors, motor controllers, Ethernet/internet/WiFi compatible devices, and small signal analog interfaces. Some of these designs also have mechanical dependencies such as enclosures, mounting brackets or robotic assemblies. This requires an understanding of design dependencies (a thorough understanding of SolidWorks is not necessary).
Want a live tutorial on how to hack an Xbox by the guy who actually wrote the book on it?
If so, you should plan to attend what likely would be the nation’s first federal jury trial of a defendant accused of jailbreaking Xbox 360s, installing mod chips that allow the console to run pirated or home-brewed games and applications.
Celebrity geek Andrew “Bunnie” Huang, the designer of the Chumby and author of the 2003 title Hacking the Xbox: An Introduction to Reverse Engineering, has agreed to testify for a southern California man charged under the anti-circumvention provisions of the Digital Millennium Copyright Act.
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