If you have used the ATEM production switchers long enough you probably noticed that it’s missing a wireless tally light option. That’s no longer the case.
KvitkoIT has engineered and released a wireless tally light system for ATEM switchers which can be ordered or done as a DIY. The kit comes with a transmitter (which connects to the same network as the switcher using a Cat5 cable) and multiple receivers (which attach to your cameras using a hot shoe mount). This is all wireless so no wires are required between the transmitter and receivers.
The kit is Arduino-based so it’s fully customizable.
Check out the ATEM Wireless Tally Light Kit at KvitkoIT.