MightyOhm

If The Art of Electronics is the bible of electronic circuit design, then the Printed Circuits Handbook is almost certainly the bible of printed circuit board (PCB) technology.

I say this because even if you disregard the volumes of useful information inside (much of which I have never seen elsewhere online or in print), this book deserves to win ‘bible’ status thanks to its 1000 pages and phonebook-quality heft!

All joking aside, this book is a great resource for anyone is serious about making good PCBs.  I have worked with PCBs as a design engineer for several years now, and I learned something about printed circuit boards within minutes of opening the cover.  Hours later, I was still flipping pages.

How could I walk away from a book that contains in depth discussions of topics like the difference between water soluble and no-clean flux and how to clean the leftover residue from each?  Ever wondered what the myriad of surface finish options your PCB vendor offers you really mean?  This book will explain the difference between HASL and ENIG, and why you shouldn’t blindly check the box that says “lead-free” without considering the consequences on your assembly process.

This is the kind of stuff they don’t teach you in school, and as a design engineer I have received only glimpses of in the industry.

Some of the highlights of this book for me are:

• The most thorough discussion of PCB manufacturing that I have ever seen (almost 300 pages!).  Want to know how the PCB you just got was made?  One layer or sixteen layers, it’s all in here.
• Lots of information about custom laminates, high density interconnect techniques, microvias, blind/buried vias, plating and surface finishes, solder masks, conformal coating, etc.
• Several charts of current handling ability of PCB traces, planes, and vias.
• A chapter on thermal design of PCBs.
• Lots of information about soldering techniques.  Ever wondered how soldering works and what flux really does?  It’s in here too.
• Seven (!) chapters on design, manufacturing, and test of flex circuits.

Be forewarned that the technical level of this book is fairly high.  It is clearly targeted towards people working in the PCB industry, but most engineers and even serious hobbyists would probably get something out of it.  That said, this is definitely not a book for beginners!

(And to the other design engineers out there: Want to one-up the manufacturing and reliability guys in the break room?  Read this book!  )

Printed Circuits Handbook (McGraw Hill Handbooks)

This all started last year, when I was playing with an ATmega168 microcontroller and did something silly.  I programmed the RSTDISBL fuse bit, which effectively makes it impossible to reflash the chip using an ordinary (serial) programmer.

Instead of giving up and throwing out the “dead” chip,  I decided to try to revive it using an obscure high voltage parallel programming mode that isn’t supported by most AVR programmers.  Armed with my Arduino and the ATmega168 datasheet, I quickly designed and constructed a programmer using parts I already had on my workbench.

A few hours later, I tested my new programmer and it worked!  I revived my “dead” AVR by using spare parts and a few lines of Arduino code.  That week I published the schematics and Arduino sketch to the site and called it my Arduino-based AVR High Voltage Programmer.

The response was overwhelming.  Since I first posted the design, many people have built their own and used it to fix their “dead” AVR microcontrollers by restoring the fuse bits to sane values.  I even received several requests for a PCB and/or kit based on the design, which got me thinking…

Today I’m proud to introduce:

The AVR HV Rescue Shield

The AVR HV Rescue Shield is a high voltage parallel mode fuse programmer for Atmel AVR microcontrollers.

It currently supports the ATmega48/88/168/328 series and the ATtiny2313.  The Rescue Shield does everything my original AVR High Voltage Programmer does, and a lot more.  I think the new features make this a really useful tool for anyone working with AVR microcontrollers.

New features include:

• Custom 2-layer PCB with silkscreen and soldermask.  No more hacking and modifying perfboards to fit Arduino’s nonstandard pin spacing!
• Onboard 12V DC-DC boost converter eliminates the need for an external 12V power supply
• Support for two of the most common families of AVR microcontrollers, the ATmega48/88/168 and ATtiny2313
• Support for programming the extended fuse (EFUSE) byte.
• A new interactive mode, where desired fuses can be entered using the Arduino’s serial port.
• Separate Ready and Burn indicators
• Protection resistors on every single data, control, and supply line to the target AVR, meaning that your Arduino and AVR should survive any mishaps during programming, including inserting the AVR backwards or off by 1 pin.

I spent considerable time testing each new feature and documenting the Arduino sketch.  I hope that you’ll find that the finished product was worth the wait!

Ordering instructions:

To purchase bare PCBs and kits, head over to the AVR HV Rescue Shield product page.

100 wonderful, amazing people have joined the Flickr Printed Circuit Boards Group since I launched it in July of last year!

The pool features over 400 pictures of printed circuit boards, many of them CC licensed.  There’s a little bit of everything, from homebrew board fab to PCB jewelry and even miniatature cityscapes.

If you have some cool PCB images of your own, add them to the pool!

One of my favorites: Car Park or Printed Circuit Board?

Big news – the AVR HV Rescue Shield PCBs arrived yesterday!  I’m currently testing them and will post information about kits for sale as soon as I verify that everything is working properly.

This is actually the second spin of the PCB but the first to bear the ‘Rescue Shield’ name.  The first spin was a one-off prototype to check a couple things out, mostly related to the 5V to 12V step up converter.  That design allowed me to fix a couple bugs before doing a production run with the improved design, show below.

So far all I can say is that the step up converter works perfectly.  (Yipee!)

More details to come!

Here’s a really cool Instructable about using a flexible copper-clad material called Pyralux to make flexible printed circuit boards.  You could make some really cool business cards with this stuff.

DIY Flexible Printed Circuits

(via makezine)