SMD LEDs_f.lashes, how to go about it

Hello all

I saw this project a while ago called f.lashes - basically its a mini strip of LEDs that are glued (using fake eyelash adhesive) to just above your eyes. A small circuit board is secured to the back of your head with hair pins and thin skin coloured/copper wires connect board and LEDS. The board has a couple of buttons to implement different modes, one of which matches movement with flashing.

It's a simple fun project, and one which was launched and did well on Kickstarter but they aren't available to buy anymore.

I'm going to a festival in a couple of weeks and would really like to make my own. Any suggestions on where to start.

  • Should I use an Arduino lillypad? They are often used for wearables, or a Nano, or not use an Arduino at all.
  • What kind of LEDs? SMDs? Would I have to run two wires to each LED in the strip (I think the example uses 12 LEDs
  • Any advice on beat matching or vibration matching so the LEDs flash according to the users movement, or the music you are listening to

Any help would be greatly appreciated

henri_lacoste:
Should I use an Arduino lillypad? They are often used for wearables, or a Nano, or not use an Arduino at all.

I don't have experience with wearables, but I think the main reasons to use the LilyPad is because it's easy to connect conductive thread and perhaps because the round shape is less likely to poke you when sewn into your clothing. If you aren't using conductive thread or worried about corners on the board then the Pro mini might be a better choice, since it's significantly smaller than the LilyPad, and cheaper too! The 3.3 V version of the Pro Mini is just as friendly to being powered by batteries as the LilyPad.

henri_lacoste:
What kind of LEDs? SMDs? Would I have to run two wires to each LED in the strip (I think the example uses 12 LEDs

SMD LEDs are available in much smaller sizes than the non-SMD ones and won't have pointy bits sticking out the back of the circuit board. If you used addressable LEDs then you could just have 3 or 4 wires (depending on which type of addressable LED) total for each strip and be able to individually control the LEDs. The common addressable LEDs are usually in a 5mm x 5mm package, which might be a bit big for your application. However, the WS2812B-2020 is a 2mm x 2mm package, which would be super nice for your application.

If you are happy without individual LED control and can go with a single LED color, then you can control regular non-addressable LEDs with only 2 wires. That strip of LEDs wired this way will likely draw more current than your Arduino's IO pin can safely supply (35 mA) so you'd need a MOSFET to control the LEDs.

If you do need individual control of non-addressable LEDs, at most you'll need one wire per LED + one wire for current return for the entire strip. You can do it with less wires if you multiplex the LEDs. Look up "charlieplexing".