n-teller-xl-diy is an IoT device that displays the number of checked in participants and visitors at the hackerspace called Revelation Space (or RevSpace).
n-teller-xl-diy
I scaled the n-teller up. Where the desk version used a 0.36-inch module, this one builds four 2.3 inch 7-segment digits out of SK6812s and 3D prints, so the RevSpace headcount is readable across the room.
Parts and prints
- An ESP8266 on a custom PCB.
- Four 3D-printed 2.3 inch 7-segment digits filled with SK6812 LEDs.
- A level shifter for the LED data.
- A printed stand.
Reading the feed
The ESP8266 subscribes to `revspace/doorduino/checked-in` and `revspace/state` on the RevSpace MQTT server. Each message updates the display manager, which paints the count across the digits and colors it by the space state. I fitted a level shifter because 3.3V sits below the SK6812's VIH; one batch of LEDs glitched without it.