Congrats to Adam Gutterman for finding the cake. The cake is hidden on an internal ground layer, printed in “negative” (i.e., lack of copper on a copper plane). The visible-light photos I make of the motherboards are all taken with front-lit scanners, so the negative image is virtually invisible when viewed in that way. There’s also a solid copper ground plane behind the cake as well, so you can’t simply hold the board up to a light to find the cake (hence the larger bounty). The only two methods to find the cake are to either X-ray the board, or to mechanically delaminate the board using either knife or sandpaper (or both) to reveal the cake. And for the record, the region where the cake is located is electrically inert, such that defacing the chumby logo to reveal the cake does not damage the function of the device.

Adam tells the story of how he found the cake:

I’m an EE at a company that outsources almost all of our board assembly tasks. Anything more complicated than QFPs gets sent out–it’s not worth engineer time to assemble things, especially since we’re not particularly skilled assemblers.

Unfortunately, not all projects have the budget for professional installation. During a recent personal project, we hand-assembled a small batch of boards that had pretty tiny LGA packages. Our initial yields were pathetically low, and we suspected that there were some shorts to blame. Since we didn’t have a professional lab to use, we had to go with our personal connections. The board designer found a friend that had access to a medical x-ray machine, so we sweet-talked ourselves into a quick run through their machine. The resulting film let us get over our hump and bring our boards up successfully.

Anyway, as soon as I saw your post, I decided to do the same thing. Unfortunately, the x-ray office was closed for the long weekend, so I wasn’t able to get my ‘stat’ order in until Monday. When I got the films last night, the focus wasn’t clear enough for me to be able to make out any important features. The films, incidentally, are shown in the directory that I posted on your blog. Undeterred, I spent last night trying to get permission to use a PCB inspection facility at a local university. The okay came through this morning, so during lunch today a couple of us set the board up and started looking for features. It took only a couple of minutes to find the cake once we had access to the right equipment!

I didn’t think it would be found so quickly…just one week from original post, for an item that’s entirely concealed on an inner layer. Then again, ladyada got her open-source Kinect drivers in about the same period of time.

This is probably an interesting datapoint for folks who support the theory that burying traces on the inside of a PCB are an effective method for obscuring the transmission of secret information between chips.

So, first the pitch — for your Black Friday shopping pleasure, here’s a couple of things that will help scratch that itch to play around with hardware.

First of all, two chumby-powered devices under the Insignia brand in Best Buy are on sale for Black Friday. The original 8″ Infocast device — an 800 MHz linux PC with an 8″ SVGA LCD and touchscreen — is rumored to be on sale for as low as $99 in some stores, although Best Buy’s on-line price pegs it at $129. Either way, it’s a smashing deal for a linux PC.

The other chumby-powered device is the 3.5″ Infocast, which you can think of as the Chumby One Internet Radio’s battery-less little brother. This, too, is on sale for Black Friday, and at just $79, it’s a steal.

The motherboard for the 3.5″ Infocast is shown below, and if it looks familiar, you’d be right.

One small improvement to the 3.5″ Infocast board is the addition of a “mod port” which breaks out several GPIOs, I2C, composite video, and a spare USB port to a 0.1″ pitch header (which is a subset of the pinout that’s featured in the chumby hacker board), shown below.

sudo find me a Cake!
So here’s where the Cake comes in. Somewhere on the motherboard of the Infocast 3.5″, I’ve hidden a cake — the cake is not a lie. The first person who can find the cake and post a photo of it within the next two months will be given a cash prize of US$300. Put in perspective, that’s two months’ wage for a Chinese factory worker (and that’s after the across-the-industry 20% raises that were effected by a string of suicides at Foxconn, where the iPhone is assembled). Given that the standard monthly prize for Name that Ware is just $10, this gives an idea of how hard I think it is to find the cake. But, I promise you — the cake is not a lie.

Bitbake it yourself!
And here’s where the Bitbake comes in. For those who have been wanting to build your own firmware for both the 8″ and 3.5″ chumby platforms, a simple solution finally exists. As announced on the chumby forum, there is now an easy to use Open Embedded configuration that will allow you to build and customize, from scratch, your very own firmware image.

You can configure the firmware to be anything from a minimal console-only build, to one that includes a window system and web browser of your choosing. The build configuration is “complete” in the sense that the product of the OpenEmbedded build is a binary image that you can directly write to the microSD card and boot with no need for further massaging.

Have a happy holiday weekend!

Eric Gregori from EMG Robotics recently linked me to a YouTube video originally posted on imxcommunity.org of a chumby One that he turned into a bipedal walker. This has got to be the most omgwtfbbq-cool robotics demo I’ve seen of the chumby One to date. Check it out:

One small step toward our future robotic overlords…but hey, at least they’ll be open source. That might even be an improvement over what we have today.

A couple months back, Name that Ware featured the Insignia Infocast by Best Buy Exclusive Brands. While it’s marketed as a device for viewing chumby apps and sharing photos, as far as the DIY crowd is concerned, the Infocast is a $169, 800 MHz linux machine with an SVGA touchsreen, 128 MB of DDR2, and a 2GB disk drive.

An example of the versatility of the platform is hb‘s recent port of the Qt UI framework running webkit to the Infocast, pictured running above. For those who want to build it themselves, there are instructions on the chumby wiki and a forum for questions; or you can just download a pre-packaged binary image that you can uncompress to a USB thumb drive, toss it into one of the ports on the back, reboot and use. Note that the implementation assumes a USB keyboard plugged for text input.

Of course, this is just scratching the surface on what you can do with the platform. There are folks working on porting Android and OpenEmbedded, and the hardware reference schematics are available for those inclined to the soldering iron.