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AJ Cooper
Wrench-turning hardware and semiconductor geek
Wrench-turning hardware and semiconductor geek
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#samsung   #galaxygear   fails the "tape test" in stellar fashion.  When building a product, this type of thing has to be carefully considered.  What do you guys think happened at the factory to cause such a bad adhesion problem?  Surface prep, materials compatibility, cleanliness?  Anyone else want to try this with their Gear?
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2014-03-11
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Ever wonder how to design inductively coupled amplifiers?  This design brief describes one such project for a Class-E amplifier.  Most textbooks fall off at this point so I wanted to share how I went through this design.  The first big "Aha" moment was learning to use impedance transforming networks.  The second was inductor biasing the output transistor to resonate with the internal capacitance.  What neat things have you all learned about RF circuits?

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Just put up a quick design brief for an active Bessel filter implementation.  They come in really handy when you have an input signal where you want to preserve the shape of the waveform (like a pulse).  Use this as a reminder that there are other filter types than Butterworth.

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Had the fortune of hearing the guys from HP Labs talk about their glasses-free 3D today.  The most clever part of the design is the diffraction gratings that create an array of directional light cones.  Each one of those cones then passes through a conventional (high density) LCD layer that blocks or attenuates light from a particular direction.  

What I found really striking was the comment David Fattal made during our side discussion.  One graphical pixel is an 8x8 array of 'directional' light cones so you need 64 LCD pixels for every graphical pixel.  Instead of needing 64 times the backlight power, the brightness is about the same because it is directed over a small solid angle for any one viewing position.  We talked about the display essentially becoming very dark when viewed from a large off-axis position.  That wasn't the case with the Gen 1 displays they brought to share (which looked best at about 30 degrees off normal and just strange at 80 degrees off normal) so maybe more pronounced for the parts still in lab.  Great to see +Sonny Vo and meet David Fattal, and Zhen Peng.  Also met some great locals promoting a user metrology facility at +NASA Ames Research Center.  $90/hr for XPS? Now we're talking!
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Black walnut table with glass inlay
http://imgur.com/a/5tgkA
Finally getting around to posting these photos of this table I made.  It was a present for my sister's wedding.  The tree from which it was made grew in our yard as kids.  One of my occasional non-electrical projects.

Hardware is kinda quiet in the Bay Area.  That is, quiet in comparison to the software behemoths that are here.  Hoping to hear some more about wearables at Silicon Valley Innovation Summit tomorrow and Wednesday.  I'll be one of the volunteers helping do odd jobs to save the $2k registration price.
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I've been thinking a bit about what Vinod Khosla said last week regarding failure.  He said that failure is irrelevant and that people only really remember success.  There was a great follow up question about whether that's only the case AFTER one has become successful.  Ultimately, it came down to surviving long enough until you get lucky.  How do you get lucky?  By setting yourself up for it.  By being in the right places, meeting the right people, and not being invisible.  
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Just listened to Vinod Khosla give a talk on the Google campus.  Biggest take aways:  Don't work for big companies that aren't Google, smart people don't stay unemployed long, do what you love and send Vinod your resume.  Overall, a really positive talk!
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Really enjoyed SEMICON West last week.  Met some really great people from Kurt J Lesker, Oxford Instruments, Pfeiffer Vacuum, MKS Instruments, Inficon, Frontier Semiconductor, and Muegge.  Thanks to all those who reached out and shared their experience!
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This is one formerly very broken cell phone screen (photo by newly repaired phone).  A Samsung repair costs far more than the <$30 this one did.  Sure, I maybe I cheated by covering the display in high-temp Kapton tape and I may have monitored temperature with an infrared thermometer.  Heated the display to an electronics-safe 85C and carefully removed this broken screen.  Slap the new one on, heat it again to 85C and press it flush.  Beautiful new display for a sixth the cost of sending it to Samsung.  Sweet.
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