The FTC Robotics competition mostly uses two Android phones per robot: one for the robot and one for the controller. They use WiFi Direct to link up.
For a while (and in some cases still) the phones only supported 2.4GHz.
Congestion on the 2.4GHz bands may or may not lead to disconnects during competition play, so a general rule is no 2.4GHz networks. No hotspots, no access points, nothing.
Now in my use case I needed to deploy some cheap wireless devices to do things like queuing, automation, camera tally lights, etc. but couldn't because of that restriction, since many devices (Raspberry Pi, ESP32) only supported 2.4GHz. I ended up using the RTL8720DN or devices that contain it such as the Seeed Wio Terminal.
OTG is used for the USB game controller(s) to the Android phone on the "driver" side. On the field, there's a second Android phone attached to the robot which receives the input from the driver side Android phone.
Now in my use case I needed to deploy some cheap wireless devices to do things like queuing, automation, camera tally lights, etc. but couldn't because of that restriction, since many devices (Raspberry Pi, ESP32) only supported 2.4GHz. I ended up using the RTL8720DN or devices that contain it such as the Seeed Wio Terminal.