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Revision as of 13:20, 15 July 2013 by Bunnie (talk | contribs) (Phage Locator)
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These are projects for phage / BM2013. If you ended up here and you're not part of phage, then fnord.

Phagelings: please record interest at this gdoc

Phage Band

The phage band is a small flexible circuit board that's designed to be soldered in a loop of WS2812 RGB LEDs. It is about the size of your thumb.

It's meant to be a convenient and compact way to make a ribbon of LEDs do something interesting.

As of early July, the board has been sent out for fabrication and should be ready well in advance of BM2013.

The board has the following features:

  • Powered off of +5V via microUSB header (for use with battery packs commonly used to charge cell phones)
  • ATTiny85 for pre-programmed light patterns
  • A single pushbutton to control operation mode
  • If both ends of the WS2812 ribbon is soldered to the board, the ATTiny85 can automatically detect the length of the LED string
  • Microphone and pre-amp with gain control selection (aka "robot heart mode")
  • Flex circuit construction
    • programming header and microphone section can be sheared off with scissors if they are not needed for a more compact driver circuit
    • Steel stiffener plate under ribbon solder point and microUSB header for mechanical robustness

Below are renderings of how the board will look:

phageband3.png phageband2.png phageband1.png

Below is what the board looks like after you've sheared off the microphone and programming headers:


Below is a concept of how the board might look mounted into a ribbon of WS2812 LEDs:


Phage Locator

The phage locator is a design proposal. If enough phagelings are interested, I'll complete the design and get them built.

The idea of the phage locator is it's a little "badge" you can wear around. It has LEDs (of course), and it has a "locate" feature. When the button at the base of the board is pressed, an RF beacon is sent out. Any companions in the vicinity (targeting 20-30m range) will pick up the beacon and start strobing.

When not in locate mode, the board cycles the lights, and has a microphone so it can react to sound; although the exact behavior in reaction to sound is still a work in progress (I've got an ATTiny to work with here, not really a DSP giant :P)

Below are renderings of what the board might look like.




you can download schematics and layout in PDF format here: http:/

Here is the feature summary:

  • Powered off of +5V via micro-USB (compatible with most cell phone battery packs)
  • 6 RGB LEDs around the capsid that can cycle indepedently
  • 16 white LEDs around the legs that cycle in a "gang"
  • RF beacon, activated by pushbutton
  • RF receiver - causes strobing action when beacon is detected
  • Microphone to cause lights to cycle in the presence of sound
  • ~4" tall
  • Made out of 1.6mm FR-4 PCB
  • Matte black soldermask with white silkscreen, gold trim

With a sufficiently modest light cycling pattern, it should last a day on a typical cell phone charging battery pack. Quiescent draw of radio in passive receive + other bits is estimated to be 20mA @ 5V. A conservative light cycling pattern (20% duty on, 50% brightness) will burn about 50mA @ 5V time-average. So about 70mA-100mA estimated current draw, or 350-500mW. A small "lipstick" style cell phone charger pack will have about 9Wh capacity. That's ~18-25 hours run time. Of course, the primary source of current draw is the light pattern. A full-on pattern will draw about 200mA @ 5V, or 1Wh; just idling with lights off waiting for a signal, it draws 0.1Wh. So that's a 10:1 change in runtime based upon the light pattern you choose.

See spreadsheet for update on cost.