Happymodel CrazyF411 is a board with regulators, FC and receiver in one. The board is based on an ICM42688P gyro supporting a refresh rate of up to 8KHz and an F411 processor. The board supports power supply of 2-4S Lipo batteries and a current of up to 20A. It is especially suitable for building light 2-3" copters. The board also includes an integrated current sensor.
A big advantage of the board is the integrated ELRS receiver, which is connected via UART. Classic integrated receivers are connected via the SPI bus and their firmware is part of Betaflight. The UART receiver is a full-fledged classic Happymodel EP1 receiver that can be independently updated or set up via Wifi. The ELRS receiver is connected to UART2. By connecting the 5V and E5 pins, the ELRS receiver can be disabled and the UART can be used to connect another device. The antenna is connected to the ELRS receiver via an IPEX connector.