Decoupling Capacitors Explained -or- If You Like It Then You Shouldn’t Let It Ring Like That

If you’ve ever wondered how decoupling and bypass capacitors work, or why you should use them on every digital circuit, you need to check out Bertho’s excellent tutorial on the subject. He writes:

While enjoying the 7400 contest, it occurred to me that many of the submitted logic designs lacked some of the most elementary safeties to ensure a working result. One of the most disregarded aspects of the designs was the lack of bypass capacitors. Then, with an article about Murphy’s law linking a Maxim application note, it was decided to write a bit about decoupling and bypass capacitors.

As a person, who can be considered “old” in this line of work, I have experienced the problems of missing decoupling first hand. My first high-speed build was in the mid-eighties as an apprentice at a large electronics firm. The design I was building, a digital frequency measurement, used 74Fxx logic at a speed of 11MHz (which was very fast for the time). It was wire-wrapped on a double euro-card size board and used about 40 logic chips. When the time came to turn it on, I noticed that it didn’t work as expected and all kinds of stuff happened all over the place. After checking the build several times I talked to my supervisor about the problem and he just looked at it and said: “There are no bypass capacitors; mount them on all chips over the power supply and we’ll talk then.”. Completely bewildered I did what he said and, as a miracle, everything just worked. Why would seemingly inert capacitance on the power supply make things work?
My supervisor then told me all about switch/surge currents and inductance of the wiring and went on to tell the tale of decoupling. I admit that it took several years before I really understood what he was talking about, but the lesson was learned: always put capacitors on the power supply of logic chips.

This is probably one of the best discussions of the topic that I’ve ever seen: thorough, well-written, and easy to understand, even for a beginner. The reactive spaghetti monster is a wily beast, and it creeps up everywhere. Many thanks to Bertho for writing this great article about how to defeat him.

[via HaD/Twitter]

Filed under: EE — by johngineer, posted October 26, 2011 at 12:23 pm


Robotic Halloween Mask #electronichalloween

Robotic-Halloween-Mask

Robotic Halloween Mask. Noel writes…

My first halloween robotics/electronics project. I always wanted to do something for the halloween so I made this one. I had an old scary mask from last year and I’ve added two styrofoam balls inside to “fill it up”. I’ve mounted 2 LEDs (one for each eye), and then added a PIR sensor as well. I wanted to create something that moves as well as something that has sounds so I’ve bought a WAVE shield from Adafruit a few weeks ago.

Soldering time. I’ve started soldering the wave shield. The board is pretty slick and very well made. I also bought the Panavise Jr. This is so worth it. Soldering with a panavise is way way better than a 3rd hand tool.


W5W5B-1

View all our Electronic Halloween posts here! From now until 10/31/2011 use the code HALLOWEEN on check out to get 10% off anything in our “EL Wire/Tape/Panel” category.

Filed under: arduino,halloween — by adafruit, posted at 10:44 am


Make: Live’s Halloween Party tonight at 9pm ET / 6pm PT

Make: Live’s Halloween Party tonight at 9pm ET / 6pm PT. Matt writes -

Are you still undecided what you’ll be for Halloween? Tune in to Make: Live’s Halloween Party tonight at 9pm ET / 6pm PT for a little inspiration. This show is PACKED with fun stuff! Designer, craftsperson, and Emmy award-winning puppeteer Anney Fresh will join us at the party to show and tell with her fantastic costumes and characters. We’ll also have members of local hackerspace NYC Resistor showing off their electrified, motorized, LED-adorned and otherwise hacked pumpkins. Becky will be sharing her “Tricks for Halloween Treats” and we’ll also have a costume parade. If that’s not enough, Becky and I will be opening the show by revealing our Halloween costumes with a tip of the hat to one of our favorite TV shows

Filed under: halloween — by adafruit, posted at 10:29 am


Visual Micro – Arduino for Visual Studio

Arduino For Visual Studio Demo

Visual Micro – Arduino for Visual Studio.

A complete Arduino development system for Visual Studio 2008 and 2010.
Arduino for Visual Studio is a small free addin for Visual Studio that
provides fully featured Arduino Development.

Developers no longer need to use the Arduino Ide. We can code and upload to
any Arduino microprocessor using Visual Studio. (not available in the
express versions).

Visual Micro is based on the operational procedures of the Arduino IDE and
follows the rules applied by the Processing IDE for Arduino. This allows the
user to load a standard Arduino sketch into the Visual Studio environment
without having to make changes to the sketch or .PDE files

Visual Micro is the most comprehensive and easy to use build environment for
Arduino to date. The Visual Studio addin includes many of the features you
would expect to find in Visual Studio but that are not usually available in
the Arduino IDE.

Some examples:-

1 Compiler Error GoTo Source Location
2 Find In Files
3 Full Arduino Intellisense for the sketch, all cores and libraries
4 Options to “Include All Arduino Files” in the current sketch project. This
makes learning and exploring very easy and does not cause compiler problems.
5 Auto pause and re-start serial during upload (unless using ISP/programmer
which is fully supported)
6 Burn Bootloader
7 Multiple “Serial Viewer” Tool Windows
8 F6 Build, F5 Build & Upload

Via the forums!

Filed under: arduino — by adafruit, posted at 9:21 am


Meet the TED 2012 Fellows – 2 are open-source hardware makers!

2012 Photostrip

2012 TED fellows great list of folks, two of them are very familiar to the open-source hardware community!

Ayah Bdeir (Lebanon | US) – Engineer + artist
Lebanese artist, inventor and founder of littleBits, an open source system of pre-assembled circuits that snap together with magnets — making learning about electronics fun, easy and creative.


