Enginursday: Apogaea and the Propagand-Eye

Learn about the Propagand-Eye, a custom badge created for a soldering workshop at the Colorado Burning Man regional event, Apogaea.

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Apogaea (or Apo for short) is the official Burning Man Regional Event for Colorado, which operates under the guidelines of Burning Man’s 10 Principles. Five years ago, the SoundPuddle made its splashing debut as an art-grant funded project for Apogaea. Since then, our camp, known collectively as Electron Village, has been fortunate enough to create and share more and more electronic art, thanks to Apo's focus on and dedication to the arts.

In previous years we had also put on a soldering workshop at the event. In 2013 and 2014 we taught around 100 people each year how to solder. A unique PCB and kit was created for the participants.

This year we're bringing the soldering workshop back with a new badge for attendees to solder and enjoy. Meet the Propagand-Eye!

Propagand-Eye

The Propagand-Eye, named for the theme of Apogaea this year, propaganda, is an eyeball-shaped PCB onto which participants will solder addressable LEDs as well as a variety of other components to make their own blinky badge they can wear with pride. Once assembled, the badges will be able to communicate with one another via infrared (IR) communication, creating an interactive game in which participants will be able to collect different blinky modes from other badges. This will create many opportunities for interaction among participants long after the workshop is over.

What seemed like a simple task --- making a badge for a soldering workshop --- evolved into a full project with two people, one hardware and one software, putting in countless hours to create a truly interactive experience.

Check out the repository below. There you can also find information about the previous years' badges.

Hardware

I was fortunate enough to spend some time in the SparkX lab, which reinvigorated my desire to design PCBs. The experience was enough to motivate my art-grant submission. I had ordered prototypes before I was approved, knowing that even if I did not get the grant, they would make for a great experiment. For the protos, I pitted three fab houses against one another: OSHPark, BasicPCB, and JDBPCB by means of ALLPCB. You can see the results in the table below. Keep in mind that all three orders were placed on 4/11.

Total Order Cost # of PCBs Fab House Cost/PCB Date Arrived
$39.70 3 OSHPARK $13.23 4/21
$40.46 10 ALLPCB
$4.05 4/17
$86.75 5 BASICPCB
$17.35 4/17


ALLPCB has been my go-to thus far. They arrived just as fast as the BasicPCB, but they had more options for mask colors and board finishes than BasicPCB, which only offered traditional green.

alt text

Here's a shot of the final PCBs.

front

Front

back

Back

I got my stencil from OSHStencil, which I can't recommend enough. There were enough changes from the proto to the final to mandate a second order, but the stencil turnaround time was negligible to the PCB turnaround times.

The last major piece of hardware needed was a test fixture. One was ordered not too long ago. However, between it being combined with other orders and the most recent Chinese holidays, it got held up. With little to no time left to order one from even the fastest fab house, I set out to build my own using an OtherMill PCB mill and was able to piece together a functional pogo bed with no problem.

A Raspberry Pi was added, and *POOF* instant programming testing station.

test jog

The voltmeter is attached to check the single AA boost circuitry.

Software

Adding the IR communication was in no way new or novel; the idea came from the DefCon 23 Hardware Hacking Village Badge. And, unbeknownst to me, the Propagand-Eye was being developed around the same time as the SparkFun Roshamglo Badge , which uses IR communication to play Rock, Paper, Scissors between two users. In the case of the Propagand-Eye, the IR communication is used to participate in a "gene" collection game.

Using the 10 addressable LEDs in the center of the eye, 16 unique animations and 16 unique color sets were coded to create 256 unique gene combinations. Each board has that gene stored in EEPROM, so it always remembers its base gene. That is the only animation and color set available to the participant when his or her badge is completed and first powered. But once the badge "sees" another badge, they flash white to indicate that they would like to initiate an exchange of genes. All the users have to do is press the button after a white flash. That gene is then stored in EEPROM, and if/when the badges see each other again, they flash red indicating they have already exchanged genes.

A Python script was written to allow for batch programming of the EEPROM to give each eye a unique gene out of the bag. It uses a list of genes generated by another script.

Engineers Hate Surprises

One big hiccup occurred with the ATMEGA328p's used. That chip was chosen to allow the board to be Arduino compatible and allow for both experienced and inexperienced users to hack their badges after the event.

The lesson, shared here first, is never mix different batches of any part if you can avoid it. Several ATMEGA328p's were scavenged to save money, and about 2/3 were bought new. When it came time to batch program, the new ones would not accept the bootloader, which resulted in a large game of find the source of the problem. The issue was overcome, but not with a solution that provided any answer as to why the ICs did not behave as the ones found so regularly elsewhere. Rather, it was a chaotic menagerie of different programmers, swapping parts and using all three major operating systems. The working theory is a bad batch of internal oscillators was plaguing the newer ICs. But what matters is that they all got programmed and are sitting here, kitted, awaiting a plethora of participants to build them, play with them, and hopefully learn from them at Apogaea.

