6 ms·

I would if I could program them relatively easily. And if there were other colors then just red LEDs.

crote 3y ago
Multi-color is probably not really possible at a reasonable price point because you'd need twice as many vias and traces in the same space for RGB compared to just R. You _can_ get it manufactured, just not in low quantities at a price anyone would be willing to pay. There are 1.1x1.1mm addressable LEDs available[0] which should be quite doable, but those require quite a high voltage and have an unacceptably high idle power consumption: a 52-LED matrix would draw 15mA with all the LEDs off! As to single-color non-red: the main advantage of red LEDs is that they can operate on a very low voltage. The exact same board with blue LEDs would have a significantly shorter battery life - if it's even possible at all. These earrings are probably using two SR521 batteries, which start at about 1.55V and discharge to about 1V[1] - so the earring is operating on 3.1V to 2V. You can get red LEDs which work with as little as 1.7V, but blue LEDs need about 3V to operate _at all_. You'd either have about 1/3rd of the battery life, or you'd have to add a third battery. [0]: https://www.adafruit.com/product/5849 https://www.adafruit.com/product/5849 [1]: https://img5083.weyesimg.com/uploads/xtk5s4z6.allweyes.com/images/15446843737777.jpg https://img5083.weyesimg.com/uploads/xtk5s4z6.allweyes.com/i...
- dekhn 3y ago
  Boost circuits are common for driving LEDs, for example a joule thief would be perfect for running this on fewer batteries.
  - kragen 3y ago
    true, but it's challenging to get a boost converter, even a very simple one like a joule thief, into the space of this earring; i think it's too small for a millihenry. using a larger number of smaller batteries might be a better option
  - crote 3y ago
    True, but that's still going to consume more energy - not to mention the boost circuit probably taking up more space than the additional battery.
    - dekhn 3y ago
      It looks like you can get reasonable SMD boost chips and pack them and their entire support infra in <10mm https://hhtronik.com/product/uboost/ https://hhtronik.com/product/uboost/ which is about the same as two batteries as used in this project.
- planede 3y ago
  As for multi-color individual green and blue leds could be just mixed in. Do blue leds consume significantly more power too for the same brightness, or only their voltage is higher?
  - crote 3y ago
    Great question! Each individual photon carries more energy, so I'd assume they do indeed consume more overall power. But maybe eye sensitivity compensates for that?

Multi-color is probably not really possible at a reasonable price point because you'd need twice as many vias and traces in the same space for RGB compared to just R. You _can_ get it manufactured, just not in low quantities at a price anyone would be willing to pay. There are 1.1x1.1mm addressable LEDs available[0] which should be quite doable, but those require quite a high voltage and have an unacceptably high idle power consumption: a 52-LED matrix would draw 15mA with all the LEDs off! As to single-color non-red: the main advantage of red LEDs is that they can operate on a very low voltage. The exact same board with blue LEDs would have a significantly shorter battery life - if it's even possible at all. These earrings are probably using two SR521 batteries, which start at about 1.55V and discharge to about 1V[1] - so the earring is operating on 3.1V to 2V. You can get red LEDs which work with as little as 1.7V, but blue LEDs need about 3V to operate _at all_. You'd either have about 1/3rd of the battery life, or you'd have to add a third battery. [0]: https://www.adafruit.com/product/5849 https://www.adafruit.com/product/5849 [1]: https://img5083.weyesimg.com/uploads/xtk5s4z6.allweyes.com/images/15446843737777.jpg https://img5083.weyesimg.com/uploads/xtk5s4z6.allweyes.com/i...

dekhn 3y ago
Boost circuits are common for driving LEDs, for example a joule thief would be perfect for running this on fewer batteries.
- kragen 3y ago
  true, but it's challenging to get a boost converter, even a very simple one like a joule thief, into the space of this earring; i think it's too small for a millihenry. using a larger number of smaller batteries might be a better option
- crote 3y ago
  True, but that's still going to consume more energy - not to mention the boost circuit probably taking up more space than the additional battery.
  - dekhn 3y ago
    It looks like you can get reasonable SMD boost chips and pack them and their entire support infra in <10mm https://hhtronik.com/product/uboost/ https://hhtronik.com/product/uboost/ which is about the same as two batteries as used in this project.
planede 3y ago
As for multi-color individual green and blue leds could be just mixed in. Do blue leds consume significantly more power too for the same brightness, or only their voltage is higher?
- crote 3y ago
  Great question! Each individual photon carries more energy, so I'd assume they do indeed consume more overall power. But maybe eye sensitivity compensates for that?