Bre Pettis (US) – Maker
Inventor, maker, and founder of MakerBot Industries, a company producing the Thing-O-Matic, the first affordable 3D printer.

Filed under: open source hardware — by adafruit, posted at 7:44 am


Reclaimed wood art by Michelle Peterson-Albandoz

Pt 101828

LongView Gallery – Washington DC Art Gallery via colossal art.

Michelle is well known for her wood constructions on panel and sculpture made from reclaimed wood from urban areas. To be exact, chaotic materials that people just discard. Most of us don’t even see these objects that become cohesive panels inspired by nature. We just see faded 2 by 4′s in a pile by the empty lot, or an eye sore. Michelle takes a different view. The more beaten and abused the wood, the better it translates alongside other pieces. The weathering of the squares and strips that make up her art panels create a certain flow, a natural and architectural one.

Filed under: art — by adafruit, posted at 7:31 am


The race for makers to remake the “Remaking of the Thermostat”

Nestjp2-Popup

At Nest Labs, Ex-Apple Leaders Remake the Thermostat @ NYTimes.com.

Nest Labs, based in Palo Alto, Calif., and founded last year, is announcing its offering on Tuesday, and plans to begin shipping the $249 thermostat by the middle of November.
Outsiders who have tried out the product are impressed by its stylish design, ease of use and advanced features, like motion-tracking sensors that detect whether people are present and adjust room temperatures accordingly. But it remains to be seen whether consumers and contractors will pay more for a high-tech thermostat, when good enough has been good enough for decades.

The big story will be the the thousands of makers that are just going to make their own (different/better) open source versions quickly after this is released. We already had a few customers email us, they’re working on it now. “DIY home automation” are the top show-and-tell projects each week too. We’ll probably pick up one just to take it apart :)

Filed under: random — by adafruit, posted at 7:25 am


What can you do with the ADAlights? THIS!

From the forums: What can you do with the ADAlights? THIS!.

Filed under: leds-lcds — by adafruit, posted at 7:22 am


Entrepreneurs Who Go It Alone

Entrepreneurs Who Go It Alone — By Choice – Entrepreneurial Insights @ TIME.

…during the recent economic slump, more Americans have started businesses than at any time in the past 15 years, according to the Kauffman Foundation. The Kauffman Index of Entrepreneurial Activity, an indicator of new business creation in the U.S.,shows that .34 percent of American adults created a business per month (or 565,000 new businesses) in 2010. That’s not entirely surprising given the state of the economy: Entrepreneurship is often a choice for people who were laid off and can’t find work.

We are seeing more one-person shops starting kit businesses as well lately.

Filed under: kits — by adafruit, posted at 6:44 am


7400 competition: Entries and reader’s choice

7400-Ic-Dark-W6002

7400 competition: Entries and reader’s choice @ Dangerous Prototypes.

Here’s a (hopefully) complete list of entries in the Open 7400 Competition. Please share your favorites in the comments below, your favorites will receive a special reader’s choice prize. Voting ends in 24 hours. A few commenters will receive free PCB codes as a thank you for voting.

Massive list! And a customer just sent in this one to us to check out “The 7400 Logic Electronic Etch-a-Sketch!“….

Filed under: EE — by adafruit, posted at 6:37 am


xkcd: Everything

Everything

xkcd: Everything.

Filed under: art — by adafruit, posted at 12:05 am


Passive Walking Robot Propelled By Its Own Weight

Passive Walking Robot Propelled By Its Own Weight – Nagoya Institute of Technology, System Instruments…

Filed under: robotics — by adafruit, posted at 12:01 am


ASK AN ENGINEER 10/22/11 (video)

ASK AN ENGINEER 10/22/11 (video)

Filed under: ask-an-engineer — by adafruit, posted at 12:01 am


SHOW-AND-TELL 10/22/11 (video)

Pt 101824

SHOW-AND-TELL 10/22/11 (video).

Eyepiece

http://www.nabiltewolde.com/
http://www.modelesis.com/embeddedbliss/2010/01/hotwater-intro/
http://baldwisdom.com/soul-b-gone-a-super-camera-remote/
https://github.com/RobotGrrl/robobrrdIRC
http://www.johngineer.com/blog/?p=637

Filed under: ask-an-engineer — by adafruit, posted at 12:00 am


New blogger – Bill Porter

Hey guys! I’m excited to join the folks at adafruit as a new writer for their blog. My name is Bill Porter and I’m an electrical engineer for the U.S. Navy. Can’t tell you much about my 9-5; basically I design and build robots. This is a picture of my latest project:

My main job is not why adafruit took an interest in me so I’m not going to go into any more details. What did catch their eye was my extra-curriculars and passion to get kids interested in science and engineering. My main program, the ‘Science Brothers’ has been covered by adafruit before. Right now it is just a road show that travels to local elementary schools free of charge to show off some cool science demos to their kids, but we are working on expanding it to include more. The program is half funded by NDEP (National Defense Education Program) and half volunteer. In fact, most of the demos are built in my living room. If you like you can watch a full length video of the program on it’s website. Besides schools, we also make regular appearances at our local science museum and on local news stations all to promote the program and STEM education.

Besides the Science Brothers and my ‘real job’ I also dabble in embedded electronics, arduino library writing and robot building at home, and most of my projects are documented on my own blog. I’ll be here posting items related to education and how we can bring the wonderful world of electronics from on-line to in-class.

Filed under: educators — by Bill Porter, posted October 25, 2011 at 6:50 pm


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