Deadbug Business Card

The thinnest functional business card in this contest.
"Just make a QR code out of LEDs it'll only take a couple of hours."

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This is a dead-bug LED business card slash flashlight. Coming in at under 1mm (0.96mm according to my caliper) this is probably the thinnest working project in this contest. Maybe tomorrow if I'm feeling lucky I'll sand it thinner. There is room for growth (READ: SHRINKAGE) there. Designed for upgradeability. The flashlight is thousands of lumens, depending on your power supply and risk tolerance.

The schematic is source-available but not for commercial use. I don't want you corporate pirates stealing my R&D. It's now 6AM in a different time-zone so I gotta type this up and submit it. I gotta be up at 8AM so I guess I'll get an hour or so of sleep tonight if I skip the shower. Be sure to check the instructions they are extremely detailed so you can make your own hyper-thin flashlight that goes to my website too.

Also the whole thing, including usb port, fits inside a business card. That's all extra space between the QR and the port.

This was supposed to take a couple hours and ended up taking a couple of days. See the build instructions if you, too, want to see how you can make an "easy" project hard. Skipped sleep and submitted with less than an hour to the deadline.


Proof that it works.

MPEG-4 Video - 36.50 MB - 07/02/2024 at 18:50



Source Available. Non-commercial use only.

Portable Network Graphics (PNG) - 22.78 kB - 07/02/2024 at 12:10


  • 1 × Jolly Jeff's Shenzen Express membership
  • 250 × The first LEDs you can have delivered
  • 1 × USB socket
  • 1 × Wife's hairdryer
  • 1 × A psychotherapist For when you question why you ever started this and if you really want to finish it.

View all 7 components

  • 1
    Realize you're late and order parts.

    Order all the SMD LEDs you can find for next-day delivery on Jolly Jeff's Shenzhen Express. Not enough? Find another seller. Who cares if they don't match? Also get the first set of usb sockets that'll arrive. Get some 18awg wire (it's under 1mm) and some 24awg wire (This can sit on the pads and still be under 1mm). Also get some high-temp double-sided tape. It's not hot enough to survive much direct iron contact but YOLO so just send it and see what happens.

  • 2
    Lose a few LEDs and realize that you have to get creative with your URL because now you don't have enough for all those characters..

    This step is mandatory.

  • 3
    Figure out QR code

    You need a low-level QR library like so you can modify the code until it works. Turn error correction all the way down, and then keep changing your URL until it the qr is the minimum size possible. Change the mask pattern until there's no large blocks of light or dark pixels.
    Now's the fun part: Count the pixels and make sure you have enough LEDs. There should be less than 250, with some allowance for losing them or burning them out.
    Print out a dozen copes of  your QR code until it is sized like a business card and each pixel is roughly the size of a 1206 led.

View all 26 instructions

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