Saturday, January 28, 2012

New PCB!

The PCB's from ExpressPCB arrived, and I finally got some time to solder all the components.  If all goes well, this should be a much more stable solution.

PCB layout design

Front view

Back view.  Testing out a new logo.

The fully populated board!

I applied power and the LED came on as it should.  Voltages to the Teensy controller and the two multiplexers (mounted on the red breakout boards) is correct as well.  There's still a bit more testing to be done before I hook up all the buttons, but so far I'm happy with how it's coming together.

Wednesday, January 18, 2012

Custom PCB design complete!

It's always exciting when you create something and test it for the first time.  It's not unlike trying a new baking recipe.  Put yourself in that magical state of limbo where all the ingredients have been mixed, the dish is assembled and has just gone into the oven.  You're confident that you've followed the recipe correctly but you just can't quite silence that little voice in the back of your head telling you that you won't know for sure until the oven timer dings. 

That's where I'm at right now.

I checked and re-checked the PCB design, and when I was finally satisfied that there was nothing else I could do from this end, I submitted my order.  I'm using a site called ExpressPCB.  I've talked to a few people who have used them before and they have had good results, so I'm optimistic.  I can say for certain that their schematic capture and PCB layout software is far easier to use than the alternative (*cough* - Eagle - *cough*).  One other nice thing about this particular PCB service is their unbelievably fast turnaround time.  I expect to see my boards within 4 to 5 business days.

If you're curious, here's what a completed PCB design looks like.

This is a 2-layer Printed Circuit Board (PCB).  That means there are actually two layers of "copper", or conductive metal traces.  These are analogous to the "wires" in a wire-wrapped board.  In the picture above, the green layer is actually printed on the bottom of the board and the red layer is on top.  Note the reversed green text, indicating that this text will appear on the bottom of the board, and will look correct when viewed from underneath.

The yellow text and lines are called a "silkscreen" layer, and are printed last, after the board is completely fabricated.  These markings exist to assist in component alignment and board identification.

The board is designed, and the order placed.  All there is to do now is wait. 

...and I hate waiting. 

We're famous!

Last night, those of you in the San Francisco Bay Area may have seen a human interest story during the 6:00 news that looks familiar.

That's right, we made the news! 

I'll post the link below.  Head over there and show your support for the fine folks at ABC San Francisco, they do great work!

You can find the video here.

Tuesday, January 17, 2012

Redesign underway!

It's been a slow few weeks in the world of the Frankenkindle.  Having an infant in the house, while amazing and stressful and miraculous, leaves little time for electronics tinkering. 

The Frankenkindle was intended to be a Christmas gift for my sister, but something went sideways when it everything was transferred from the old wooden stand to the new plastic body.  It became unstable, and only worked sporadically.  Needless to say this isn't suitable for a gift, and I'll need to fix it before Amberly can use it.

Fortunately, I had already planned to create a custom PCB design for the next phase of the project.  PCB, for those of you who may not know, means "Printed Circuit Board".  PCB's aren't susceptible to any of the instability issues that are inherent in wire-wrapped boards, which are prone to lose wires, shaky connections, etc.  This is what bit me at Christmas.  The wire-wrapped prototype circuit proved too fragile to be transferred from one body to the next, and something broke.  The design is solid, so it makes sense to take the plunge and transfer everything to a PCB.

Wire wrapping is a great technique for quickly prototyping a concept circuit, but it is never to be considered a good long-term solution for circuit design.  The downside, of course, is the additional time and money required to produce a good PCB design. Fortunately the fundraising efforts on the IndieGoGo campaign, along with a few other donations, has allowed the project to move forward.  A PCB is being designed now, and should be available for testing soon. 

The initial PCB will replicate the same features of the existing Frankenkindle device.  Since the primary goal is still to give it to Amberly as a (very belated) Christmas gift, I want to get it functional as quickly as possible.  Once she's taken care of, I'll begin adding features and pushing the design to the next phase.

So what's next?  All sorts of good stuff.  New capabilities for the Frankenkindle itself, interfaces to new devices, and a few completely new ideas! 

Keep checking in, there's a lot more to come!