On Air light

Waits for a client to connect via wifi and lights up RGB led strip according to received messages. Designed to be run with obs-onair to show whether or not it's safe to open the studio door.

Hardware

The example device is built from a cheap esp32 board, a piece of a ws2812 rgb led strip and an extra micro-usb port to get a better position for power input.

The 5 volts and ground of the extra usb port are connected to the VIN and GND pins closest to the usb port on the board. The led strip is connected to the same two pins plus D13, which is the data pin right next to the previous two.

What the light patterns mean

Rainbow leds: Connecting to wifi
Off: No client connected
Yellow: Client connected, OBS not live
Red spin: Client connected, OBS live
Red blink: Some sort of error

Used network protocol

Built on top of TCP
All messages 128 or fewer bytes of length
Any message starting with byte 0 means "off air"
Any message starting with byte 1 means "on air"
All other messages are invalid

To configure and use

First requirement is esp idf development environment. Follow https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/#installation-step-by-step

run idf.py menuconfig and set the wifi SSID and password and LED information

run idf.py monitor to see what IP the device gets.

Use nc [ip] [port] to test that the setup works. The light should turn yellow when connected and turn off when disconnected.

run idf.py build to build the binary.

run idf.py flash -p [port] to flash the program on the esp32.

Development

I feel like this is a good base for all sorts of wifi connected led status lights. The code is probably not good for live control. The logic behind the code is as follows:

common.h defines state_ enum.
main.c
creates a global state and sets its initial value
Yes, it's not the most beautiful solution, but it works for this simple application
starts tasks for led control, wifi connection and tcp server
led task checks the global state and updates leds accordingly on a timer
wifi connection task tries to connect to the configured wifi network on a loop
tcp server task waits until wifi is connected and starts a server that accepts one connection and handles messages received from that client, setting the state accordingly.