This Electronic Business Card Visualizes Audio; Demonstrates Skillz

The fate of every business card is a short trip to a long life in the landfill. But that’s because business cards are cheap paper and the only reason anyone accepts them in the first place is out of obligation. The only way to alter that paradigm is to create a business card that is cool. Alex pulled that off by building an electronic business that visualizes audio and simultaneously demonstrates his skillz.

A good business card needs to grab attention. It also needs some obvious value (either inherent or implied), so the recipient keeps it. Alex achieved both with this PCB business card.

Its core function is visualizing audio frequency band levels, just like that sweet hi-fi stereo receiver your dad owned when you were a kid. It listens through an onboard microphone, then displays the visualization across an 8×5 grid of RGB LEDs in real-time. The PCB also has Alex’s contact information — including QR codes pointing to his LinkedIn profile and online portfolio — printed on silkscreen, so interested parties can easily find him.

But Alex also took an overkill approach, because the card has an ESP32-S3 doing the audio processing. That hosts a web interface that users can access to change the visualization mode between a scrolling RMS voltage waveform and a standard eight-band spectrum analyzer. They can also tweak other settings, like the LED colors.

Tinkerers can completely reprogram the ESP32 to alter the behavior, which makes this business card perfect for handing out at hardware conferences. There are no guarantees in life, but I think it is safe to say that people will be very reluctant to toss Alex’s business cards in the trash and that puts him way ahead of the competition.