Who knows what'll happen if you get a bunch of them together...


If you want to build your own Propagand-Eye, you're in luck as the last-chance ticket sale for Apoagea just so happens to be today, June 1, at 7 p.m. MST.


Comments 9 comments

  • It's not affordable with US based PCB house when i need larger PCB, is there any Chinese pcb service like Seeedstudio PCB recommend?

  • If you don't mind me asking, what was the ball park BOM costs? I'm not by any means an engineer, but a friend of mine and I were contemplating a similar festival badge. I did some research into what it might cost per unit and wrote the idea off.

    • The BOM was roughly $10/kit. Not the cheapest. However, I feel that could be decreased if SMD LEDs were used. But that requires more pre-building before the event. The art grant received from Apo helped tremendously. The rest was paid for by myself and a few generous camp mates who pitched in.

  • Sounds like a neat project, as well as a fun event. Too bad I won't be able to make it. (A question for future reference is "handicapped accessibility" -- I went to the "Dayton Hamvention" for the first time this year (actually in Xenia, OH), and had wasn't able to get to most of the "flea market" area. (I'm still cleaning mud off my scooter.)

    Anyway, it sounds like you're ordering lots of boards. Although it's (probably) too late for this year, I'd suggest that you look at Gold Phoenix to do your PCBs. They're quite economical, and reasonably fast, provided you need a total of at least 155 square inches of PCBs. (They were the "go-to" source for the company I was working for about 4 years ago. When I needed a few PCBs of about 2 sq. in. each, I ended up with a drawer full of "spares".)

    Also, I'm sort of wondering if maybe the programming issues might indicate counterfeit parts? There was a rash of that with FTDIs, in the not too distant past...

    • i have used wellpcb,also a PCB Manufacturer from China and they gave me a well impression of Chinese PCB Manufacturing. It was amazing that i need rush boards although with only 10PCs but they regards very important and i received my boards in only 4 days since i ordered. And then i went to soldering.Their boards is not expensive but also with the super quality! I was very satisfied.Maybe i will try other options but i will also keep the cooperation with WellPCB.

      • Thanks for the tip about WellPCB -- I've taken note of them and will take a closer look next time I do a PCB. One thing I notice is that the website is the Australian "subsidiary" of a Chinese company. Since I'm in the U.S., I wonder about that extra "international" layer. (I've done a couple of Kickstarter things from Aussie companies -- one of which SparkFun did the "distribution" for. Those tend to take time, so extra delays aren't as noticable.) As a "heads up" for anyone else reading this, be SURE you know the bank's policies for your credit card BEFORE you order anything from a foreign company -- I got a rather rude surprise when I ordered something from a Canadian company some years ago -- an extra charge of over 10% from the bank.

        And I want to include a BIG thanks to SparkFun for sending me an e-mail alerting me to a new reply to a post from nearly two months ago! I would have missed it without that e-mail!

    • Thanks for the reply. The environment in which Apo is held is not the most forgiving for handicap accessibility, but there are roads for bikes and carts.

      We use Gold Phoenix for all our PCBs here at SparkFun. They are a great business to work with. I just wanted to try some other options to compare.

      I'm leaning less towards counterfeit parts since we eventually got them working, but it's certainly a possibility.

    • Hamvention is amazing! Haven't been there in years, but last time I went, it took ALL DAY just to walk the outside flea market. Even then, you couldn't actually see everything in just one day. I remember years where it was 95 degrees and not a cloud in the sky and years with large hail and flooding. It's a shame Hara Arena closed. That place had 'character.'

      What they say is true. "If you can't find it at Hamvention, it doesn't exist."

      • What I'd heard was that Hamvention is a 3 day event that only takes 5 days to see everything. It took us well over one day just to get to the stuff we could see with the scooter. I'm guessing that in the two days we were there we only saw about 5% of the outdoor flea market, and spent several hours in the various presentations. (One of them was about the things we should do to get more young people interested in "doing" electronics -- I'd estimate that there were about 60 people in the room, with maybe 3 or 4 in the "40-55 year old" bracket and the rest in the "56 and over" [including myself]).

        In general, I thought they did a fantastic job of putting it together when they'd had to change venues on just 9 month's notice (from one that they'd been using for over 50 years). There were a few "learning experiences" (like getting the cars into the parking lots), but those were a lot better the second day. The only thing I can really criticize them on was the use of "cutesy" building names, and NOT including any indication of the "actual" names in the program -- this was especially disconcerting (and confusing) when you happened to be at the "back" or "side" of a building, as the banners with the "cutesy" names were only on the "front" of the buildings.

        I'm really glad we went -- it was my first time (as well as my girl friend's first time). We had a two day drive to get there from New England (I was in NE for other reasons, rather than in AZ). I don't think I'd drive as far for it again, though I might go if I happened to be in the Ohio area for other things. (I could then maybe put the extra money for two nights on the road towards renting a scooter with larger wheels -- I talked to someone who had rented one, and he said they were getting $75/day for them.)

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