Interested in setting up a cool screensaver that will display a continuously changing collage of photos from the Electronics Workbench and Printed Circuit Boards flickr pools?

Here’s how to do it in Windows:

First, install Picasa.  This should install the Google Photos Screensaver.

Next, open the Windows Screen Saver Settings control panel. (Type “screen saver” into the Windows 7 search bar, open the Windows Control Panel and navigate to Appearance and Personalization->Change screen saver, etc.)

Select the Google Photos Screensaver and click Settings…

Set the Visual Effect type to Collage, and adjust the Change picture every… slider to taste – I suggest starting at 3.0 seconds.

Uncheck all options except Photos from public sites, then click Configure…

Copy and paste each of the following RSS feeds into the Additional photo feed sources dialog, and click Add after pasting each one.

http://api.flickr.com/services/feeds/groups_pool.gne?id=812901@N20&lang=en-us&format=rss_200

http://api.flickr.com/services/feeds/groups_pool.gne?id=1767402@N25&lang=en-us&format=rss_200

After adding both feeds, make sure the entries for each them are checked and click OK. Then click OK again to return to the Windows Screen Saver Settings window.

Click Preview and photos from the Electronics Workbench and Printed Circuit Boards flickr pools should start appearing on your screen. If so, the screen saver is working.

Click OK to close the control panel and you’re done!

If you’re interested in setting this up in OS X, the process is very similar – just add the RSS Feeds to your screen saver settings as documented here.

Have fun!

I’ve been making some changes and additions to the MightyOhm Wiki over the past few days.

To complement the awesome list of surplus electronics shops, I started creating wiki pages for the various projects I have previously documented on the blog.

Last night I added a list of cheap PID controllers to the wiki page for my DIY PID-controlled Soldering Hotplate.  (Backstory: the PID controller on my hotplate quit working this week and I’ve been shopping for a replacement!)

I have also  been adding more information to the PCB resources page, including where to order cheap solder paste stencils and resources for making test fixtures.

More to come…

Laen of DorkbotPDX has been running a PCB proto service for some time now, and I finally got a chance to try it out this month.

The pricing is simple.  For 2-layer boards, it’s $5 per square inch for three (3) PCBs, with no setup charge, and shipping is free.

The tunaround time is typically 9 days + first class mail shipping, which ends up being just under two weeks total fom PCB release to delivery in Austin.  This is pretty good for a group order, and signficantly faster than BatchPCB (based on my experience).

The only downsides that I am aware of are:

• PCB orders only go out once a month, unless there is enough demand to justify a 2nd run.
• If you wait too long, the panels can fill up.  Again, if there is enough demand, sometimes a 2nd panel can be added, but don’t count on it.
• The soldermask and silkscreen can be any color (and you don’t get to choose!)  BatchPCB at least guarantees the standard white/green.

4-layer boards are available as well, but at a higher cost ($10/square inch) and less frequent intervals.

Entries for the next PCB order are due on October 25th.  The more orders Laen gets, the more likely he is to continue the service, so if you have some designs you’ve been thinking about but have been put off by expensive PCB costs, finish them up and get some boards made!

I want to thank everyone who bought kits and PCBs. Thank you for supporting me and the site!

Rather than reorder new boards of the existing design, I am taking this opportunity to re-evaluate my approach to a couple things, with the goal of reducing the BOM cost and lowering the overall cost of the kit.

The bad news is that this means there won’t be any more kits in stock in the short term. I’m planning to release a new PCB design within the next couple weeks, which means kits would be in stock within about a month. Because this is a busy time for me, I can’t promise specific dates, but I will do my best to keep the process moving because I know there are people waiting for the new kits.

If you need a kit right now, I believe Solarbotics still has some in stock.

Otherwise, stay tuned for updates.

And again, if you bought a kit, or even if you built the DIY version with spare parts and helped spread the word, thank you!

- Jeff

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.

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?

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)

Ladyada has a PCB Cost Comparison Calculator that shows the significant differences in price between various low volume PCB vendors, but what’s missing from the chart is the answer to: What vendors are people actually using?

If the cheapest fab house is also the best, obviously the more expensive vendors wouldn’t be around, would they?  Unfortunately, it’s usually not that simple, cheap usually means slow, or low quality, or both.

I know that some visitors to this site make prototype PCBs at home and others send them out to be fabricated.  How do you get your prototype boards made?  Vote below.