n-teller is an IoT device that displays the number of checked in participants and visitors at the hackerspace called Revelation Space (or RevSpace).
It connects to the RevSpace MQTT server via WiFi using an ESP8266.
The MQTT server publishes to a few topics of interest that are subscribed:
- revspace/doorduino/checked-in: this is the current total checked people.
- revspace/state: the current state (open or closed) of the hackerspace.
hardware/n-teller-schematic.pdf
See interactive BOM: hardware/bom/
You will also need:
- The pcb. See hardware/gerber/ for gerber files.
- 2x M3x12 BHCS screws.
- Optional 1x USB Type-C Female Chassis Connector.
In the 3d directory you can find a stand for the pcb.
Print n-teller-stand-w-usb-c-socket.stl. This will fit the optional USB Type-C Female Chassis Connector mentioned in the BOM. Or print n-teller-stand.stl and roll your own connection to 5V power supply.
Compile and flash the firmware located in the firmware directory. You will need PlatformIO for this. I recommend installing the PlatformIO extension for VSCode.
Double press the reset button (somewhat slowly). The letters AP will appear on the display. Now connect to a WiFi network with a name like nteller-bcddc2895fd2. Then go to: http://192.168.4.1/ and configure your WiFi.
PCB was designed to fit this type (pinout and dimensions) of 0.36" 4-digit 7-segment common cathode LED display:
| Model | Color | Tested |
|---|---|---|
| LFD036AAG-101 | green | |
| 3461AB | blue | ✔️ |
| 3461AG | green | |
| 3461AGG | jade green | |
| 3461AO | orange | |
| 3461AS | red | |
| 3461AW | white | |
| 3461AY | yellow |
