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Published on: August 10, 2013 / Comments: None

Oscilloscope XY Fun

I stumbled on this oscilloscope demo that is actually done on a Rigol DS2072 digital oscilloscope.  Normally you see these types of demos on oldschool analog scopes.  The demo is played via a sound card hooked up to 2 channels of an oscope in XY mode.  In XY mode, one channel moves the X axis, one moves the Y axis.   There is actually a flac (lossless compressed) audio track downloadable here if you wanted to try it for yourself.

If you’re into this kind of thing you’ve probably seen the Youscope demo, it’s a classic!


Published on: August 6, 2013 / Comments: None

Enabling hardware random numbers on your Pi, and explore randomness

Recently a driver has been released for the Raspberry Pi that enables the hardware random number generator on the Pi’s processor.  The numbers are generated by tiny thermal fluctuations in the processor.  On the linux side after the driver is loaded a new /dev node appears.  Once installing the rng-tools rngd it will seed your /dev/random with entropy from the hardware random number generator.

Some cool things are to visualize your random data, or to listen to it.  Check out the article or complete instructions and a little theory.

Published on: August 5, 2013 / Comments: None

Wrap your head around function pointers in C

Not to cause a language-preference war, but if you do programming you’ve probably written or thought about writing in C.  One very powerful tool in C  is utilizing function pointers, but they can be tricky.  Luckily Dennis took the time to create a useful write-up on the topic.

You’ll see by reading the article that using simple function pointers is a lot like using regular pointers (but as functions, lol).  However it gets more tricky when you start dealing with function arguments and return values.

If you need to take a step back, Dennis has some other useful tutorials you might be interested in.

Thanks Dennis!

Published on: August 5, 2013 / Comments: None

Build a Michigan Mighty Mite

This looks like a fun old-school build.  The Michigan Mighty Mite.  It’s a shortwave transmitter, has an antique vibe to it.  Defiantly something to build if you are getting into RF or wanting to learn more about RF.

The only part you probably don’t have is a variable capacitor, however the article does state you can just keep piecing together regular caps until you are happy with the rf output.  Oh and you’ll have to wind your own coil :)



Published on: August 1, 2013 / Comments: None

Don’t hate just because I love negative feedback

On my never-ending quest to learn more of the why’s and math around electronics, I stumbled on this great article pertaining to negative feedback loops in respect to audio and amplifiers.  Bruno makes for the argument that you cannot have too much negative feedback.  Knowing little about the topic itself, I know negative feedback can be used to correct distortion, but I don’t exactly understand too much vs too little.

My research into this topic tells me there is some sort of vim vs emacs war waiting to happen (Ugh.).  Bruno attempts to show the math that proves his theory.

Interesting read.  Check it out here.

Published on: July 28, 2013 / Comments: None

Some solid tips for designing PCB’s

Michael has put together a really sweet in-depth run down of designing a PCB.  If you’ve never designed your own circuit board but you have done some breadboarding then you need to get with the lingo.  What the hell is a blind via ?  Go check out the article and find out.  If you’ve made boards before, there still might be some tidbits that you didn’t know or at the least take in some of Michael’s process for visualizing how the board is going to go together before laying it out.

This was only part 1, he has a landing page ready for part 2 but at the time of writing this article it wasn’t up yet.  I look forward to reading it when it’s available.

Published on: July 27, 2013 / Comments: None

Magnets (on stepper motors) How do they work ?

I’m always a big fan of learning more about  Why  vs  How .  Once you understand what’s really happening inside the black box, you can interface with it better after you really know its needs.  Siddharth  is here to school you and teach you more about stepper motors.  If you’re thinking about building things like robotic arms, or 3D printers you’ll most likely use a stepper motor.  DC motors are good for most things, but stepper motors allow you to get accurate with your precise location while giving you lots of power at the same time.

This is one of those articles you need to bookmark for later when you are actually working on something using steppers.  The diagrams showing the differences between 4/5/6 and 8 wire configurations, and Full step, half step and microstepping are going to be valuable to refer back to.  I sware every time I hook up a 6 wire stepper to a 4 wire controller I have to google it each time.

Siddharth also has a follow-up article where he interfaces the stepper to a PIC microcontroller.